Introduction to FreeS/WAN



Table of Contents



Introduction Upgrading to FreeS/WAN 2.x Quickstart Guide to Opportunistic Encryption How to Configure Linux FreeS/WAN with Policy Groups FreeS/WAN FAQ FreeS/WAN manual pages FreeS/WAN and firewalls Linux FreeS/WAN Troubleshooting Guide Linux FreeS/WAN Compatibility Guide Interoperating with FreeS/WAN Performance of FreeS/WAN Testing FreeS/WAN Kernel configuration for FreeS/WAN Other configuration possibilities Installing FreeS/WAN How to configure FreeS/WAN Linux FreeS/WAN background FreeS/WAN script examples How to configure to use "make check" How to write a "make check" test Current pitfalls

User-Mode-Linux Testing guide Debugging the kernel with GDB User-Mode-Linux mysteries

Getting more info from uml_netjig

History and politics of cryptography The IPsec protocols Mailing lists and newsgroups Web links Glossary for the Linux FreeS/WAN project Bibliography for the Linux FreeS/WAN project

IPsec RFCs and related documents Distribution Roadmap: What's Where in Linux FreeS/WAN User-Mode-Linux Testing guide Debugging the kernel with GDB User-Mode-Linux mysteries

Getting more info from uml_netjig

How to configure to use "make check" How to write a "make check" test Current pitfalls

Nightly regression testing

How to setup the nightly build

Introduction

This section gives an overview of:

This section is intended to cover only the essentials, things you should know before trying to use FreeS/WAN.

For more detailed background information, see the history and politics and IPsec protocols sections.

IPsec, Security for the Internet Protocol

FreeS/WAN is a Linux implementation of the IPsec (IP security) protocols. IPsec provides encryption and authentication services at the IP (Internet Protocol) level of the network protocol stack.

Working at this level, IPsec can protect any traffic carried over IP, unlike other encryption which generally protects only a particular higher-level protocol -- PGP for mail, SSH for remote login, SSL for web work, and so on. This approach has both considerable advantages and some limitations. For discussion, see our IPsec section

IPsec can be used on any machine which does IP networking. Dedicated IPsec gateway machines can be installed wherever required to protect traffic. IPsec can also run on routers, on firewall machines, on various application servers, and on end-user desktop or laptop machines.

Three protocols are used

Our implementation has three main parts:

IPsec is optional for the current (version 4) Internet Protocol. FreeS/WAN adds IPsec to the Linux IPv4 network stack. Implementations of IP version 6 are required to include IPsec. Work toward integrating FreeS/WAN into the Linux IPv6 stack has started.

For more information on IPsec, see our IPsec protocols section, our collection of IPsec links or the RFCs which are the official definitions of these protocols.

Interoperating with other IPsec implementations

IPsec is designed to let different implementations work together. We provide:

The VPN Consortium fosters cooperation among implementers and interoperability among implementations. Their web site has much more information.

Advantages of IPsec

IPsec has a number of security advantages. Here are some independently written articles which discuss these:

SANS institute papers. See the section on Encryption &VPNs.
Cisco's white papers on "Networking Solutions".
Advantages of ISCS (Linux Integrated Secure Communications System; includes FreeS/WAN and other software).

Applications of IPsec

Because IPsec operates at the network layer, it is remarkably flexible and can be used to secure nearly any type of Internet traffic. Two applications, however, are extremely widespread:

There is enough opportunity in these applications that vendors are flocking to them. IPsec is being built into routers, into firewall products, and into major operating systems, primarily to support these applications. See our list of implementations for details.

We support both of those applications, and various less common IPsec applications as well, but we also add one of our own:

This is an extension we are adding to the protocols. FreeS/WAN is the first prototype implementation, though we hope other IPsec implementations will adopt the technique once we demonstrate it. See project goals below for why we think this is important.

A somewhat more detailed description of each of these applications is below. Our quickstart section will show you how to build each of them.

Using secure tunnels to create a VPN

A VPN, or Virtual Private N etwork lets two networks communicate securely when the only connection between them is over a third network which they do not trust.

The method is to put a security gateway machine between each of the communicating networks and the untrusted network. The gateway machines encrypt packets entering the untrusted net and decrypt packets leaving it, creating a secure tunnel through it.

If the cryptography is strong, the implementation is careful, and the administration of the gateways is competent, then one can reasonably trust the security of the tunnel. The two networks then behave like a single large private network, some of whose links are encrypted tunnels through untrusted nets.

Actual VPNs are often more complex. One organisation may have fifty branch offices, plus some suppliers and clients, with whom it needs to communicate securely. Another might have 5,000 stores, or 50,000 point-of-sale devices. The untrusted network need not be the Internet. All the same issues arise on a corporate or institutional network whenever two departments want to communicate privately with each other.

Administratively, the nice thing about many VPN setups is that large parts of them are static. You know the IP addresses of most of the machines involved. More important, you know they will not change on you. This simplifies some of the admin work. For cases where the addresses do change, see the next section.

Road Warriors

The prototypical "Road Warrior" is a traveller connecting to home base from a laptop machine. Administratively, most of the same problems arise for a telecommuter connecting from home to the office, especially if the telecommuter does not have a static IP address.

For purposes of this document:

These require somewhat different setup than VPN gateways with static addresses and with client systems behind them, but are basically not problematic.

There are some difficulties which appear for some road warrior connections:

In most situations, however, FreeS/WAN supports road warrior connections just fine.

Opportunistic encryption

One of the reasons we are working on FreeS/WAN is that it gives us the opportunity to add what we call opportuntistic encryption. This means that any two FreeS/WAN gateways will be able to encrypt their traffic, even if the two gateway administrators have had no prior contact and neither system has any preset information about the other.

Both systems pick up the authentication information they need from the DNS (domain name service), the service they already use to look up IP addresses. Of course the administrators must put that information in the DNS, and must set up their gateways with opportunistic encryption enabled. Once that is done, everything is automatic. The gateways look for opportunities to encrypt, and encrypt whatever they can. Whether they also accept unencrypted communication is a policy decision the administrator can make.

This technique can give two large payoffs:

Opportunistic encryption is not (yet?) a standard part of the IPsec protocols, but an extension we are proposing and demonstrating. For details of our design, see links below.

Only one current product we know of implements a form of opportunistic encryption. Secure sendmail will automatically encrypt server-to-server mail transfers whenever possible.

The need to authenticate gateways

A complication, which applies to any type of connection -- VPN, Road Warrior or opportunistic -- is that a secure connection cannot be created magically. There must be some mechanism which enables the gateways to reliably identify each other. Without this, they cannot sensibly trust each other and cannot create a genuinely secure link.

Any link they do create without some form of authentication will be vulnerable to a man-in-the-middle attack. If Alice and Bob are the people creating the connection, a villian who can re-route or intercept the packets can pose as Alice while talking to Bob and pose as Bob while talking to Alice. Alice and Bob then both talk to the man in the middle, thinking they are talking to each other, and the villain gets everything sent on the bogus "secure" connection.

There are two ways to build links securely, both of which exclude the man-in-the middle:

Automatic keying is much more secure, since if an enemy gets one key only messages between the previous re-keying and the next are exposed. It is therefore the usual mode of operation for most IPsec deployment, and the mode we use in our setup examples. FreeS/WAN does support manual keying for special circumstanes. See this section.

For automatic keying, the two systems must authenticate each other during the negotiations. There is a choice of methods for this:

Public key techniques are much preferable, for reasons discussed later, and will be used in all our setup examples. FreeS/WAN does also support auto-keying with shared secret authentication. See this section.

The FreeS/WAN project

For complete information on the project, see our web site, freeswan.org.

In summary, we are implementing the IPsec protocols for Linux and extending them to do opportunistic encryption.

Project goals

Our overall goal in FreeS/WAN is to make the Internet more secure and more private.

Our IPsec implementation supports VPNs and Road Warriors of course. Those are important applications. Many users will want FreeS/WAN to build corporate VPNs or to provide secure remote access.

However, our goals in building it go beyond that. We are trying to help build security into the fabric of the Internet so that anyone who choses to communicate securely can do so, as easily as they can do anything else on the net.

More detailed objectives are:

If we can get opportunistic encryption implemented and widely deployed, then it becomes impossible for even huge well-funded agencies to monitor the net.

See also our section on history and politics of cryptography, which includes our project leader's rationale for starting the project.

Project team

Two of the team are from the US and can therefore contribute no code:

The rest of the team are Canadians, working in Canada. ( Why Canada?)

The project is funded by civil libertarians who consider our goals worthwhile. Most of the team are paid for this work.

People outside this core team have made substantial contributions. See

Additional contributions are welcome. See the FAQ for details.

Products containing FreeS/WAN

Unfortunately the export laws of some countries restrict the distribution of strong cryptography. FreeS/WAN is therefore not in the standard Linux kernel and not in all CD or web distributions.

FreeS/WAN is, however, quite widely used. Products we know of that use it are listed below. We would appreciate hearing, via the mailing lists, of any we don't know of.

Full Linux distributions

FreeS/WAN is included in various general-purpose Linux distributions, mostly from countries (shown in brackets) with more sensible laws:

For distributions which do not include FreeS/WAN and are not Redhat (which we develop and test on), there is additional information in our compatibility section.

The server edition of Corel Linux (Canada) also had FreeS/WAN, but Corel have dropped that product line.

Linux kernel distributions

Office server distributions

FreeS/WAN is also included in several distributions aimed at the market for turnkey business servers:

Firewall distributions

Several distributions intended for firewall and router applications include FreeS/WAN:

There are also several sets of scripts available for managing a firewall which is also acting as a FreeS/WAN IPsec gateway. See this list.

Firewall and VPN products

Several vendors use FreeS/WAN as the IPsec component of a turnkey firewall or VPN product.

Software-only products:

Products that include the hardware:

Rebel.com, makers of the Netwinder Linux machines (ARM or Crusoe based), had a product that used FreeS/WAN. The company is in receivership so the future of the Netwinder is at best unclear. PKIX patches for FreeS/WAN developed at Rebel are listed in our web links document.

Information sources

This HowTo, in multiple formats

FreeS/WAN documentation up to version 1.5 was available only in HTML. Now we ship two formats:

and provide a Makefile to generate other formats if required:

The Makefile assumes the htmldoc tool is available. You can download it from Easy Software.

All formats should be available at the following websites:

The distribution tarball has only the two HTML formats.

Note: If you need the latest doc version, for example to see if anyone has managed to set up interoperation between FreeS/WAN and whatever, then you should download the current snapshot. What is on the web is documentation as of the last release. Snapshots have all changes I've checked in to date.

RTFM (please Read The Fine Manuals)

As with most things on any Unix-like system, most parts of Linux FreeS/WAN are documented in online manual pages. We provide a list of FreeS/WAN man pages, with links to HTML versions of them.

The man pages describing configuration files are:

Man pages for common commands include:

You can read these either in HTML using the links above or with the man(1) command.

In the event of disagreement between this HTML documentation and the man pages, the man pages are more likely correct since they are written by the implementers. Please report any such inconsistency on the mailing list.

Other documents in the distribution

Text files in the main distribution directory are README, INSTALL, CREDITS, CHANGES, BUGS and COPYING.

The Libdes encryption library we use has its own documentation. You can find it in the library directory..

Background material

Throughout this documentation, I write as if the reader had at least a general familiarity with Linux, with Internet Protocol networking, and with the basic ideas of system and network security. Of course that will certainly not be true for all readers, and quite likely not even for a majority.

However, I must limit amount of detail on these topics in the main text. For one thing, I don't understand all the details of those topics myself. Even if I did, trying to explain everything here would produce extremely long and almost completely unreadable documentation.

If one or more of those areas is unknown territory for you, there are plenty of other resources you could look at:

Linux
the Linux Documentation Project or a local Linux User Group and these links
IP networks
Rusty Russell's Networking Concepts HowTo and these links
Security
Schneier's book Secrets and Lies and these links

Also, I do make an effort to provide some background material in these documents. All the basic ideas behind IPsec and FreeS/WAN are explained here. Explanations that do not fit in the main text, or that not everyone will need, are often in the glossary , which is the largest single file in this document set. There is also a background file containing various explanations too long to fit in glossary definitions. All files are heavily sprinkled with links to each other and to the glossary. If some passage makes no sense to you, try the links.

For other reference material, see the bibliography and our collection of web links.

Of course, no doubt I get this (and other things) wrong sometimes. Feedback via the mailing lists is welcome.

Archives of the project mailing list

Until quite recently, there was only one FreeS/WAN mailing list, and archives of it were:

The two archives use completely different search engines. You might want to try both.

More recently we have expanded to five lists, each with its own archive.

More information on mailing lists.

User-written HowTo information

Various user-written HowTo documents are available. The ones covering FreeS/WAN-to-FreeS/WAN connections are:

User-wriiten HowTo material may be especially helpful if you need to interoperate with another IPsec implementation. We have neither the equipment nor the manpower to test such configurations. Users seem to be doing an admirable job of filling the gaps.

Check what version of FreeS/WAN user-written documents cover. The software is under active development and the current version may be significantly different from what an older document describes.

Papers on FreeS/WAN

Two design documents show team thinking on new developments:

Both documents are works in progress and are frequently revised. For the latest version, see the design mailing list. Comments should go to that list.

There is now an Internet Draft on Opportunistic Encryption by Michael Richardson, Hugh Redelmeier and Henry Spencer. This is a first step toward getting the protocol standardised so there can be multiple implementations of it. Discussion of it takes place on the IETF IPsec Working Group mailing list.

A number of papers giving further background on FreeS/WAN, or exploring its future or its applications, are also available:

Several of these provoked interesting discussions on the mailing lists, worth searching for in the archives.

There are also several papers in languages other than English, see our web links.

License and copyright information

All code and documentation written for this project is distributed under either the GNU General Public License (GPL) or the GNU Library General Public License. For details see the COPYING file in the distribution.

Not all code in the distribution is ours, however. See the CREDITS file for details. In particular, note that the Libdes library and the version of MD5 that we use each have their own license.

Distribution sites

FreeS/WAN is available from a number of sites.

Primary site

Our primary site, is at xs4all (Thanks, folks!) in Holland:

Mirrors

There are also mirror sites all over the world:

Thanks to those folks as well.

The "munitions" archive of Linux crypto software

There is also an archive of Linux crypto software called "munitions", with its own mirrors in a number of countries. It includes FreeS/WAN, though not always the latest version. Some of its sites are:

Any of those will have a list of other "munitions" mirrors. There is also a CD available.

Links to other sections

For more detailed background information, see:

To begin working with FreeS/WAN, go to our quickstart guide.


Upgrading to FreeS/WAN 2.x

New! Built in Opportunistic connections

Out of the box, FreeS/WAN 2.x will attempt to encrypt all your IP traffic. It will try to establish IPsec connections for:

FreeS/WAN 2.x uses hidden, automatically enabled ipsec.conf connections to do this.

This behaviour is part of our campaign to get Opportunistic Encryption (OE) widespread in the Linux world, so that any two Linux boxes can encrypt to one another without prearrangement. There's one catch, however: you must set up a few DNS records to distribute RSA public keys and (if applicable) IPsec gateway information.

If you start FreeS/WAN before you have set up these DNS records, your connectivity will be slow, and messages relating to the built in connections will clutter your logs. If you are unable to set up DNS for OE, you will wish to disable the hidden connections.

Upgrading Opportunistic Encryption to 2.01 (or later)

As of FreeS/WAN 2.01, Opportunistic Encryption (OE) uses DNS TXT resource records (RRs) only (rather than TXT with KEY). This change causes a "flag day". Users of FreeS/WAN 2.00 (or earlier) OE who are upgrading may need to post additional resource records.

If you are running initiate-only OE, you must put up a TXT record in any forward domain as per our quickstart instructions. This replaces your old forward KEY.

If you are running full OE, you require no updates. You already have the needed TXT record in the reverse domain. However, to facilitate future features, you may also wish to publish that TXT record in a forward domain as instructed here.

If you are running OE on a gateway (and encrypting on behalf of subnetted boxes) you require no updates. You already have the required TXT record in your gateway's reverse map, and the TXT records for any subnetted boxes require no updating. However, to facilitate future features, you may wish to publish your gateway's TXT record in a forward domain as shown here.

During the transition, you may wish to leave any old KEY records up for some time. They will provide limited backward compatibility.

New! Policy Groups

We want to make it easy for you to declare security policy as it applies to IPsec connections.

Policy Groups make it simple to say:

FreeS/WAN then implements these policies, creating OE connections if and when needed. You can use Policy Groups along with connections you explicitly define in ipsec.conf.

For more information, see our Policy Group HOWTO.

New! Packetdefault Connection

Free/SWAN 2.x ships with the automatically enabled, hidden connection packetdefault. This configures a FreeS/WAN box as an OE gateway for any hosts located behind it. As mentioned above, you must configure some DNS records for OE to work.

As the name implies, this connection functions as a default. If you have more specific connections, such as policy groups which configure your FreeS/WAN box as an OE gateway for a local subnet, these will apply before packetdefault. You can view packetdefault 's specifics in man ipsec.conf .

FreeS/WAN now disables Reverse Path Filtering

FreeS/WAN often doesn't work with reverse path filtering. At start time, FreeS/WAN now turns rp_filter off, and logs a warning.

FreeS/WAN does not turn it back on again. You can do this yourself with a command like:

   echo 1 > /proc/sys/net/ipv4/conf/eth0/rp_filter

For eth0, substitute the interface which FreeS/WAN was affecting.

Revised ipsec.conf

No promise of compatibility

The FreeS/WAN team promised config-file compatibility throughout the 1.x series. That means a 1.5 config file can be directly imported into a fresh 1.99 install with no problems.

With FreeS/WAN 2.x, we've given ourselves permission to make the config file easier to use. The cost: some FreeS/WAN 1.x configurations will not work properly. Many of the new features are, however, backward compatible.

Most ipsec.conf files will work fine

... so long as you paste this line, with no preceding whitespace, at the top of your config file:

    version 2

Backward compatibility patch

If the new defaults bite you, use this ipsec.conf fragment to simulate the old default values.

Details

We've obsoleted various directives which almost no one was using:

    dump
    plutobackgroundload
    no_eroute_pass
    lifetime
    rekeystart
    rekeytries

For most of these, there is some other way to elicit the desired behaviour. See this post.

We've made some settings, which almost everyone was using, defaults. For example:

    interfaces=%defaultroute
    plutoload=%search
    plutostart=%search
    uniqueids=yes

We've also changed some default values to help with OE and Policy Groups:

    authby=rsasig   ## not secret!!!
    leftrsasigkey=%dnsondemand ## looks up missing keys in DNS when needed.
    rightrsasigkey=%dnsondemand

Of course, you can still override any defaults by explictly declaring something else in your connection.

A post with a list of many ipsec.conf changes.
Current ipsec.conf manual.

Upgrading from 1.x RPMs to 2.x RPMs

Note: When upgrading from 1-series to 2-series RPMs, rpm -U will not work.

You must instead erase the 1.x RPMs, then install the 2.x set:

    rpm -e freeswan
    rpm -e freeswan-module

On erasing, your old ipsec.conf should be moved to ipsec.conf.rpmsave. Keep this. You will probably want to copy your existing connections to the end of your new 2.x file.

Install the RPMs suitable for your kernel version, such as:

    rpm -ivh freeswan-module-2.03_2.4.20_20.9-0.i386.rpm
    rpm -ivh freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

Or, to splice the files:

    cat /etc/ipsec.conf /etc/ipsec.conf.rpmsave > /etc/ipsec.conf.tmp
    mv /etc/ipsec.conf.tmp /etc/ipsec.conf

Then, remove the redundant conn %default and config setup sections. Unless you have done any special configuring here, you'll likely want to remove the 1.x versions. Remove conn OEself, if present.


Quickstart Guide to Opportunistic Encryption

Purpose

This page will get you started using Linux FreeS/WAN with opportunistic encryption (OE). OE enables you to set up IPsec tunnels without co-ordinating with another site administrator, and without hand configuring each tunnel. If enough sites support OE, a "FAX effect" occurs, and many of us can communicate without eavesdroppers.

OE "flag day"

As of FreeS/WAN 2.01, OE uses DNS TXT resource records (RRs) only (rather than TXT with KEY). This change causes a "flag day". Users of FreeS/WAN 2.00 (or earlier) OE who are upgrading may require additional resource records, as detailed in our upgrading document. OE setup instructions here are for 2.02 or later.

Requirements

To set up opportunistic encryption, you will need:

Note: Currently, only Linux FreeS/WAN supports opportunistic encryption.

RPM install

Our instructions are for a recent Red Hat with a 2.4-series stock or Red Hat updated kernel. For other ways to install, see our install document.

Download RPMs

If we have prebuilt RPMs for your Red Hat system, this command will get them:

    ncftpget ftp://ftp.xs4all.nl/pub/crypto/freeswan/binaries/RedHat-RPMs/`uname -r | tr -d 'a-wy-z'`/\*

If that fails, you will need to try another install method. Our kernel modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

If it succeeds, you will have userland tools, a kernel module, and an RPM signing key:

    freeswan-module-2.03_2.4.20_20.9-0.i386.rpm
    freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm
    freeswan-rpmsign.asc

Check signatures

If you're running RedHat 8.x or later, import the RPM signing key into the RPM database:

    rpm --import freeswan-rpmsign.asc

For RedHat 7.x systems, you'll need to add it to your PGP keyring:

    pgp -ka freeswan-rpmsign.asc

Check the digital signatures on both RPMs using:

    rpm --checksig freeswan*.rpm 

You should see that these signatures are good:

    freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
    freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

Install the RPMs

Become root:

    su

Install your RPMs with:

    rpm -ivh freeswan*.rpm

If you're upgrading from FreeS/WAN 1.x RPMs, and have problems with that command, see this note.

Then, start FreeS/WAN:

    service ipsec start

Test

To check that you have a successful install, run:

    ipsec verify

You should see as part of the verify output:

    Checking your system to see if IPsec got installed and started correctly
    Version check and ipsec on-path                             [OK]
    Checking for KLIPS support in kernel                        [OK]
    Checking for RSA private key (/etc/ipsec.secrets)           [OK]
    Checking that pluto is running                              [OK]
    ...

If any of these first four checks fails, see our troubleshooting guide.

Our Opportunistic Setups

Full or partial opportunism?

Determine the best form of opportunism your system can support.

Initiate-only setup

Restrictions

When you set up initiate-only Opportunistic Encryption (iOE):

You cannot network a group of initiator-only machines if none of these is capable of responding to OE. If one is capable of responding, you may be able to create a hub topology using routing.

Create and publish a forward DNS record

Find a domain you can use

Find a DNS forward domain (e.g. example.com) where you can publish your key. You'll need access to the DNS zone files for that domain. This is common for a domain you own. Some free DNS providers, such as this one, also provide this service.

Dynamic IP users take note: the domain where you place your key need not be associated with the IP address for your system, or even with your system's usual hostname.

Choose your ID

Choose a name within that domain which you will use to identify your machine. It's convenient if this can be the same as your hostname:

    [root@xy root]# hostname --fqdn
    xy.example.com

This name in FQDN (fully-qualified domain name) format will be your ID, for DNS key lookup and IPsec negotiation.

Create a forward TXT record

Generate a forward TXT record containing your system's public key with a command like:

    ipsec showhostkey --txt @xy.example.com

using your chosen ID in place of xy.example.com. This command takes the contents of /etc/ipsec.secrets and reformats it into something usable by ISC's BIND. The result should look like this (with the key data trimmed down for clarity):

    ; RSA 2192 bits   xy.example.com   Thu Jan  2 12:41:44 2003
        IN      TXT     "X-IPsec-Server(10)=@xy.example.com" 
    "AQOF8tZ2... ...+buFuFn/"

Publish the forward TXT record

Insert the record into DNS, or have a system adminstrator do it for you. It may take up to 48 hours for the record to propagate, but it's usually much quicker.

Test that your key has been published

Check your DNS work

    ipsec verify --host xy.example.com

As part of the verify output, you ought to see something like:

    ...
    Looking for TXT in forward map: xy.example.com          [OK]
    ...

For this type of opportunism, only the forward test is relevant; you can ignore the tests designed to find reverse records.

Configure, if necessary

If your ID is the same as your hostname, you're ready to go. FreeS/WAN will use its built-in connections to create your iOE functionality.

If you have chosen a different ID, you must tell FreeS/WAN about it via ipsec.conf:

    config setup
        myid=@myname.freedns.example.com

and restart FreeS/WAN:

    service ipsec restart

The new ID will be applied to the built-in connections.

Note: you can create more complex iOE configurations as explained in our policy groups document, or disable OE using these instructions.

Test

That's it! Test your connections.

Full Opportunism

Full opportunism allows you to initiate and receive opportunistic connections on your machine.

Put a TXT record in a Forward Domain

To set up full opportunism, first set up a forward TXT record as for initiator-only OE , using an ID (for example, your hostname) that resolves to your IP. Do not configure /etc/ipsec.conf, but continue with the instructions for full opportunism, below.

Note that this forward record is not currently necessary for full OE, but will facilitate future features.

Put a TXT record in Reverse DNS

You must be able to publish your DNS RR directly in the reverse domain. FreeS/WAN will not follow a PTR which appears in the reverse, since a second lookup at connection start time is too costly.

Create a Reverse DNS TXT record

This record serves to publicize your FreeS/WAN public key. In addition, it lets others know that this machine can receive opportunistic connections, and asserts that the machine is authorized to encrypt on its own behalf.

Use the command:

    ipsec showhostkey --txt 192.0.2.11

where you replace 192.0.2.11 with your public IP.

The record (with key shortened) looks like:

    ; RSA 2048 bits  xy.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"

Publish your TXT record

Send these records to your ISP, to be published in your IP's reverse map. It may take up to 48 hours for these to propagate, but usually takes much less time.

Test your DNS record

Check your DNS work with

    ipsec verify --host xy.example.com

As part of the verify output, you ought to see something like:

    ...
    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa [OK]
    ...

which indicates that you've passed the reverse-map test.

No Configuration Needed

FreeS/WAN 2.x ships with full OE enabled, so you don't need to configure anything. To enable OE out of the box, FreeS/WAN 2.x uses the policy group private-or-clear, which creates IPsec connections if possible (using OE if needed), and allows traffic in the clear otherwise. You can create more complex OE configurations as described in our policy groups document, or disable OE using these instructions .

If you've previously configured for initiator-only opportunism, remove myid= from config setup, so that peer FreeS/WANs will look up your key by IP. Restart FreeS/WAN so that your change will take effect, with

    service ipsec restart

Consider Firewalling

If you are running a default install of RedHat 8.x, take note: you will need to alter your iptables rule setup to allow IPSec traffic through your firewall. See our firewall document for sample iptables rules.

Test

That's it. Now, test your connection.

Test

Instructions are in the next section.

Testing opportunistic connections

Be sure IPsec is running. You can see whether it is with:

    ipsec setup status

If need be, you can restart it with:

    service ipsec restart

Load a FreeS/WAN test website from the host on which you're running FreeS/WAN. Note: the feds may be watching these sites. Type one of:

   links oetest.freeswan.org
   links oetest.freeswan.nl

A positive result looks like this:

   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
   gateway.example.com
     _________________________________________________________________

   Status E-route
   OE    enabled    16    192.139.46.73/32    ->    192.0.2.11/32   =>
   tun0x2097@192.0.2.11
   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
   tun0x208a@192.0.2.11

If you see this, congratulations! Your OE host or gateway will now encrypt its own traffic whenever it can. For more OE tests, please see our testing document. If you have difficulty, see our OE troubleshooting tips.

Now what?

Please see our policy groups document for more ways to set up Opportunistic Encryption.

You may also wish to make some pre-configured connections.

Notes

Troubleshooting OE

See the OE troubleshooting hints in our troubleshooting guide.

Known Issues

Please see this list of known issues with Opportunistic Encryption.


How to Configure Linux FreeS/WAN with Policy Groups

What are Policy Groups?

Policy Groups are an elegant general mechanism to configure FreeS/WAN. They are useful for many FreeS/WAN users.

In previous FreeS/WAN versions, you needed to configure each IPsec connection explicitly, on both local and remote hosts. This could become complex.

By contrast, Policy Groups allow you to set local IPsec policy for lists of remote hosts and networks, simply by listing the hosts and networks which you wish to have special treatment in one of several Policy Group files. FreeS/WAN then internally creates the connections needed to implement each policy.

In the next section we describe our five Base Policy Groups, which you can use to configure IPsec in many useful ways. Later, we will show you how to create an IPsec VPN using one line of configuration for each remote host or network.

Built-In Security Options

FreeS/WAN offers these Base Policy Groups:

private
FreeS/WAN only communicates privately with the listed CIDR blocks. If needed, FreeS/WAN attempts to create a connection opportunistically. If this fails, FreeS/WAN blocks communication. Inbound blocking is assumed to be done by the firewall. FreeS/WAN offers firewall hooks but no modern firewall rules to help with inbound blocking.
private-or-clear
FreeS/WAN prefers private communication with the listed CIDR blocks. If needed, FreeS/WAN attempts to create a connection opportunistically. If this fails, FreeS/WAN allows traffic in the clear.
clear-or-private
FreeS/WAN communicates cleartext with the listed CIDR blocks, but also accepts inbound OE connection requests from them. Also known as passive OE (pOE), this policy may be used to create an opportunistic responder.
clear
FreeS/WAN only communicates cleartext with the listed CIDR blocks.
block
FreeS/WAN blocks traffic to and from and the listed CIDR blocks. Inbound blocking is assumed to be done by the firewall. FreeS/WAN offers firewall hooks but no modern firewall rules to help with inbound blocking.

Notes:

Using Policy Groups

The Base Policy Groups which build IPsec connections rely on Opportunistic Encryption. To use the following examples, you must first become OE-capable, as described in our quickstart guide.

Example 1: Using a Base Policy Group

Simply place CIDR blocks (names, IPs or IP ranges) in /etc/ipsec.d/policies/[groupname], and reread the policy group files.

For example, the private-or-clear policy tells FreeS/WAN to prefer encrypted communication to the listed CIDR blocks. Failing that, it allows talk in the clear.

To make this your default policy, place fullnet in the private-or-clear policy group file:

    [root@xy root]# cat /etc/ipsec.d/policies/private-or-clear
    # This file defines the set of CIDRs (network/mask-length) to which
    # communication should be private, if possible, but in the clear otherwise.
    ....
    0.0.0.0/0

and reload your policies with

    ipsec auto --rereadgroups

Use this test to verify opportunistic connections.

Example 2: Defining IPsec Security Policy with Groups

Defining IPsec security policy with Base Policy Groups is like creating a shopping list: just put CIDR blocks in the appropriate group files. For example:

    [root@xy root]# cd /etc/ipsec.d/policies
    [root@xy policies]# cat private
        192.0.2.96/27              # The finance department
        192.0.2.192/29             # HR
	192.0.2.12                 # HR gateway
        irc.private.example.com    # Private IRC server
  
    [root@xy policies]# cat private-or-clear
        0.0.0.0/0                  # My default policy: try to encrypt.

    [root@xy policies]# cat clear
        192.0.2.18/32              # My POP3 server
        192.0.2.19/32              # My Web proxy

    [root@xy policies]# cat block
        spamsource.example.com

To make these settings take effect, type:

    ipsec auto --rereadgroups

Notes:

Example 3: Creating a Simple IPsec VPN with the private Group

You can create an IPsec VPN between several hosts, with only one line of configuration per host, using the private policy group.

First, use our quickstart guide to set up each participating host with a FreeS/WAN install and OE.

In one host's /etc/ipsec.d/policies/private, list the peers to which you wish to protect traffic. For example:

    [root@xy root]# cd /etc/ipsec.d/policies
    [root@xy policies]# cat private
        192.0.2.9              # several hosts at example.com
        192.0.2.11             
        192.0.2.12                 
        irc.private.example.com 

Copy the private file to each host. Remove the local host, and add the initial host.

    scp2 /etc/ipsec.d/policies/private root@192.0.2.12:/etc/ipsec.d/policies/private

On each host, reread the policy groups with

    ipsec auto --rereadgroups

That's it! You're configured.

Test by pinging between two hosts. After a second or two, traffic should flow, and

    ipsec eroute

should yield something like

    192.0.2.11/32   -> 192.0.2.8/32  => tun0x149f@192.0.2.8

where your host IPs are substituted for 192.0.2.11 and 192.0.2.8.

If traffic does not flow, there may be an error in your OE setup. Revisit our quickstart guide.

Our next two examples show you how to add subnets to this IPsec VPN.

Example 4: New Policy Groups to Protect a Subnet

To protect traffic to a subnet behind your FreeS/WAN gateway, you'll need additional DNS records, and new policy groups. To set up the DNS, see our quickstart guide. To create five new policy groups for your subnet, copy these connections to /etc/ipsec.conf. Substitute your subnet's IPs for 192.0.2.128/29.

conn private-net
    also=private  # inherits settings (eg. auto=start) from built in conn
    leftsubnet=192.0.2.128/29  # your subnet's IPs here

conn private-or-clear-net
    also=private-or-clear
    leftsubnet=192.0.2.128/29

conn clear-or-private-net
    also=clear-or-private
    leftsubnet=192.0.2.128/29

conn clear-net
    also=clear
    leftsubnet=192.0.2.128/29

conn block-net
    also=block
    leftsubnet=192.0.2.128/29

Copy the gateway's files to serve as the initial policy group files for the new groups:

    cp -p /etc/ipsec.d/policies/private /etc/ipsec.d/policies/private-net
    cp -p /etc/ipsec.d/policies/private-or-clear /etc/ipsec.d/policies/private-or-clear-net
    cp -p /etc/ipsec.d/policies/clear-or-private /etc/ipsec.d/policies/clear-or-private-net
    cp -p /etc/ipsec.d/policies/clear /etc/ipsec.d/policies/clear-net
    cp -p /etc/ipsec.d/policies/block /etc/ipsec.d/policies/block

Tip: Since a missing policy group file is equivalent to a file with no entries, you need only create files for the connections you'll use.

To test one of your new groups, place the fullnet 0.0.0.0/0 in private-or-clear-net. Perform the subnet test in our quickstart guide. You should see a connection, and

    ipsec eroute

should include an entry which mentions the subnet node's IP and the OE test site IP, like this:

    192.0.2.131/32   -> 192.139.46.77/32  => tun0x149f@192.0.2.11

Example 5: Adding a Subnet to the VPN

Suppose you wish to secure traffic to a subnet 192.0.2.192/29 behind a FreeS/WAN box 192.0.2.12.

First, add DNS entries to configure 192.0.2.12 as an opportunistic gateway for that subnet. Instructions are in our quickstart guide. Next, create a private-net group on 192.0.2.12 as described in Example 4.

On each other host, add the subnet 192.0.2.192/29 to private , yielding for example

    [root@xy root]# cd /etc/ipsec.d/policies
    [root@xy policies]# cat private
        192.0.2.9              # several hosts at example.com
        192.0.2.11
        192.0.2.12             # HR department gateway
        192.0.2.192/29         # HR subnet
        irc.private.example.com

and reread policy groups with

    ipsec auto --rereadgroups

That's all the configuration you need.

Test your VPN by pinging from a machine on 192.0.2.192/29 to any other host:

    [root@192.0.2.194]# ping 192.0.2.11

After a second or two, traffic should flow, and

    ipsec eroute

should yield something like

    192.0.2.11/32   -> 192.0.2.194/32  => tun0x149f@192.0.2.12

Key:

1.192.0.2.11/32Local start point of the protected traffic.
2.192.0.2.194/32Remote end point of the protected traffic.
3.192.0.2.12Remote FreeS/WAN node (gateway or host). May be the same as (2).
4.[not shown]Local FreeS/WAN node (gateway or host), where you've produced the output. May be the same as (1).

For additional assurance, you can verify with a packet sniffer that the traffic is being encrypted.

Note

Appendix

Our Hidden Connections

Our Base Policy Groups are created using hidden connections. These are spelled out in man ipsec.conf and defined in /usr/lib/ipsec/_confread.

Custom Policy Groups

A policy group is built using a special connection description in ipsec.conf, which:

To create a new group:

  1. Create its connection definition in ipsec.conf.
  2. Create a Policy Group file in /etc/ipsec.d/policies with the same name as your connection.
  3. Put a CIDR block in that file.
  4. Reread groups with ipsec auto --rereadgroups.
  5. Test: ping to activate any OE connection, and view results with ipsec eroute.

Disabling Opportunistic Encryption

To disable OE (eg. policy groups and packetdefault), cut and paste the following lines to /etc/ipsec.conf:

conn block
    auto=ignore

conn private
    auto=ignore

conn private-or-clear
    auto=ignore

conn clear-or-private
    auto=ignore

conn clear
    auto=ignore

conn packetdefault
    auto=ignore

Restart FreeS/WAN so that the changes take effect:

    ipsec setup restart

FreeS/WAN FAQ

This is a collection of questions and answers, mostly taken from the FreeS/WAN mailing list. See the project web site for more information. All the FreeS/WAN documentation is online there.

Contributions to the FAQ are welcome. Please send them to the project mailing list.


Index of FAQ questions


What is FreeS/WAN?

FreeS/WAN is a Linux implementation of the IPsec protocols, providing security services at the IP (Internet Protocol) level of the network.

For more detail, see our introduction document or the FreeS/WAN project web site.

To start setting it up, go to our quickstart guide.

Our web links document has information on IPsec for other systems.

How do I report a problem or seek help?

Read our troubleshooting document.

It may guide you to a solution. If not, see its problem reporting section.

Basically, what it says is give us the output from ipsec barf from both gateways. Without full information, we cannot diagnose a problem. However, ipsec barf produces a lot of output. If at all possible, please make barfs accessible via the web or FTP rather than sending enormous mail messages.

Use the users mailing list for problem reports, rather than mailing developers directly.
Try irc.freenode.net#freeswan.

FreeS/WAN developers, volunteers and users can often be found there. Be patient and be prepared to provide lots of information to support your question.

If your question was really interesting, and you found an answer, please share that with the class by posting to the users mailing list. That way others with the same problem can find your answer in the archives.

Premium support is also available.

See the next several questions.

Can I get ...

Can I get an off-the-shelf system that includes FreeS/WAN?

There are a number of Linux distributions or firewall products which include FreeS/WAN. See this list. Using one of these, chosen to match your requirements and budget, may save you considerable time and effort.

If you don't know your requirements, start by reading Schneier's Secrets and Lies. That gives the best overview of security issues I have seen. Then consider hiring a consultant (see next question) to help define your requirements.

Can I hire consultants or staff who know FreeS/WAN?

If you want the help of a contractor, or to hire staff with FreeS/WAN expertise, you could:

For companies offerring support, see the next question.

Can I get commercial support?

Many of the distributions or firewall products which include FreeS/WAN (see this list) come with commercial support or have it available as an option.

Various companies specialize in commercial support of open source software. Our project leader was a founder of the first such company, Cygnus Support. It has since been bought by Redhat. Another such firm is Linuxcare.

Release questions

What is the current release?

The current release is the highest-numbered tarball on our distribution site. Almost always, any of the mirrors will have the same file, though perhaps not for a day or so after a release.

Unfortunately, the web site is not always updated as quickly as it should be.

When is the next release?

We try to do a release approximately every six to eight weeks.

If pre-release tests fail and the fix appears complex, or more generally if the code does not appear stable when a release is scheduled, we will just skip that release.

For serious bugs, we may bring out an extra bug-fix release. These get numbers in the normal release series. For example, there was a bug found in FreeS/WAN 1.6, so we did another release less than two weeks later. The bug-fix release was called 1.7.

Are there known bugs in the current release?

Any problems we are aware of at the time of a release are documented in the BUGS file for that release. You should also look at the CHANGES file.

Bugs discovered after a release are discussed on the mailing lists. The easiest way to check for any problems in the current code would be to peruse the List In Brief.

Modifications and contributions

Can I modify FreeS/WAN to ...?

You are free to modify FreeS/WAN in any way. See the discussion of licensing in our introduction document.

Before investing much energy in any such project, we suggest that you

This may prevent duplicated effort, or lead to interesting collaborations.

Can I contribute to the project?

In general, we welcome contributions from the community. Various contributed patches, either to fix bugs or to add features, have been incorporated into our distribution. Other patches, not yet included in the distribution, are listed in our web links section.

Users have also contributed heavily to documentation, both by creating their own HowTos and by posting things on the mailing lists which I have quoted in these HTML docs.

There are, however, some caveats.

FreeS/WAN is being implemented in Canada, by Canadians, largely to ensure that is it is entirely free of export restrictions. See this discussion. We cannot accept code contributions from US residents or citizens, not even one-line bugs fixes. The reasons for this were recently discussed extensively on the mailing list, in a thread starting here.

Not all contributions are of interest to us. The project has a set of fairly ambitious and quite specific goals, described in our introduction. Contributions that lead toward these goals are likely to be welcomed enthusiastically. Other contributions may be seen as lower priority, or even as a distraction.

Discussion of possible contributions takes place on the design mailing list.

Is there detailed design documentation?

There are:

The only formal design documents are a few papers in the last category above. All the other categories, however, have things to say about design as well.

Will FreeS/WAN work in my environment?

Can FreeS/WAN talk to ...?

The IPsec protocols are designed to support interoperation. In theory, any two IPsec implementations should be able to talk to each other. In practice, it is considerably more complex. We have a whole interoperation document devoted to this problem.

An important part of that document is links to the many user-written HowTos on interoperation between FreeS/WAN and various other implementations. Often the users know more than the developers about these issues (and almost always more than me :-), so these documents may be your best resource.

Can different FreeS/WAN versions talk to each other?

Linux FreeS/WAN can interoperate with many IPsec implementations, including earlier versions of Linux FreeS/WAN itself.

In a few cases, there are some complications. See our interoperation document for details.

Is there a limit on throughput?

There is no hard limit, but see below.

Is there a limit on number of tunnels?

There is no hard limit, but see next question.

Is a ... fast enough to handle FreeS/WAN with my loads?

A quick summary:

Even a limited machine can be useful
A 486 can handle a T1, ADSL or cable link, though the machine may be breathing hard.
A mid-range PC (say 800 MHz with good network cards) can do a lot of IPsec
With up to roughly 50 tunnels and aggregate bandwidth of 20 Megabits per second, it willl have cycles left over for other tasks.
There are limits
Even a high end CPU will not come close to handling a fully loaded 100 Mbit/second Ethernet link.

Beyond about 50 tunnels it needs careful management.

See our FreeS/WAN performance document for details.

Will FreeS/WAN work on ... ?

Will FreeS/WAN run on my version of Linux?

We build and test on Redhat distributions, but FreeS/WAN runs just fine on several other distributions, sometimes with minor fiddles to adapt to the local environment. Details are in our compatibility document. Also, some distributions or products come with FreeS/WAN included.

Will FreeS/WAN run on non-Intel CPUs?

FreeS/WAN is intended to run on all CPUs Linux supports . We know of it being used in production on x86, ARM, Alpha and MIPS. It has also had successful tests on PPC and SPARC, though we don't know of actual use there. Details are in our compatibility document.

Will FreeS/WAN run on multiprocessors?

FreeS/WAN is designed to work on any SMP architecture Linux supports, and has been tested successfully on at least dual processor Intel architecture machines. Details are in our compatibility document.

Will FreeS/WAN work on an older kernel?

It might, but we strongly recommend using a recent 2.2 or 2.4 series kernel. Sometimes the newer versions include security fixes which can be quite important on a gateway.

Also, we use recent kernels for development and testing, so those are better tested and, if you do encounter a problem, more easily supported. If something breaks applying recent FreeS/WAN patches to an older kernel, then "update your kernel" is almost certain to be the first thing we suggest. It may be the only suggestion we have.

The precise kernel versions supported by a particular FreeS/WAN release are given in the README file of that release.

See the following question for more on kernels.

Will FreeS/WAN run on the latest kernel version?

Sometimes yes, but quite often, no.

Kernel versions supported are given in the README file of each FreeS/WAN release. Typically, they are whatever production kernels were current at the time of our release (or shortly before; we might release for kernel n just as Linus releases n+1 ). Often FreeS/WAN will work on slightly later kernels as well, but of course this cannot be guaranteed.

For example, FreeS/WAN 1.91 was released for kernels 2.2.19 or 2.4.5, the current kernels at the time. It also worked on 2.4.6, 2.4.7 and 2.4.8, but 2.4.9 had changes that caused compilation errors if it was patched with FreeS/WAN 1.91.

When such changes appear, we put a fix in the FreeS/WAN snapshots, and distribute it with our next release. However, this is not a high priority for us, and it may take anything from a few days to several weeks for such a problem to find its way to the top of our kernel programmer's To-Do list. In the meanwhile, you have two choices:

We don't even try to keep up with kernel changes outside the main 2.2 and 2.4 branches, such as the 2.4.x-ac patched versions from Alan Cox or the 2.5 series of development kernels. We'd rather work on developing the FreeS/WAN code than on chasing these moving targets. We are, however, happy to get patches for problems discovered there.

See also the Choosing a kernel section of our installation document.

Will FreeS/WAN work on unusual network hardware?

IPsec is designed to work over any network that IP works over, and FreeS/WAN is intended to work over any network interface hardware that Linux supports.

If you have working IP on some unusual interface -- perhaps Arcnet, Token Ring, ATM or Gigabit Ethernet -- then IPsec should "just work".

That said, practice is sometimes less tractable than theory. Our testing is done almost entirely on:

If you have some other interface, especially an uncommon one, it is entirely possible you will get bitten either by a FreeS/WAN bug which our testing did not turn up, or by a bug in the driver that shows up only with our loads.

If IP works on your interface and FreeS/WAN doesn't, seek help on the mailing lists.

Another FAQ section describes MTU problems . These are a possibility for some interfaces.

Will FreeS/WAN work on a VLAN (802.1q) network?

Yes, FreeSwan works fine, though some network drivers have problems with jumbo sized ethernet frames. If you used interfaces=%defaultroute you do not need to change anything, but if you specified an interface (eg eth0) then remember you must change that to reflect the VLAN interface (eg eth0.2 for VLAN ID 2).

The "eepro100" module is known to be broken, use the e100 driver for those cards instead (included in 2.4 as 'alternative driver' for the Intel EtherExpressPro/100.

You do not need to change any MTU setting (those are workarounds that are only needed for buggy drivers)

This FAQ contributed by Paul Wouters.

Does FreeS/WAN support ...

For a discussion of which parts of the IPsec specifications FreeS/WAN does and does not implement, see our compatibility document.

For information on some often-requested features, see below.

Does FreeS/WAN support site-to-site VPN ( Virtual Private Network) applications?

Absolutely. See this FreeS/WAN-FreeS/WAN configuration example. If only one site is using FreeS/WAN, there may be a relevant HOWTO on our interop page.

Does FreeS/WAN support remote users connecting to a LAN?

Yes. We call the remote users "Road Warriors". Check out our FreeS/WAN-FreeS/WAN Road Warrior Configuration Example.

If your Road Warrior is a Windows or Mac PC, you may need to install an IPsec implementation on that machine. Our interop page lists many available brands, and features links to several HOWTOs.

Does FreeS/WAN support remote users using shared secret authentication?

Yes, but there are severe restrictions, so we strongly recommend using RSA keys for authentication instead.

See this FAQ question.

Does FreeS/WAN support wireless networks?

Yes, it is a common practice to use IPsec over wireless networks because their built-in encryption, WEP, is insecure.

There is some discussion in our advanced configuration document. See also the WaveSEC site.

Does FreeS/WAN support X.509 or other PKI certificates?

Vanilla FreeS/WAN does not support X.509, but Andreas Steffen and others have provided a popular, well-supported X.509 patch.

Linux FreeS/WAN features Opportunistic Encryption, an alternative Public Key Infrastructure based on Secure DNS.

Does FreeS/WAN support user authentication (Radius, SecureID, Smart Card...)?

Andreas Steffen's X.509 patch (v. 1.42+) supports Smart Cards. The patch does not ship with vanilla FreeS/WAN, but will be incorporated into Super FreeS/WAN 2.01+. The patch implements the PCKS#15 Cryptographic Token Information Format Standard, using the OpenSC smartcard library functions.

Older news:

A user-supported patch to FreeS/WAN 1.3, for smart card style authentication, is available on Bastiaan's site. It supports skeyid and ibutton. This patch is not part of Super FreeS/WAN.

For a while progress on this front was impeded by a lack of standard. The IETF working group has now nearly completed its recommended solution to the problem; meanwhile several vendors have implemented various things.

Of course, there are various ways to avoid any requirement for user authentication in IPsec. Consider the situation where road warriors build IPsec tunnels to your office net and you are considering requiring user authentication during tunnel negotiation. Alternatives include:

If either of those is trustworthy, it is not clear that you need user authentication in IPsec.

Does FreeS/WAN support NAT traversal?

Vanilla FreeS/WAN does not, but thanks to Mathieu Lafon and Arkoon Network Security, there's a patch to support this.

The NAT traversal patch has some issues with PSKs, so you may wish to authenticate with RSA keys, or X.509 (requires a patch which is also included in Super FreeS/WAN). Doing the latter also has advantages when dealing with large numbers of clients who may be behind NAT; instead of having to make an individual Roadwarrior connection for each virtual IP, you can use the "rightsubnetwithin" parameter to specify a range. See these rightsubnetwithin instructions.

Does FreeS/WAN support assigning a "virtual identity" to a remote system?

Some IPsec implementations allow you to make the source address on packets sent by a Road Warrior machine be something other than the address of its interface to the Internet. This is sometimes described as assigning a virtual identity to that machine.

FreeS/WAN does not directly support this, but it can be done. See this FAQ question.

Does FreeS/WAN support single DES encryption?

No, single DES is not used either at the IKE level for negotiating connections or at the IPsec level for actually building them.

Single DES is insecure. As we see it, it is more important to deliver real security than to comply with a standard which has been subverted into allowing use of inadequate methods. See this discussion.

If you want to interoperate with an IPsec implementation which offers only DES, see our interoperation document.

Does FreeS/WAN support AES encryption?

AES is a new US government block cipher standard to replace the obsolete DES.

At time of writing (March 2002), the FreeS/WAN distribution does not yet support AES but user-written patches are available to add it. Our kernel programmer is working on integrating those patches into the distribution, and there is active discussion of this on the design mailimg list.

Does FreeS/WAN support other encryption algorithms?

Currently triple DES is the only cipher supported. AES will almost certainly be added (see previous question), and it is likely that in the process we will also add the other two AES finalists with open licensing, Twofish and Serpent.

We are extremely reluctant to add other ciphers. This would make both use and maintenance of FreeS/WAN more complex without providing any clear benefit. Complexity is emphatically not desirable in a security product.

Various users have written patches to add other ciphers. We provide links to these.

Can I ...

Can I use policy groups along with explicitly configured connections?

Yes, you can, so long as you pay attention to the selection rule, which can be summarized "the most specific connection wins". We describe the rule in our policy groups document, and provide a more technical explanation in man ipsec.conf.

A good guideline: If you have a regular connection defined in ipsec.conf, ensure that a subset of that connection is not listed in a less restrictive policy group. Otherwise, FreeS/WAN will use the subset, with its more specific source/destination pair.

Here's an example. Suppose you are the system administrator at 192.0.2.2. You have this connection in ipsec.conf: ipsec.conf :

conn net-to-net
    left=192.0.2.2           # you are here
    right=192.0.2.8
    rightsubnet=192.0.2.96/27
    ....

If you then place a host or net within rightsubnet, (let's say 192.0.2.98) in private-or-clear, you may find that 192.0.2.2 at times communicates in the clear with 192.0.2.98. That's consistent with the rule, but may be contrary to your expectations.

On the other hand, it's safe to put a larger subnet in a less restrictive policy group file. If private-or-clear contains 192.0.2.0/24, then the more specific net-to-net connection is used for any communication to 192.0.2.96/27. The more general policy applies only to communication with hosts or subnets in 192.0.2.0/24 without a more specific policy or connection.

Can I turn off policy groups?

Yes. Use these instructions.

Can I reload connection info without restarting?

Yes, you can do this. Here are the details, in a mailing list message from Pluto programmer Hugh Redelmeier:

| How can I reload config's without restarting all of pluto and klips?  I am using
| FreeSWAN -> PGPNet in a medium sized production environment, and would like to be
| able to add new connections ( i am using include config/* ) without dropping current
| SA's.
| 
| Can this be done?
| 
| If not, are there plans to add this kind of feature?

        ipsec auto --add whatever
This will look in the usual place (/etc/ipsec.conf) for a conn named
whatever and add it.

If you added new secrets, you need to do
        ipsec auto --rereadsecrets
before Pluto needs to know those secrets.

| I have looked (perhaps not thoroughly enough tho) to see how to do this:

There may be more bits to look for, depending on what you are trying
to do.

Another useful command here is ipsec auto --replace <conn_name> which re-reads data for a named connection.

Can I use several masqueraded subnets?

Yes. This is done all the time. See the discussion in our setup document. The only restriction is that the subnets on the two ends must not overlap. See the next question.

Here is a mailing list message on the topic. The user incorrectly thinks you need a 2.4 kernel for this -- actually various people have been doing it on 2.0 and 2.2 for quite some time -- but he has it right for 2.4.

Subject: Double NAT and freeswan working :)
   Date: Sun, 11 Mar 2001
   From: Paul Wouters <paul@xtdnet.nl>

Just to share my pleasure, and make an entry for people who are searching
the net on how to do this. Here's the very simple solution to have a double
NAT'ed network working with freeswan. (Not sure if this is old news, but I'm
not on the list (too much spam) and I didn't read this in any HOWTO/FAQ/doc
on the freeswan site yet (Sandy, put it in! :)

10.0.0.0/24 --- 10.0.0.1 a.b.c.d  ---- a.b.c.e {internet} ----+
                                                              |
10.0.1.0/24 --- 10.0.1.1 f.g.h.i  ---- f.g.h.j {internet} ----+

the goal is to have the first network do a VPN to the second one, yet also
have NAT in place for connections not destinated for the other side of the
NAT. Here the two Linux security gateways have one real IP number (cable
modem, dialup, whatever.

The problem with NAT is you don't want packets from 10.*.*.* to 10.*.*.*
to be NAT'ed. While with Linux 2.2, you can't, with Linux 2.4 you can.

(This has been tested and works for 2.4.2 with Freeswan snapshot2001mar8b)

relevant parts of /etc/ipsec.conf:

        left=f.g.h.i
        leftsubnet=10.0.1.0/24
        leftnexthop=f.g.h.j
        leftfirewall=yes
        leftid=@firewall.netone.nl
        leftrsasigkey=0x0........
        right=a.b.c.d
        rightsubnet=10.0.0.0/24
        rightnexthop=a.b.c.e
        rightfirewall=yes
        rightid=@firewall.nettwo.nl
        rightrsasigkey=0x0......
        # To authorize this connection, but not actually start it, at startup,
        # uncomment this.
        auto=add

and now the real trick. Setup the NAT correctly on both sites:

iptables -t nat -F
iptables -t nat -A POSTROUTING -o eth0 -d \! 10.0.0.0/8 -j MASQUERADE

This tells the NAT code to only do NAT for packets with destination other then
10.* networks. note the backslash to mask the exclamation mark to protect it
against the shell.

Happy painting :)

Paul

Can I use subnets masqueraded to the same addresses?

No. The notion that IP addresses are unique is one of the fundamental principles of the IP protocol. Messing with it is exceedingly perilous.

Fairly often a situation comes up where a company has several branches, all using the same non-routable addresses, perhaps 192.168.0.0/24. This works fine as long as those nets are kept distinct. The IP masquerading on their firewalls ensures that packets reaching the Internet carry the firewall address, not the private address.

This can break down when IPsec enters the picture. FreeS/WAN builds a tunnel that pokes through both masquerades and delivers packets from leftsubnet to rightsubnet and vice versa. For this to work, the two subnets must be distinct.

There are several solutions to this problem.

Usually, you re-number the subnets. Perhaps the Vancouver office becomes 192.168.101.0/24, Calgary 192.168.102.0/24 and so on. FreeS/WAN can happily handle this. With, for example leftsubnet=192.168.101.0/24 and rightsubnet=192.168.102.0/24 in a connection description, any machine in Calgary can talk to any machine in Vancouver. If you want to be more restrictive and use something like leftsubnet=192.168.101.128/25 and rightsubnet=192.168.102.240/28 so only certain machines on each end have access to the tunnel, that's fine too.

You could also split the subnet into smaller ones, for example using 192.168.1.0/25 in Vancouver and rightsubnet=192.168.0.128/25 in Calgary.

Alternately, you can just give up routing directly to machines on the subnets. Omit the leftsubnet and rightsubnet parameters from your connection descriptions. Your IPsec tunnels will then run between the public interfaces of the two firewalls. Packets will be masqueraded both before they are put into tunnels and after they emerge. Your Vancouver client machines will see only one Calgary machine, the firewall.

Can I assign a road warrior an address on my net (a virtual identity)?

Often it would be convenient to be able to give a Road Warrior an IP address which appears to be on the local network. Some IPsec implementations have support for this, sometimes calling the feature "virtual identity".

Currently (Sept 2002) FreeS/WAN does not support this, and we have no definite plans to add it. The difficulty is that is not yet a standard mechanism for it. There is an Internet Draft for a method of doing it using DHCP which looks promising. FreeS/WAN may support that in a future release.

In the meanwhile, you can do it yourself using the Linux iproute2(8) facilities. Details are in this paper.

Another method has also been discussed on the mailing list.:

For example, you might have:

leftsubnet=a.b.c.0/25
head office network
rightsubnet=a.b.c.129/32
extruded to a road warrior. Note that this is not in a.b.c.0/25
a.b.c.0/24
whole network, including both the above

You then set up routing so that the office machines use the IPsec gateway as their route to a.b.c.128/25. The leftsubnet parameter tells the road warriors to use tunnels to reach a.b.c.0/25, so you should have two-way communication. Depending or your network and applications, there may be some additional work to do on DNS or Windows configuration

Can I support many road warriors with one gateway?

Yes. This is easily done, using

either RSA authentication
standard in the FreeS/WAN distribution
or X.509 certificates
requires Super FreeS/WAN or a patch.

In either case, each Road Warrior must have a different key or certificate.

It is also possible using pre-shared key authentication, though we don't recommend this; see the next question for details.

If you expect to have more than a few dozen Road Warriors connecting simultaneously, you may need a fairly powerful gateway machine. See our document on FreeS/WAN performance.

Can I have many road warriors using shared secret authentication?

Yes, but avoid it if possible.

You can have multiple Road Warriors using shared secret authentication only if they all use the same secret. You must also set:

   uniqueids=no   

in the connection definition.

Why it's less secure:

This is a designed-in limitation of the IKE key negotiation protocol, not a problem with our implementation.

We very strongly recommend that you avoid using shared secret authentication for multiple Road Warriors. Use RSA authentication instead.

The longer story: When using shared secrets, the protocol requires that the responding gateway be able to determine which secret to use at a time when all it knows about the initiator is an IP address. This works fine if you know the initiator's address in advance and can use it to look up the appropiriate secret. However, it fails for Road Warriors since the gateway cannot know their IP addresses in advance.

With RSA signatures (or certificates) the protocol is slightly different. The initiator provides an identifier early in the exchange and the responder can use that identifier to look up the correct key or certificate. See above.

Can I use Quality of Service routing with FreeS/WAN?

From project technical lead Henry Spencer:

> Do QoS add to FreeS/WAN?
> For example integrating DiffServ and FreeS/WAN?

With a current version of FreeS/WAN, you will have to add hidetos=no to
the config-setup section of your configuration file.  By default, the TOS
field of tunnel packets is zeroed; with hidetos=no, it is copied from the
packet inside.  (This is a modest security hole, which is why it is no
longer the default.)

DiffServ does not interact well with tunneling in general.  Ways of
improving this are being studied.

Copying the TOS (type of service) information from the encapsulated packet to the outer header reveals the TOS information to an eavesdropper. This does not tell him much, but it might be of use in traffic analysis. Since we do not have to give it to him, our default is not to.

Even with the TOS hidden, you can still:

See ipsec.conf(5) for more on the hidetos= parameter.

Can I recognise dead tunnels and shut them down?

There is no general mechanism to do this is in the IPsec protocols.

From time to time, there is discussion on the IETF Working Group mailing list of adding a "keep-alive" mechanism (which some say should be called "make-dead"), but it is a fairly complex problem and no consensus has been reached on whether or how it should be done.

The protocol does have optional delete-SA messages which one side can send when it closes a connection in hopes this will cause the other side to do the same. FreeS/WAN does not currently support these. In any case, they would not solve the problem since:

However, connections do have limited lifetimes and you can control how many attempts your gateway makes to rekey before giving up. For example, you can set:

conn default
        keyingtries=3
        keylife=30m

With these settings old connections will be cleaned up. Within 30 minutes of the other end dying, rekeying will be attempted. If it succeeds, the new connection replaces the old one. If it fails, no new connection is created. Either way, the old connection is taken down when its lifetime expires.

Here is a mailing list message on the topic from FreeS/WAN tech support person Claudia Schmeing:

You ask how to determine whether a tunnel is redundant:

> Can anybody explain the best way to determine this. Esp when a RW has
> disconnected? I thought 'ipsec auto --status' might be one way.

If a tunnel goes down from one end, Linux FreeS/WAN on the
other end has no way of knowing this until it attempts to rekey.
Once it tries to rekey and fails, it will 'know' that the tunnel is 
down.

Because it doesn't have a way of knowing the state until this point, 
it will also not be able to tell you the state via ipsec auto --status.

> However, comparing output from a working tunnel with that of one that
> was closed 
> did not show clearly show tunnel status.

If your tunnel is down but not 'unrouted' (see man ipsec_auto), you
should not be able to ping the opposite side of the tunnel. You can
use this as an indicator of tunnel status.

On a related note, you may be interested to know that as of 1.7, 
redundant tunnels caused by RW disconnections are likely to be 
less of a pain. From doc/CHANGES:

    There is a new configuration parameter, uniqueids, to control a new Pluto
    option:  when a new connection is negotiated with the same ID as an old
    one, the old one is deleted immediately.  This should help eliminate
    dangling Road Warrior connections when the same Road Warrior reconnects. 
    It thus requires that IDs not be shared by hosts (a previously legal but
    probably useless capability).  NOTE WELL:  the sample ipsec.conf now has
    uniqueids=yes in its config-setup section.


Cheers,

Claudia

Can I build IPsec tunnels over a demand-dialed link?

This is possible, but not easy. FreeS/WAN technical lead Henry Spencer wrote:

> 5. If the ISDN link goes down in between and is reestablished, the SAs
> are still up but the eroute are deleted and the IPsec interface shows
> garbage (with ifconfig)
> 6. Only restarting IPsec will bring the VPN back online.

This one is awkward to solve.  If the real interface that the IPsec
interface is mounted on goes down, it takes most of the IPsec machinery
down with it, and a restart is the only good way to recover. 

The only really clean fix, right now, is to split the machines in two: 

1. A minimal machine serves as the network router, and only it is aware
that the link goes up and down. 

2. The IPsec is done on a separate gateway machine, which thinks it has
a permanent network connection, via the router.

This is clumsy but it does work.  Trying to do both functions within a
single machine is tricky.  There is a software package (diald) which will
give the illusion of a permanent connection for demand-dialed modem
connections; I don't know whether it's usable for ISDN, or whether it can
be made to cooperate properly with FreeS/WAN. 

Doing a restart each time the interface comes up *does* work, although it
is a bit painful.  I did that with PPP when I was running on a modem link;
it wasn't hard to arrange the PPP scripts to bring IPsec up and down at
the right times.  (I'd meant to investigate diald but never found time.)

In principle you don't need to do a complete restart on reconnect, but you
do have to rebuild some things, and we have no nice clean way of doing
only the necessary parts.

In the same thread, one user commented:

Subject: Re: linux-ipsec: IPsec and Dial Up Connections
   Date: Wed, 22 Nov 2000
   From: Andy Bradford <andyb@calderasystems.com>

On Wed, 22 Nov 2000 19:47:11 +0100, Philip Reetz wrote:

> Are there any ideas what might be the cause of the problem and any way
> to work around it.
> Any help is highly appreciated.

On my laptop, when using ppp there is a ip-up script in /etc/ppp that 
will be executed each time that the ppp interface is brought up.  
Likewise there is an ip-down script that is called when it is taken 
down.  You might consider custimzing those to stop and start FreeS/WAN 
with each connection.  I believe that ISDN uses the same files, though 
I could be wrong---there should be something similar though.

Can I build GRE, L2TP or PPTP tunnels over IPsec?

Yes. Normally this is not necessary, but it is useful in a few special cases. For example, if you must route non-IP packets such as IPX, you will need to use a tunneling protocol that can route these packets. IPsec can be layered around it for extra security. Another example: you can provide failover protection for high availability (HA) environments by combining IPsec with other tools. Ken Bantoft describes one such setup in Using FreeS/WAN with Linux-HA, GRE, OSPF and BGP for enterprise grade VPN solutions.

GRE over IPsec is covered as part of that document. Here are links to other GRE resources. Jacco de Leuw has created this page on L2TP over IPsec with instructions for FreeS/WAN and several other brands of IPsec software.

Please let us know of other useful links via the mailing lists.

... use Network Neighborhood (Samba, NetBIOS) over IPsec?

Your local PC needs to know how to translate NetBIOS names to IP addresses. It may do this either via a local LMHOSTS file, or using a local or remote WINS server. The WINS server is preferable since it provides a centralized source of the information to the entire network. To use a WINS server over the VPN (or any IP-based network), you must enable "NetBIOS over TCP".

Samba can emulate a WINS server on Linux.

See also several discussions in our September 2002 Users archives

Life's little mysteries

FreeS/WAN is a fairly complex product. (Neither the networks it runs on nor the protocols it uses are simple, so it could hardly be otherwise.) It therefore sometimes exhibits behaviour which can be somewhat confusing, or has problems which are not easy to diagnose. This section tries to explain those problems.

Setup and configuration of FreeS/WAN are covered in other documentation sections:

However, we also list some of the commonest problems here.

I cannot ping ....

This question is dealt with in the advanced configuration section under the heading multiple tunnels.

The standard subnet-to-subnet tunnel protects traffic only between the subnets. To test it, you must use pings that go from one subnet to the other.

For example, suppose you have:

      subnet a.b.c.0/24
             |
      eth1 = a.b.c.1
         gate1
      eth0 = 192.0.2.8
             |

       ~ internet ~

             |
      eth0 = 192.0.2.11
         gate2
      eth1 = x.y.z.1
              |
       subnet x.y.z.0/24

and the connection description:

conn abc-xyz
     left=192.0.2.8
     leftsubnet=a.b.c.0/24
     right=192.0.2.11
     rightsubnet=x.y.z.0/24

You can test this connection description only by sending a ping that will actually go through the tunnel. Assuming you have machines at addresses a.b.c.2 and x.y.z.2, pings you might consider trying are:

ping from x.y.z.2 to a.b.c.2 or vice versa
Succeeds if tunnel is working. This is the only valid test of the tunnel.
ping from gate2 to a.b.c.2 or vice versa
Does not use tunnel. gate2 is not on protected subnet.
ping from gate1 to x.y.z.2 or vice versa
Does not use tunnel. gate1 is not on protected subnet.
ping from gate1 to gate2 or vice versa
Does not use tunnel. Neither gate is on a protected subnet.

Only the first of these is a useful test of this tunnel. The others do not use the tunnel. Depending on other details of your setup and routing, they:

In some cases, you may be able to get around this. For the example network above, you could use:

        ping -I a.b.c.1 x.y.z.1

Both the adresses given are within protected subnets, so this should go through the tunnel.

If required, you can build additional tunnels so that all the machines involved can talk to all the others. See multiple tunnels in the advanced configuration document for details.

It takes forever to ...

Users fairly often report various problems involving long delays, sometimes on tunnel setup and sometimes on operations done through the tunnel, occasionally on simple things like ping or more often on more complex operations like doing NFS or Samba through the tunnel.

Almost always, these turn out to involve failure of a DNS lookup. The timeouts waiting for DNS are typically set long so that you won't time out when a query involves multiple lookups or long paths. Genuine failures therefore produce long delays before they are detected.

A mailing list message from project technical lead Henry Spencer:

> ... when i run /etc/rc.d/init.d/ipsec start, i get:
> ipsec_setup: Starting FreeS/WAN IPsec 1.5...
> and it just sits there, doesn't give back my bash prompt.

Almost certainly, the problem is that you're using DNS names in your
ipsec.conf, but DNS lookups are not working for some reason.  You will
get your prompt back... eventually.  But the DNS timeouts are long.
Doing something about this is on our list, but it is not easy.

In the meanwhile, we recommend that connection descriptions in ipsec.conf(5) use numeric IP addresses rather than names which will require a DNS lookup.

Names that do not require a lookup are fine. For example:

These are fine. The @ sign prevents any DNS lookup. However, do not attempt to give the gateway address as left=camelot.example.org . That requires a lookup.

A post from one user after solving a problem with long delays:

Subject: Final Answer to Delay!!!
   Date: Mon, 19 Feb 2001
   From: "Felippe Solutions" <felippe@solutionstecnologia.com.br>

Sorry people, but seems like the Delay problem had nothing to do with
freeswan.

The problem was DNS as some people sad from the beginning, but not the way
they thought it was happening. Samba, ssh, telnet and other apps try to
reverse lookup addresses when you use IP numbers (Stupid that ahh).

I could ping very fast because I always ping with "-n" option, but I don't
know the option on the other apps to stop reverse addressing so I don't use
it.

This post is fairly typical. These problems are often tricky and frustrating to diagnose, and most turn out to be DNS-related.

One suggestion for diagnosis: test with both names and addresses if possible. For example, try all of:

If these behave differently, the problem must be DNS-related since the three commands do exactly the same thing except for DNS lookups.

I send packets to the tunnel with route(8) but they vanish

IPsec connections are designed to carry only packets travelling between pre-defined connection endpoints. As project technical lead Henry Spencer put it:

IPsec tunnels are not just virtual wires; they are virtual wires with built-in access controls. Negotiation of an IPsec tunnel includes negotiation of access rights for it, which don't include packets to/from other IP addresses. (The protocols themselves are quite inflexible about this, so there are limits to what we can do about it.)

For fairly obvious security reasons, and to comply with the IPsec RFCs, KLIPS drops any packets it receives that are not allowed on the tunnels currently defined. So if you send it packets with route(8), and suitable tunnels are not defined, the packets vanish. Whether this is reported in the logs depends on the setting of klipsdebug in your ipsec.conf(5) file.

To rescue vanishing packets, you must ensure that suitable tunnels for them exist, by editing the connection descriptions in ipsec.conf(5). For example, supposing you have a simple setup:

         leftsubnet -- leftgateway === internet === roadwarrior

If you want to give the roadwarrior access to some resource that is located behind the left gateway but is not in the currently defined left subnet, then the usual procedure is to define an additional tunnel for those packets by creating a new connection description.

In some cases, it may be easier to alter an existing connection description, enlarging the definition of leftsubnet. For example, instead of two connection descriptions with 192.168.8.0/24 and 192.168.9.0/24 as their leftsubnet parameters, you can use a single description with 192.168.8.0/23.

If you have multiple endpoints on each side, you need to ensure that there is a route for each pair of endpoints. See this example.

When a tunnel goes down, packets vanish

This is a special case of the vanishing packet problem described in the previous question. Whenever KLIPS sees packets for which it does not have a tunnel, it drops them.

When a tunnel goes away, either because negotiations with the other gateway failed or because you gave an ipsec auto --down command, the route to its other end is left pointing into KLIPS, and KLIPS will drop packets it has no tunnel for.

This is a documented design decision, not a bug. FreeS/WAN must not automatically adjust things to send packets via another route. The other route might be insecure.

Of course, re-routing may be necessary in many cases. In those cases, you have to do it manually or via scripts. We provide the ipsec auto --unroute command for these cases.

From ipsec_auto(8):

Normally, pluto establishes a route to the destination specified for a connection as part of the --up operation. However, the route and only the route can be established with the --route operation. Until and unless an actual connection is established, this discards any packets sent there, which may be preferable to having them sent elsewhere based on a more general route (e.g., a default route).
Normally, pluto's route to a destination remains in place when a --down operation is used to take the connection down (or if connection setup, or later automatic rekeying, fails). This permits establishing a new connection (perhaps using a different specification; the route is altered as necessary) without having a ``window'' in which packets might go elsewhere based on a more general route. Such a route can be removed using the --unroute operation (and is implicitly removed by --delete).

See also this mailing list message.

The firewall ate my packets!

If firewalls filter out:

then IPsec cannot work. The first thing to check if packets seem to be vanishing is the firewall rules on the two gateway machines and any other machines along the path that you have access to.

For details, see our document on firewalls .

Some advice from technical lead Henry Spencer on diagnosing such problems:

> > Packets vanishing between the hardware interface and the ipsecN interface
> > is usually the result of firewalls not being configured to let them in...
> 
> Thanks for the suggestion. If only it were that simple! My ipchains startup
> script does take care of that, but just in case I manually inserted rules 
> accepting everything from london on dublin. No difference.

The other thing to check is whether the "RX packets dropped" count on the
ipsecN interface (run "ifconfig ipsecN", for N=1 or whatever, to see the
counts) is rising.  If so, then there's some sort of configuration mismatch
between the two ends, and IPsec itself is rejecting them.  If none of the
ipsecN counts is rising, then the packets are never reaching the IPsec
machinery, and the problem is almost certainly in firewalls etc.

Dropped connections

Networks being what they are, IPsec connections can be broken for any number of reasons, ranging from hardware failures to various software problems such as the path MTU problems discussed elsewhere in the FAQ. Fortunately, various diagnostic tools exist that help you sort out many of the possible problems.

There is one situation, however, where FreeS/WAN (using default settings) may destroy a connection for no readily apparent reason. This occurs when things are misconfigured so that two tunnels from the same gateway expect the same subnet on the far end.

In this situation, the first tunnel comes up fine and works until the second is established. At that point, because of the way we track connections internally, the first tunnel ceases to exist as far as this gateway is concerned. Of course the far end does not know that, and a storm of error messages appears on both systems as it tries to use the tunnel.

If the far end gives up, goes back to square one and negotiates a new tunnel, then that wipes out the second tunnel and ...

The solution is simple. Do not build multiple conn descriptions with the same remote subnet.

This is actually intended to be a feature, rather than a bug. Consider the situation where a single remote system goes down, then comes back up and reconnects to the gateway. It is useful to have the gateway tear down the old tunnel and recover resources when the reconnection is made. It recognises that situation by checking the remote subnet for each tunnel it builds and discarding duplicates. This works fine as long as you don't configure multiple tunnels with the same remote subnet.

If this behaviour is inconvenient for you, you can disable it by setting uniqueids=no in ipsec.conf(5).

Disappearing %defaultroute

When an underlying connection (eg. ppp) goes down, FreeS/WAN will not recover properly without a little help. Here are the symptoms that FreeS/WAN user Michael Carmody noticed:

> After about 24 hours the freeswan connection takes over the default route.
> 
> i.e instead of deafult gateway pointing to the router via eth0, it becomes a 
> pointer to the router via ipsec0.
 
> All internet access is then lost as all replies (and not just the link I 
> wanted) are routed out ipsec0 and the router doesn't respond to the ipsec 
> traffic.

If you're using a FreeS/WAN 2.x/KLIPS system, simply re-attach the IPsec virtual interface with ipsec tnconfig command such as:

    ipsec tnconfig --attach --virtual ipsec0 --physical ppp0

In your command, name the physical and virtual interfaces as they appear paired on your system during regular uptime. For a system with several physical/virtual interface pairs on flaky links, you'll need more than one such command. If you're using FreeS/WAN 1.x, you must restart FreeS/WAN, which is more time consuming.

Here is a script which can help to automate the process of FreeS/WAN restart at need. It could easily be adapted to use tnconfig instead.

TCPdump on the gateway shows strange things

As another user pointed out, keeping the connect

Attempting to look at IPsec packets by running monitoring tools on the IPsec gateway machine can produce silly results. That machine is mangling the packets for IPsec, and possibly for firewall or NAT purposes as well. If the internals of the machine's IP stack are not what the monitoring tool expects, then the tool can misinterpret them and produce nonsense output.

See our testing document for more detail.

Traceroute does not show anything between the gateways

As far as traceroute can see, the two gateways are one hop apart; the data packet goes directly from one to the other through the tunnel. Of course the outer packets that implement the tunnel pass through whatever lies between the gateways, but those packets are built and dismantled by the gateways. Traceroute does not see them and cannot report anything about their path.

Here is a mailing list message with more detail.

Date: Mon, 14 May 2001
To: linux-ipsec@freeswan.org
From: "John S. Denker" <jsd@research.att.com<
Subject: Re: traceroute: one virtual hop

At 02:20 PM 5/14/01 -0400, Claudia Schmeing wrote:
>
>> > A bonus question: traceroute in subnet to subnet enviroment looks like:
>> > 
>> > traceroute to andris.dmz (172.20.24.10), 30 hops max, 38 byte packets
>> > 1  drama (172.20.1.1)  0.716 ms  0.942 ms  0.434 ms
>> > 2  * * *
>> > 3  andris.dmz (172.20.24.10)  73.576 ms  78.858 ms  79.434 ms
>> > 
>> > Why aren't there the other hosts which take part in the delivery during 
>    * * * ?
>
>If there is an ipsec tunnel between GateA and Gate B, this tunnel forms a 
>'virtual wire'.  When it is tunneled, the original packet becomes an inner 
>packet, and new ESP and/or AH headers are added to create an outer packet 
>around it. You can see an example of how this is done for AH at 
>doc/ipsec.html#AH . For ESP it is similar.
>
>Think about the packet's path from the inner packet's perspective.
>It leaves the subnet, goes into the tunnel, and re-emerges in the second
>subnet. This perspective is also the only one available to the
>'traceroute' command when the IPSec tunnel is up.

Claudia got this exactly right.  Let me just expand on a couple of points:

*) GateB is exactly one (virtual) hop away from GateA.  This is how it
would be if there were a physically private wire from A to B.  The
virtually private connection should work the same, and it does.

*) While the information is in transit from GateA to GateB, the hop count
of the outer header (the "envelope") is being decremented.  The hop count
of the inner header (the "contents" of the envelope) is not decremented and
should not be decremented.  The hop count of the outer header is not
derived from and should not be derived from the hop count of the inner header.

Indeed, even if the packets did time out in transit along the tunnel, there
would be no way for traceroute to find out what happened.  Just as
information cannot leak _out_ of the tunnel to the outside, information
cannot leak _into_ the tunnel from outside, and this includes ICMP messages
from routers along the path.

There are some cases where one might wish for information about what is
happening at the IP layer (below the tunnel layer) -- but the protocol
makes no provision for this.  This raises all sorts of conceptual issues.
AFAIK nobody has ever cared enough to really figure out what _should_
happen, let alone implement it and standardize it.

*) I consider the "* * *" to be a slight bug.  One might wish for it to be
replaced by "GateB GateB GateB".  It has to do with treating host-to-subnet
traffic different from subnet-to-subnet traffic (and other gory details).
I fervently hope KLIPS2 will make this problem go away.

*) If you want to ask questions about the link from GateA to GateB at the
IP level (below the tunnel level), you have to ssh to GateA and launch a
traceroute from there.

Testing in stages

It is often useful in debugging to test things one at a time:

FreeS/WAN releases are tested for all of these, so you can be reasonably certain they can do them all. Of course, that does not mean they will on the first try, especially if you have some unusual configuration.

The rest of this section gives information on diagnosing the problem when each of the above steps fails.

Manually keyed connections don't work

Suspect one of:

One manual connection works, but second one fails

This is a fairly common problem when attempting to configure multiple manually keyed connections from a single gateway.

Each connection must be identified by a unique SPI value. For automatic connections, these values are assigned automatically. For manual connections, you must set them with spi= statements in ipsec.conf(5).

Each manual connection must have a unique SPI value in the range 0x100 to 0x999. Two or more with the same value will fail. For details, see our doc section Using manual keying in production and the man page ipsec.conf(5).

Manual connections work, but automatic keying doesn't

The most common reason for this behaviour is a firewall dropping the UDP port 500 packets used in key negotiation.

Other possibilities:

IPsec works, but connections using compression fail

When we first added compression, we saw some problems:

We have not seen either problem in some time (at least six months as I write in March 2002), but if you have some unusual configuration then you may see them.

Small packets work, but large transfers fail

If tests with ping(1) and a small packet size succeed, but tests or transfers with larger packet sizes fail, suspect problems with packet fragmentation and perhaps path MTU discovery.

Our troubleshooting document covers these problems. Information on the underlying mechanism is in our background document.

Subnet-to-subnet works, but tests from the gateways don't

This is described under I cannot ping... above.

Compilation problems

gmp.h: No such file or directory

Pluto needs the GMP (GNU

Multi-Precision) library for the large integer calculations it uses in public key cryptography. This error message indicates a failure to find the library. You must install it before Pluto will compile.

The GMP library is included in most Linux distributions. Typically, there are two RPMs, libgmp and libgmp-devel, You need to install both, either from your distribution CDs or from your vendor's web site.

On Debian, a mailing list message reports that the command to give is apt-get install gmp2.

For more information and the latest version, see the GMP home page.

... virtual memory exhausted

We have had several reports of this message appearing, all on SPARC Linux. Here is a mailing message on a solution:

> ipsec_sha1.c: In function `SHA1Transform':
> ipsec_sha1.c:95: virtual memory exhausted

I'm seeing exactly the same problem on an Ultra with 256MB ram and 500
MB swap.  Except I am compiling version 1.5 and its Red Hat 6.2.

I can get around this by using -O instead of -O2 for the optimization
level.  So it is probably a bug in the optimizer on the sparc complier. 
I'll try and chase this down on the sparc lists.

Interpreting error messages

route-client (or host) exited with status 7

Here is a discussion of this error from FreeS/WAN "listress" (mailing list tech support person) Claudia Schmeing. The "FAQ on the network unreachable error" which she refers to is the next question below.

> I reached the point where the two boxes (both on dial-up connections, but
> treated as static IPs by getting the IP and editing ipsec.conf after the
> connection is established) to the point where they exchange some info, but I
> get an error like "route-client command exited with status 7 \n internal
> error".
> Where can I find a description of this error?

In general, if the FAQ doesn't cover it, you can search the mailing list 
archives - I like to use
http://www.sandelman.ottawa.on.ca/linux-ipsec/
but you can see doc/mail.html for different archive formats.


Your error comes from the _updown script, which performs some
routing and firewall functions to help Linux FreeS/WAN. More info
is available at doc/firewall.html and man ipsec.conf. Its routing
is integral to the health of Linux FreeS/WAN; it also provides facility
to insert custom firewall rules to be executed when you create or destroy
a connection.

Yours is, of course, a routing error. You can be fairly sure the routing 
machinery is saying "network is unreachable". There's a FAQ on the 
"network is unreachable" error, but more information is available now; read on.

If your _updown script is recent (for example if it shipped with 
Linux FreeS/WAN 1.91), you will see another debugging line in your logs 
that looks something like this:

> output: /usr/lib/ipsec/_updown: `route add -net 128.174.253.83 
> netmask 255.255.255.255 dev ipsec0 gw 66.92.93.161' failed

This is, of course, the system route command that exited with status 7, 
(ie. failed). Man route for details. Seeing the command typed out yields 
more information. If your _updown script is older, you may wish to update 
it to show the command explicitly.

Three parameters fed to the route command: net, netmask and gw [gateway] 
are derived from things you've put in ipsec.conf.

Net and netmask are derived from the peer's IP and mask. In more detail:

You may see a routing error when routing to a client (ie. subnet), or 
to a host (IPSec gateway or freestanding host; a box that does IPSec for
itself). In _updown, the "route-client" section  is responsible to set up 
the route for IPSec'd (usually, read 'tunneled') packets headed to a 
peer subnet. Similarly, route-host routes IPSec'd packets to a peer host
or IPSec gateway.

When routing to a 'client', net and netmask are ipsec.conf's left- or 
rightsubnet (whichever is not local). Similarly, when routing to a 
'host' the net is left or right. Host netmask is always /32, indicating a 
single machine.

Gw is nexthop's value. Again, the value in question is left- or rightnexthop,
whichever is local. Where left/right or left-/rightnexthop has the special 
value %defaultroute (described in man ipsec.conf), gw will automagically get
the value of the next hop on the default route.

Q: "What's a nexthop and why do I need one?"

A: 'nexthop' is a routing kluge; its value is the next hop away
   from the machine that's doing IPSec, and toward your IPSec peer. 
   You need it to get the processed packets out of the local system and 
   onto the wire. While we often route other packets through the machine 
   that's now doing IPSec, and are done with it, this does not suffice here. 
   After packets are processed with IPSec, this machine needs to know where 
   they go next. Of course using the 'IPSec gateway' as their routing gateway 
   would cause an infinite loop! [To visualize this, see the packet flow 
   diagram at doc/firewall.html.] To avoid this, we route packets through 
   the next hop down their projected path.

Now that you know the background, consider:
1. Did you test routing between the gateways in the absence of Linux
   FreeS/WAN, as recommended? You need to ensure the two machines that
   will be running Linux FreeS/WAN can route to one another before trying to 
   make a secure connection.
2. Is there anything obviously wrong with the sense of your route command?

Normally, this problem is caused by an incorrect local nexthop parameter.
Check out the use of %defaultroute, described in man ipsec.conf. This is
a simple way to set nexthop for most people. To figure nexthop out by hand,
traceroute in-the-clear to your IPSec peer. Nexthop is the traceroute's 
first hop after your IPSec gateway.

SIOCADDRT:Network is unreachable

This message is not from FreeS/WAN, but from the Linux IP stack itself. That stack is seeing packets it has no route for, either because your routing was broken before FreeS/WAN started or because FreeS/WAN's changes broke it.

Here is a message from Claudia suggesting ways to diagnose and fix such problems:

You write,
> I have correctly installed freeswan-1.8 on RH7.0 kernel 2.2.17, but when 
> I setup a VPN connection with the other machine(RH5.2 Kernel 2.0.36 
> freeswan-1.0, it works well.) it told me that 
> "SIOCADDRT:Network is unreachable"!  But the network connection is no 
> problem.

Often this error is the result of a misconfiguration. 

Be sure that you can route successfully in the absence of Linux
FreeS/WAN. (You say this is no problem, so proceed to the next step.)

Use a custom copy of the default updownscript. Do not change the route 
commands, but add a diagnostic message revealing the exact text of the 
route command. Is there a problem with the sense of the route command
that you can see? If so, then re-examine those ipsec.conf settings
that are being sent to the route command. 

You may wish to use the ipsec auto --route and --unroute commands to 
troubleshoot the problem. See man ipsec_auto for details.

Since the above message was written, we have modified the updown script to provide a better diagnostic for this problem. Check /var/log/messages.

See also the FAQ question route-client (or host) exited with status 7.

ipsec_setup: modprobe: Can't locate module ipsec

ipsec_setup: Fatal error, kernel appears to lack KLIPS

These messages indicate an installation failure. The kernel you are running does not contain the KLIPS (kernel IPsec) code.

Note that the "modprobe: Can't locate module ipsec" message appears even if you are not using modules. If there is no KLIPS in your kernel, FreeS/WAN tries to load it as a module. If that fails, you get this message.

Commands you can quickly try are:

uname -a
to get details, including compilation date and time, of the currently running kernel
ls /
ls /boot
to ensure a new kernel is where it should be. If kernel compilation puts it in / but lilo wants it in /boot , then you should uncomment the INSTALL_PATH=/boot line in the kernel Makefile.
more /etc/lilo.conf
to see that lilo has correct information
lilo
to ensure that information in /etc/lilo.conf has been transferred to the boot sector

If those don't find the problem, you have to go back and check through the install procedure to see what was missed.

Here is one of Claudia's messages on the topic:

> I tried to install freeswan 1.8 on my mandrake 7.2 test box. ...

> It does show version and some output for whack.

Yes, because the Pluto (daemon) part of ipsec is installed correctly, but
as we see below the kernel portion is not.

> However, I get the following from /var/log/messages:
> 
> Mar 11 22:11:55 pavillion ipsec_setup: Starting FreeS/WAN IPsec 1.8...
> Mar 11 22:12:02 pavillion ipsec_setup: modprobe: Can't locate module ipsec
> Mar 11 22:12:02 pavillion ipsec_setup: Fatal error, kernel appears to lack
> KLIPS.

This is your problem. You have not successfully installed a kernel with
IPSec machinery in it. 

Did you build Linux FreeS/WAN as a module? If so, you need to ensure that 
your new module has been installed in the directory where your kernel 
loader normally finds your modules. If not, you need to ensure
that the new IPSec-enabled kernel is being loaded correctly.

See also doc/install.html, and INSTALL in the distro.

ipsec_setup: ... failure to fetch key for ... from DNS

Quoting Henry:

Note that by default, FreeS/WAN is now set up to
     (a) authenticate with RSA keys, and
     (b) fetch the public key of the far end from DNS.
Explicit attention to  ipsec.conf will be needed if you want
to do something different.

and Claudia, responding to the same user:

You write,

>       My current setup in ipsec.conf is leftrsasigkey=%dns I have 
> commented this and authby=rsasig out. I am able to get ipsec running, 
> but what I find is that the documentation only specifies for %dns are 
> there any other values that can be placed in this variable other than 
> %dns and the key? I am also assuming that this is where I would place 
> my public key for the left and right side as well is this correct?

Valid values for authby= are rsasig and secret, which entail authentication
by RSA signature or by shared secret, respectively. Because you have 
commented authby=rsasig out, you are using the default value of authby=secret. 

When using RSA signatures, there are two ways to get the public key for the
IPSec peer: either copy it directly into *rsasigkey= in ipsec.conf, or
fetch it from dns. The magic value %dns for *rsasigkey parameters says to 
try to fetch the peer's key from dns.

For any parameters, you may find their significance and special values in
man ipsec.conf. If you are setting up keys or secrets, be sure also to
reference man ipsec.secrets.

ipsec_setup: ... interfaces ... and ... share address ...

This is a fatal error. FreeS/WAN cannot cope with two or more interfaces using the same IP address. You must re-configure to avoid this.

A mailing list message on the topic from Pluto developer Hugh Redelmeier:

| I'm trying to get freeswan working between two machine where one has a ppp
| interface.
| I've already suceeded with  two machines with ethernet ports but  the ppp
| interface is causing me problems.
|  basically when I run ipsec start  i get
| ipsec_setup: Starting FreeS/WAN IPsec 1.7...
| ipsec_setup: 003 IP interfaces ppp1 and ppp0 share address 192.168.0.10!
| ipsec_setup: 003 IP interfaces ppp1 and ppp2 share address 192.168.0.10!
| ipsec_setup: 003 IP interfaces ppp0 and ppp2 share address 192.168.0.10!
| ipsec_setup: 003 no public interfaces found
|
| followed by lots of cannot work out interface for connection messages
|
| now I can specify the interface in ipsec.conf to be ppp0 , but this does
| not affect the above behaviour. A quick look in server.c indicates that the
| interfaces value  is not used but some sort of raw detect happens.
|
| I guess I could prevent the formation of the extra ppp interfaces or
| allocate them different ip but I'd  rather not. if at all possible. Any
| suggestions please.

Pluto won't touch an interface that shares an IP address with another.
This will eventually change, but it probably won't happen soon.

For now, you will have to give the ppp1 and ppp2 different addresses.

ipsec_setup: Cannot adjust kernel flags

A mailing list message form technical lead Henry Spencer:

> When FreeS/WAN IPsec 1.7 is starting on my 2.0.38 Linux kernel the following
> error message is generated:
> ipsec_setup: Cannot adjust kernel flags, no /proc/sys/net/ipsec directory!
> What is supposed to create this directory and how can I fix this problem?

I think that directory is a 2.2ism, although I'm not certain (I don't have
a 2.0.xx system handy any more for testing).  Without it, some of the
ipsec.conf config-setup flags won't work, but otherwise things should
function. 

You also need to enable the /proc filesystem in your kernel configuration for these operations to work.

Message numbers (MI3, QR1, et cetera) in Pluto messages

Pluto messages often indicate where Pluto is in the IKE protocols. The letters indicate Main mode or Q uick mode and Initiator or Responder. The numerals are message sequence numbers. For more detail, see our IPsec section.

Connection names in Pluto error messages

From Pluto programmer Hugh Redelmeier:

| Jan 17 16:21:10 remus Pluto[13631]: "jumble" #1: responding to Main Mode from Road Warrior 130.205.82.46
| Jan 17 16:21:11 remus Pluto[13631]: "jumble" #1: no suitable connection for peer @banshee.wittsend.com
| 
|     The connection "jumble" has nothing to do with the incoming
| connection requests, which were meant for the connection "banshee".

You are right.  The message tells you which Connection Pluto is
currently using, which need not be the right one.  It need not be the
right one now for the negotiation to eventually succeed!  This is
described in ipsec_pluto(8) in the section "Road Warrior Support".

There are two times when Pluto will consider switching Connections for
a state object.  Both are in response to receiving ID payloads (one in
Phase 1 / Main Mode and one in Phase 2 / Quick Mode).  The second is
not unique to Road Warriors.  In fact, neither is the first any more
(two connections for the same pair of hosts could differ in Phase 1 ID
payload; probably nobody else has tried this).

Pluto: ... can't orient connection

Older versions of FreeS/WAN used this message. The same error now gives the "we have no ipsecN ..." error described just below.

... we have no ipsecN interface for either end of this connection

Your tunnel has no IP address which matches the IP address of any of the available IPsec interfaces. Either you've misconfigured the connection, or you need to define an appropriate IPsec interface connection. interfaces=%defaultroute works in many cases.

A longer story: Pluto needs to know whether it is running on the machine which the connection description calls left or on right. It figures that out by:

Normally a match is found. Then Pluto knows where it is and can set up other things (for example, if it is left) using parameters such as leftsubnet and leftnexthop, and sending its outgoing packets to right.

If no match is found, it emits the above error message.

Pluto: ... no connection is known

This error message occurs when a remote system attempts to negotiate a connection and Pluto does not have a connection description that matches what the remote system has requested. The most common cause is a configuration error on one end or the other.

Parameters involved in this match are left, right , leftsubnet and rightsubnet.

The match must be exact. For example, if your left subnet is a.b.c.0/24 then neither a single machine in that net nor a smaller subnet such as a.b.c.64/26 will be considered a match.

The message can also occur when an appropriate description exists but Pluto has not loaded it. Use an auto=add statement in the connection description, or an ipsec auto --add <conn_name> command, to correct this.

An explanation from the Pluto developer:

| Jul 12 15:00:22 sohar58 Pluto[574]: "corp_road" #2: cannot respond to IPsec
| SA request because no connection is known for
| 216.112.83.112/32===216.112.83.112...216.67.25.118

This is the first message from the Pluto log showing a problem.  It
means that PGPnet is trying to negotiate a set of SAs with this
topology:

216.112.83.112/32===216.112.83.112...216.67.25.118
^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^   ^^^^^^^^^^^^^
client on our side  our host         PGPnet host, no client

None of the conns you showed look like this.

Use
        ipsec auto --status
to see a snapshot of what connections are in pluto, what
negotiations are going on, and what SAs are established.

The leftsubnet= (client) in your conn is 216.112.83.64/26.  It must
exactly match what pluto is looking for, and it does not.

Pluto: ... no suitable connection ...

This is similar to the no connection known error, but occurs at a different point in Pluto processing.

Here is one of Claudia's messages explaining the problem:

You write,

> What could be the reason of the following error? 
> "no suitable connection for peer '@xforce'"

When a connection is initiated by the peer, Pluto must choose which entry in 
the conf file best matches the incoming connection. A preliminary choice is 
made on the basis of source and destination IPs, since that information is 
available at that time. 

A payload containing an ID arrives later in the negotiation. Based on this
id and the *id= parameters, Pluto refines its conn selection. ...

The message "no suitable connection" indicates that in this refining step,
Pluto does not find a connection that matches that ID.

Please see "Selecting a connection when responding" in man ipsec_pluto for
more details.

See also Connection names in Pluto error messages.

Pluto: ... no connection has been authorized

Here is one of Claudia's messages discussing this problem:

You write,

>  May 22 10:46:31 debian Pluto[25834]: packet from x.y.z.p:10014: 
>  initial Main Mode message from x.y.z.p:10014 
                            but no connection has been authorized

This error occurs early in the connection negotiation process,
at the first step of IKE negotiation (Main Mode), which is itself the 
first of two negotiation phases involved in creating an IPSec connection.

Here, Linux FreeS/WAN receives a packet from a potential peer, which 
requests that they begin discussing a connection.

The "no connection has been authorized" means that there is no connection 
description in Linux FreeS/WAN's internal database that can be used to 
link your ipsec interface with that peer.

"But of course I configured that connection!" 

It may be that the appropriate connection description exists in ipsec.conf 
but has not been added to the database with ipsec auto --add myconn or the 
auto=add method. Or, the connection description may be misconfigured.

The only parameters that are relevant in this decision are left= and right= .
Local and remote ports are also taken into account -- we see that the port 
is printed in the message above -- but there is no way to control these
in ipsec.conf.


Failure at "no connection has been authorized" is similar to the
"no connection is known for..." error in the FAQ, and the "no suitable
connection" error described in the snapshot's FAQ. In all three cases,
Linux FreeS/WAN is trying to match parameters received in the
negotiation with the connection description in the local config file.

As it receives more information, its matches take more parameters into 
account, and become more precise:  first the pair of potential peers,
then the peer IDs, then the endpoints (including any subnets).

The "no suitable connection for peer *" occurs toward the end of IKE 
(Main Mode) negotiation, when the IDs are matched.

"no connection is known for a/b===c...d" is seen at the beginning of IPSec 
(Quick Mode, phase 2) negotiation, when the connections are matched using
left, right, and any information about the subnets.

Pluto: ... OAKLEY_DES_CBC is not supported.

This message occurs when the other system attempts to negotiate a connection using single DES, which we do not support because it is insecure.

Our interoperation document has suggestions for how to deal with systems that attempt to use single DES.

Pluto: ... no acceptable transform

This message means that the other gateway has made a proposal for connection parameters, but nothing they proposed is acceptable to Pluto. Possible causes include:

A more detailed explanation, from Pluto programmer Hugh Redelmeier:

Background:

When one IKE system (for example, Pluto) is negotiating with another
to create an SA, the Initiator proposes a bunch of choices and the
Responder replies with one that it has selected.

The structure of the choices is fairly complicated.  An SA payload
contains a list of lists of "Proposals".  The outer list is a set of
choices: the selection must be from one element of this list.

Each of these elements is a list of Proposals.  A selection must be
made from each of the elements of the inner list.  In other words,
*all* of them apply (that is how, for example, both AH and ESP can
apply at once).

Within each of these Proposals is a list of Transforms.  For each
Proposal selected, one Transform must be selected (in other words,
each Proposal provides a choice of Transforms).

Each Transform is made up of a list of Attributes describing, well,
attributes.  Such as lifetime of the SA.  Such as algorithm to be
used.  All the Attributes apply to a Transform.

You will have noticed a pattern here: layers alternate between being
disjunctions ("or") and conjunctions ("and").

For Phase 1 / Main Mode (negotiating an ISAKMP SA), this structure is
cut back.  There must be exactly one Proposal.  So this degenerates to
a list of Transforms, one of which must be chosen.

In your case, no proposal was considered acceptable to Pluto (the
Responder).  So negotiation ceased.  Pluto logs the reason it rejects
each Transform.  So look back in the log to see what is going wrong.

rsasigkey dumps core

A comment on this error from Henry:
On Fri, 29 Jun 2001, Rodrigo Gruppelli wrote:
> ...Well, it seem that there's
> another problem with it. When I try to generate a pair of RSA keys,
> rsasigkey cores dump...

*That* is a neon sign flashing "GMP LIBRARY IS BROKEN".  Rsasigkey calls
GMP a lot, and our own library a little bit, and that's very nearly all it
does.  Barring bugs in its code or our library -- which have happened, but
not very often -- a problem in rsasigkey is a problem in GMP.

See the next question for how to deal with GMP errors.

!Pluto failure!: ... exited with ... signal 4

Pluto has died. Signal 4 is SIGILL, illegal instruction.

The most likely cause is that your GMP (GNU multi-precision) library is compiled for a different processor than what you are running on. Pluto uses that library for its public key calculations.

Try getting the GMP sources and recompile for your processor type. Most Linux distributions will include this source, or you can download it from the GMP home page.

ECONNREFUSED error message

From John Denker, on the mailing list:

1)  The log message
  some IKE message we sent has been rejected with 
  ECONNREFUSED (kernel supplied no details)
is much more suitable than the previous version.  Thanks.

2) Minor suggestion for further improvement: it might be worth mentioning
that the command
  tcpdump -i eth1 icmp[0] != 8 and icmp[0] != 0
is useful for tracking down the details in question.  We shouldn't expect
all IPsec users to figure that out on their own.  The log message might
even provide a hint as to where to look in the docs.

Reply From Pluto developer Hugh Redelmeier

Good idea.

I've added a bit pluto(8)'s BUGS section along these lines.
I didn't have the heart to lengthen this message.

klips_debug: ... no eroute!

This message means KLIPS has received a packet for which no IPsec tunnel has been defined.

Here is a more detailed duscussion from the team's tech support person Claudia Schmeing, responding to a query on the mailing list:

> Why ipsec reports no eroute! ???? IP Masq... is disabled.

In general, more information is required so that people on the list may
give you informed input. See doc/prob.report.

The document she refers to has since been replaced by a section of the troubleshooting document.

However, I can make some general comments on this type of error.

This error usually looks something like this (clipped from an archived
message):

> ttl:64 proto:1 chk:45459 saddr:192.168.1.2 daddr:192.168.100.1
> ... klips_debug:ipsec_findroute: 192.168.1.2->192.168.100.1
> ... klips_debug:rj_match: * See if we match exactly as a host destination
> ... klips_debug:rj_match: ** try to match a leaf, t=0xc1a260b0
> ... klips_debug:rj_match: *** start searching up the tree, t=0xc1a260b0
> ... klips_debug:rj_match: **** t=0xc1a260c8
> ... klips_debug:rj_match: **** t=0xc1fe5960
> ... klips_debug:rj_match: ***** not found.
> ... klips_debug:ipsec_tunnel_start_xmit: Original head/tailroom: 2, 28
> ... klips_debug:ipsec_tunnel_start_xmit: no eroute!: ts=47.3030, dropping.


What does this mean?
- --------------------

"eroute" stands for "extended route", and is a special type of route 
internal to Linux FreeS/WAN. For more information about this type of route, 
see the section of man ipsec_auto on ipsec auto --route.

"no eroute!" here means, roughly, that Linux FreeS/WAN cannot find an 
appropriate tunnel that should have delivered this packet. Linux 
FreeS/WAN therefore drops the packet, with the message "no eroute! ...
dropping", on the assumption that this packet is not a legitimate 
transmission through a properly constructed tunnel.


How does this situation come about?
- -----------------------------------

Linux FreeS/WAN has a number of connection descriptions defined in 
ipsec.conf. These must be successfully brought "up" to form actual tunnels.
(see doc/setup.html's step 15, man ipsec.conf and man ipsec_auto 
for details).

Such connections are often specific to the endpoints' IPs. However, in 
some cases they may be more general, for example in the case of 
Road Warriors where left or right is the special value %any.

When Linux FreeS/WAN receives a packet, it verifies that the packet has
come through a legitimate channel, by checking that there is an
appropriate tunnel through which this packet might legitimately have
arrived. This is the process we see above.

First, it checks for an eroute that exactly matches the packet. In the 
example above, we see it checking for a route that begins at 192.168.1.2
and ends at 192.168.100.1. This search favours the most specific match that
would apply to the route between these IPs. So, if there is a connection 
description exactly matching these IPs, the search will end there. If not, 
the code will search for a more general description matching the IPs.
If there is no match, either specific or general, the packet will be
dropped, as we see, above.

Unless you are working with Road Warriors, only the first, specific part 
of the matching process is likely to be relevant to you.


"But I defined the tunnel, and it came up, why do I have this error?"
- ---------------------------------------------------------------------

One of the most common causes of this error is failure to specify enough
connection descriptions to cover all needed tunnels between any two 
gateways and their respective subnets. As you have noticed, troubleshooting
this error may be complicated by the use of IP Masq. However, this error is
not limited to cases where IP Masq is used. 

See doc/configuration.html#multitunnel for a detailed example of the 
solution to this type of problem.

The documentation section she refers to is now here.

... trouble writing to /dev/ipsec ... SA already in use

This error message occurs when two manual connections are set up with the same SPI value.

See the FAQ for One manual connection works, but second one fails.

... ignoring ... payload

This message is harmless. The IKE protocol provides for a number of optional messages types:

An implementation is never required to send these, but they are allowed to. The receiver is not required to do anything with them. FreeS/WAN ignores them, but notifies you via the logs.

For the "ignoring delete SA Payload" message, see also our discussion of cleaning up dead tunnels.

unknown parameter name "rightcert"

This message can appear when you've upgraded an X.509-enabled Linux FreeS/WAN with a vanilla Linux FreeS/WAN. To use your X.509 configs you will need to overwrite the new install with Super FreeS/WAN, or add the X.509 patch by hand.

Why don't you restrict the mailing lists to reduce spam?

As a matter of policy, some of our mailing lists need to be open to non-subscribers. Project management feel strongly that maintaining this openness is more important than blocking spam.

This has been discussed several times at some length on the list. See the list archives. Bringing the topic up again is unlikely to be useful. Please don't. Or at the very least, please don't without reading the archives and being certain that whatever you are about to suggest has not yet been discussed.

Project technical lead Henry Spencer summarised one discussion:

For the third and last time: this list *will* *not* do address-based filtering. This is a policy decision, not an implementation problem. The decision is final, and is not open to discussion. This needs to be communicated better to people, and steps are being taken to do that.

Adding this FAQ section is one of the steps he refers to.

You have various options other than just putting up with the spam, filtering it yourself, or unsubscribing:

A number of tools are available to filter mail.

If you use your ISP's mail server rather than running your own, consider suggesting to the ISP that they tag suspected spam as this ISP does. They could just refuse mail from dubious sources, but that is tricky and runs some risk of losing valuable mail or senselessly annoying senders and their admins. However, they can safely tag and deliver dubious mail. The tags can greatly assist your filtering.

For information on tracking down spammers, see these HowTos, or the Sputum site. Sputum have a Linux anti-spam screensaver available for download.

Here is a more detailed message from Henry:

On Mon, 15 Jan 2001, Jay Vaughan wrote:
> I know I'm flogging a dead horse here, but I'm curious as to the reasons for
> an aversion for a subscriber-only mailing list?

Once again:  for legal reasons, it is important that discussions of these
things be held in a public place -- the list -- and we do not want to
force people to subscribe to the list just to ask one question, because
that may be more than merely inconvenient for them.  There are also real
difficulties with people who are temporarily forced to use alternate
addresses; that is precisely the time when they may be most in need of
help, yet a subscribers-only policy shuts them out.

These issues do not apply to most mailing lists, but for a list that is
(necessarily) the primary user support route for a crypto package, they
are very important.  This is *not* an ordinary mailing list; it has to
function under awkward constraints that make various simplistic solutions
inapplicable or undesirable. 

> We're *ALL* sick of hearing about list management problems, not just you
> old-timers, so why don't you DO SOMETHING EFFECTIVE ABOUT IT...

Because it's a lot harder than it looks, and many existing "solutions"
have problems when examined closely.

> A suggestion for you, based on 10 years of experience with management of my
> own mailing lists would be to use mailman, which includes pretty much every
> feature under the sun that you guys need and want, plus some.  The URL for
> mailman...

I assure you, we're aware of mailman.  Along with a whole bunch of others,
including some you almost certainly have never heard of (I hadn't!).

> As for the argument that the list shouldn't be configured to enforce
> subscription - I contend that it *SHOULD* AT LEAST require manual address
> verification in order for posts to be redirected.

You do realize, I hope, that interposing such a manual step might cause
your government to decide that this is not truly a public forum, and thus
you could go to jail if you don't get approval from them before mailing to
it?  If you think this sounds irrational, your government is noted for
making irrational decisions in this area; we can't assume that they will
suddenly start being sensible.  See above about awkward constraints.  You
may be willing to take the risk, but we can't, in good conscience, insist
that all users with problems do so. 

                                                          Henry Spencer
                                                       henry@spsystems.net

and a message on the topic from project leader John Gilmore:

Subject: Re: The linux-ipsec list's topic
   Date: Sat, 30 Dec 2000
   From: John Gilmore <gnu@toad.com>

I'll post this single message, once only, in this discussion, and then
not burden the list with any further off-topic messages.  I encourage
everyone on the list to restrain themself from posting ANY off-topic
messages to the linux-ipsec list.

The topic of the linux-ipsec mailing list is the FreeS/WAN software.

I frequently see "discussions about spam on a list" overwhelm the
volume of "actual spam" on a list. BOTH kinds of messages are
off-topic messages.  Twenty anti-spam messages take just as long to
detect and discard as twenty spam messages.

The Linux-ipsec list encourages on-topic messages from people who have
not joined the list itself.  We will not censor messages to the list
based on where they originate, or what return address they contain.
In other words, non-subscribers ARE allowed to post, and this will not
change.  My own valid contributions have been rejected out-of-hand by
too many other mailing lists for me to want to impose that censorship
on anybody else's contributions.  And every day I see the damage that
anti-spam zeal is causing in many other ways; that zeal is far more
damaging to the culture of the Internet than the nuisance of spam.

In general, it is the responsibility of recipients to filter,
prioritize, or otherwise manage the handling of email that comes to
them.  It is not the responsibility of the rest of the Internet
community to refrain from sending messages to recipients that they
might not want to see.  If your software infrastructure for managing
your incoming email is insufficient, then improve it.  If you think
the signal-to-noise ratio on linux-ipsec is too poor, then please
unsubscribe.  But don't further increase the noise by posting to the
linux-ipsec list about those topics.

        John Gilmore
        founder & sponsor, FreeS/WAN project

FreeS/WAN manual pages

The various components of Linux FreeS/WAN are of course documented in standard Unix manual pages, accessible via the man(1) command.

Links here take you to an HTML version of the man pages.

Files

ipsec.conf(5)
IPsec configuration and connections
ipsec.secrets(5)
secrets for IKE authentication, either pre-shared keys or RSA private keys

These files are also discussed in the configuration section.

Commands

Many users will never give most of the FreeS/WAN commands directly. Configure the files listed above correctly and everything should be automatic.

The exceptions are commands for mainpulating the RSA keys used in Pluto authentication:

ipsec_rsasigkey(8)
generate keys
ipsec_newhostkey(8)
generate keys in a convenient format
ipsec_showhostkey(8)
extract RSA keys from ipsec.secrets(5) (or optionally, another file) and format them for insertion in ipsec.conf(5) or in DNS records

Note that:

The following commands are fairly likely to be used, if only for testing and status checks:

ipsec(8)
invoke IPsec utilities
ipsec_setup(8)
control IPsec subsystem
ipsec_auto(8)
control automatically-keyed IPsec connections
ipsec_manual(8)
take manually-keyed IPsec connections up and down
ipsec_ranbits(8)
generate random bits in ASCII form
ipsec_look(8)
show minimal debugging information
ipsec_barf(8)
spew out collected IPsec debugging information

The lower-level utilities listed below are normally invoked via scripts listed above, but they can also be used directly when required.

ipsec_eroute(8)
manipulate IPsec extended routing tables
ipsec_klipsdebug(8)
set Klips (kernel IPsec support) debug features and level
ipsec_pluto(8)
IPsec IKE keying daemon
ipsec_spi(8)
manage IPsec Security Associations
ipsec_spigrp(8)
group/ungroup IPsec Security Associations
ipsec_tncfg(8)
associate IPsec virtual interface with real interface
ipsec_whack(8)
control interface for IPsec keying daemon

Library routines

ipsec_atoaddr(3)
ipsec_addrtoa(3)
convert Internet addresses to and from ASCII
ipsec_atosubnet(3)
ipsec_subnettoa(3)
convert subnet/mask ASCII form to and from addresses
ipsec_atoasr(3)
convert ASCII to Internet address, subnet, or range
ipsec_rangetoa(3)
convert Internet address range to ASCII
ipsec_atodata(3)
ipsec_datatoa(3)
convert binary data from and to ASCII formats
ipsec_atosa(3)
ipsec_satoa(3)
convert IPsec Security Association IDs to and from ASCII
ipsec_atoul(3)
ipsec_ultoa(3)
convert unsigned-long numbers to and from ASCII
ipsec_goodmask(3)
is this Internet subnet mask a valid one?
ipsec_masktobits(3)
convert Internet subnet mask to bit count
ipsec_bitstomask(3)
convert bit count to Internet subnet mask
ipsec_optionsfrom(3)
read additional ``command-line'' options from file
ipsec_subnetof(3)
given Internet address and subnet mask, return subnet number
ipsec_hostof(3)
given Internet address and subnet mask, return host part
ipsec_broadcastof(3)
given Internet address and subnet mask, return broadcast address

FreeS/WAN and firewalls

FreeS/WAN, or other IPsec implementations, frequently run on gateway machines, the same machines running firewall or packet filtering code. This document discusses the relation between the two.

The firewall code in 2.4 and later kernels is called Netfilter. The user-space utility to manage a firewall is iptables(8). See the netfilter/iptables web site for details.

Filtering rules for IPsec packets

The basic constraint is that an IPsec gateway must have packet filters that allow IPsec packets, at least when talking to other IPsec gateways:

Your gateway and the other IPsec gateways it communicates with must be able to exchange these packets for IPsec to work. Firewall rules must allow UDP 500 and at least one of AH or ESP on the interface that communicates with the other gateway.

For nearly all FreeS/WAN applications, you must allow UDP port 500 and the ESP protocol.

There are two ways to set this up:

easier but less flexible
Just set up your firewall scripts at boot time to allow IPsec packets to and from your gateway. Let FreeS/WAN reject any bogus packets.
more work, giving you more precise control
Have the ipsec_pluto(8) daemon call scripts to adjust firewall rules dynamically as required. This is done by naming the scripts in the ipsec.conf(5) variables prepluto=, postpluto= , leftupdown= and rightupdown=.

Both methods are described in more detail below.

Firewall configuration at boot

It is possible to set up both firewalling and IPsec with appropriate scripts at boot and then not use leftupdown= and rightupdown=, or use them only for simple up and down operations.

Basically, the technique is

Since Pluto authenticates its partners during the negotiation, and KLIPS drops packets for which no tunnel has been negotiated, this may be all you need.

A simple set of rules

In simple cases, you need only a few rules, as in this example:

# allow IPsec
#
# IKE negotiations
iptables -I INPUT  -p udp --sport 500 --dport 500 -j ACCEPT
iptables -I OUTPUT -p udp --sport 500 --dport 500 -j ACCEPT
# ESP encryption and authentication
iptables -I INPUT  -p 50 -j ACCEPT
iptables -I OUTPUT -p 50 -j ACCEPT

This should be all you need to allow IPsec through lokkit, which ships with Red Hat 9, on its medium security setting. Once you've tweaked to your satisfaction, save your active rule set with:

service iptables save

Other rules

You can add additional rules, or modify existing ones, to work with IPsec and with your network and policies. We give a some examples in this section.

However, while it is certainly possible to create an elaborate set of rules yourself (please let us know via the mailing list if you do), it may be both easier and more secure to use a set which has already been published and tested.

The published rule sets we know of are described in the next section.

Adding additional rules

If necessary, you can add additional rules to:
reject IPsec packets that are not to or from known gateways
This possibility is discussed in more detail later
allow systems behind your gateway to build IPsec tunnels that pass through the gateway
This possibility is discussed in more detail later
filter incoming packets emerging from KLIPS.
Firewall rules can recognise packets emerging from IPsec. They are marked as arriving on an interface such as ipsec0, rather than eth0, ppp0 or whatever.

It is therefore reasonably straightforward to filter these packets in whatever way suits your situation.

Modifying existing rules

In some cases rules that work fine before you add IPsec may require modification to work with IPsec.

This is especially likely for rules that deal with interfaces on the Internet side of your system. IPsec adds a new interface; often the rules must change to take account of that.

For example, consider the rules given in this section of the Netfilter documentation:

Most people just have a single PPP connection to the Internet, and don't
want anyone coming back into their network, or the firewall:

    ## Insert connection-tracking modules (not needed if built into kernel).
    # insmod ip_conntrack
    # insmod ip_conntrack_ftp

    ## Create chain which blocks new connections, except if coming from inside.
    # iptables -N block
    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
    # iptables -A block -m state --state NEW -i ! ppp0 -j ACCEPT
    # iptables -A block -j DROP

    ## Jump to that chain from INPUT and FORWARD chains.
    # iptables -A INPUT -j block
    # iptables -A FORWARD -j block

On an IPsec gateway, those rules may need to be modified. The above allows new connections from anywhere except ppp0. That means new connections from ipsec0 are allowed.

Do you want to allow anyone who can establish an IPsec connection to your gateway to initiate TCP connections to any service on your network? Almost certainly not if you are using opportunistic encryption. Quite possibly not even if you have only explicitly configured connections.

To disallow incoming connections from ipsec0, change the middle section above to:

    ## Create chain which blocks new connections, except if coming from inside.
    # iptables -N block
    # iptables -A block -m state --state ESTABLISHED,RELATED -j ACCEPT
    # iptables -A block -m state --state NEW -i ppp+ -j DROP
    # iptables -A block -m state --state NEW -i ipsec+ -j DROP
    # iptables -A block -m state --state NEW -i -j ACCEPT
    # iptables -A block -j DROP

The original rules accepted NEW connections from anywhere except ppp0. This version drops NEW connections from any PPP interface (ppp+) and from any ipsec interface (ipsec+), then accepts the survivors.

Of course, these are only examples. You will need to adapt them to your own situation.

Published rule sets

Several sets of firewall rules that work with FreeS/WAN are available.

Scripts based on Ranch's work

One user, Rob Hutton, posted his boot time scripts to the mailing list, and we included them in previous versions of this documentation. They are still available from our web site. However, they were for an earlier FreeS/WAN version so we no longer recommend them. Also, they had some bugs. See this message.

Those scripts were based on David Ranch's scripts for his "Trinity OS" for setting up a secure Linux. Check his home page for the latest version and for information on his book on securing Linux. If you are going to base your firewalling on Ranch's scripts, we recommend using his latest version, and sending him any IPsec modifications you make for incorporation into later versions.

The Seattle firewall

We have had several mailing lists reports of good results using FreeS/WAN with Seawall (the Seattle Firewall). See that project's home page on Sourceforge.

The RCF scripts

Another set of firewall scripts with IPsec support are the RCF or rc.firewall scripts. See their home page.

Asgard scripts

Asgard's Realm has set of firewall scripts with FreeS/WAN support, for 2.4 kernels and iptables.

User scripts from the mailing list

One user gave considerable detail on his scripts, including supporting IPX through the tunnel. His message was too long to conveniently be quoted here, so I've put it in a separate file.

Calling firewall scripts, named in ipsec.conf(5)

The ipsec.conf(5) configuration file has three pairs of parameters used to specify an interface between FreeS/WAN and firewalling code.

Note that using these is not required if you have a static firewall setup. In that case, you just set your firewall up at boot time (in a way that permits the IPsec connections you want) and do not change it thereafter. Omit all the FreeS/WAN firewall parameters and FreeS/WAN will not attempt to adjust firewall rules at all. See above for some information on appropriate scripts.

However, if you want your firewall rules to change when IPsec connections change, then you need to use these parameters.

Scripts called at IPsec start and stop

One pair of parmeters are set in the config setup section of the ipsec.conf(5) file and affect all connections:

prepluto=
script to be called before pluto(8) IKE daemon is started.
postpluto=
script to be called after pluto(8) IKE daemon is stopped.
These parameters allow you to change firewall parameters whenever IPsec is started or stopped.

They can also be used in other ways. For example, you might have prepluto add a module to your kernel for the secure network interface or make a dialup connection, and then have postpluto remove the module or take the connection down.

Scripts called at connection up and down

The other parameters are set in connection descriptions. They can be set in individual connection descriptions, and could even call different scripts for each connection for maximum flexibility. In most applications, however, it makes sense to use only one script and to call it from conn %default section so that it applies to all connections.

You can:

either
set leftfirewall=yes or rightfirewall=yes to use our supplied default script
or
assign a name in a leftupdown= or rightupdown= line to use your own script

Note that only one of these should be used. You cannot sensibly use both. Since our default script is obsolete (designed for firewalls using ipfwadm(8) on 2.0 kernels), most users who need this service will need to write a custom script.

The default script

We supply a default script named _updown.

leftfirewall=
rightfirewall=
indicates that the gateway is doing firewalling and that pluto(8) should poke holes in the firewall as required.

Set these to yes and Pluto will call our default script _updown with appropriate arguments whenever it:

The supplied default _updown script is appropriate for simple cases using the ipfwadm(8) firewalling package.

User-written scripts

You can also write your own script and have Pluto call it. Just put the script's name in one of these ipsec.conf(5) lines:

leftupdown=
rightupdown=
specifies a script to call instead of our default script _updown.

Your script should take the same arguments and use the same environment variables as _updown. See the "updown command" section of the ipsec_pluto(8) man page for details.

Note that you should not modify our _updown script in place . If you did that, then upgraded FreeS/WAN, the upgrade would install a new default script, overwriting your changes.

Scripts for ipchains or iptables

Our _updown is for firewalls using ipfwadm(8), the firewall code for the 2.0 series of Linux kernels. If you are using the more recent packages ipchains(8) (for 2.2 kernels) or iptables(8) (2.4 kernels), then you must do one of:

You can write a script to do whatever you need with firewalling. Specify its name in a [left|right]updown= parameter in ipsec.conf(5) and Pluto will automatically call it for you.

The arguments Pluto passes such a script are the same ones it passes to our default _updown script, so the best way to build yours is to copy ours and modify the copy.

Note, however, that you should not modify our _updown script in place. If you did that, then upgraded FreeS/WAN, the upgrade would install a new default script, overwriting your changes.

A complication: IPsec vs. NAT

Network Address Translation, also known as IP masquerading, is a method of allocating IP addresses dynamically, typically in circumstances where the total number of machines which need to access the Internet exceeds the supply of IP addresses.

Any attempt to perform NAT operations on IPsec packets between the IPsec gateways creates a basic conflict:

For AH, which authenticates parts of the packet header including source and destination IP addresses, this is fatal. If NAT changes those fields, AH authentication fails.

For IKE and ESP it is not necessarily fatal, but is certainly an unwelcome complication.

NAT on or behind the IPsec gateway works

This problem can be avoided by having the masquerading take place on or behind the IPsec gateway.

This can be done physically with two machines, one physically behind the other. A picture, using SG to indicate IPsec S ecurity Gateways, is:

      clients --- NAT ----- SG ---------- SG
                  two machines

In this configuration, the actual client addresses need not be given in the leftsubnet= parameter of the FreeS/WAN connection description. The security gateway just delivers packets to the NAT box; it needs only that machine's address. What that machine does with them does not affect FreeS/WAN.

A more common setup has one machine performing both functions:

      clients ----- NAT/SG ---------------SG
                  one machine

Here you have a choice of techniques depending on whether you want to make your client subnet visible to clients on the other end:

NAT between gateways is problematic

We recommend not trying to build IPsec connections which pass through a NAT machine. This setup poses problems:

      clients --- SG --- NAT ---------- SG

If you must try it, some references are:

Other references on NAT and IPsec

Other documents which may be relevant include:

Other complications

Of course simply allowing UDP 500 and ESP packets is not the whole story. Various other issues arise in making IPsec and packet filters co-exist and even co-operate. Some of them are summarised below.

IPsec through the gateway

Basic IPsec packet filtering rules deal only with packets addressed to or sent from your IPsec gateway.

It is a separate policy decision whether to permit such packets to pass through the gateway so that client machines can build end-to-end IPsec tunnels of their own. This may not be practical if you are using NAT (IP masquerade) on your gateway, and may conflict with some corporate security policies.

Where possible, allowing this is almost certainly a good idea. Using IPsec on an end-to-end basis is more secure than gateway-to-gateway.

Doing it is quite simple. You just need firewall rules that allow UDP port 500 and protocols 50 and 51 to pass through your gateway. If you wish, you can of course restrict this to certain hosts.

Preventing non-IPsec traffic

You can also filter everything but UDP port 500 and ESP or AH to restrict traffic to IPsec only, either for anyone communicating with your host or just for specific partners.

One application of this is for the telecommuter who might have:

     Sunset==========West------------------East ================= firewall --- the Internet
         home network      untrusted net        corporate network

The subnet on the right is 0.0.0.0/0, the whole Internet. The West gateway is set up so that it allows only IPsec packets to East in or out.

This configuration is used in AT&T Research's network. For details, see the papers links in our introduction.

Another application would be to set up firewall rules so that an internal machine, such as an employees-only web server, could not talk to the outside world except via specific IPsec tunnels.

Filtering packets from unknown gateways

It is possible to use firewall rules to restrict UDP 500, ESP and AH packets so that these packets are accepted only from known gateways. This is not strictly necessary since FreeS/WAN will discard packets from unknown gateways. You might, however, want to do it for any of a number of reasons. For example:

It is not possible to use only static firewall rules for this filtering if you do not know the other gateways' IP addresses in advance, for example if you have "road warriors" who may connect from a different address each time or if want to do opportunistic encryption to arbitrary gateways. In these cases, you can accept UDP 500 IKE packets from anywhere, then use the updown script feature of pluto(8) to dynamically adjust firewalling for each negotiated tunnel.

Firewall packet filtering does not much reduce the risk of a denial of service attack on FreeS/WAN. The firewall can drop packets from unknown gateways, but KLIPS does that quite efficiently anyway, so you gain little. The firewall cannot drop otherwise legitmate packets that fail KLIPS authentication, so it cannot protect against an attack designed to exhaust resources by making FreeS/WAN perform many expensive authentication operations.

In summary, firewall filtering of IPsec packets from unknown gateways is possible but not strictly necessary.

Other packet filters

When the IPsec gateway is also acting as your firewall, other packet filtering rules will be in play. In general, those are outside the scope of this document. See our Linux firewall links for information. There are a few types of packet, however, which can affect the operation of FreeS/WAN or of diagnostic tools commonly used with it. These are discussed below.

ICMP filtering

ICMP is the Internet Control Message Protocol. It is used for messages between IP implementations themselves, whereas IP used is used between the clients of those implementations. ICMP is, unsurprisingly, used for control messages. For example, it is used to notify a sender that a desination is not reachable, or to tell a router to reroute certain packets elsewhere.

ICMP handling is tricky for firewalls.

ICMP does not use ports. Messages are distinguished by a "message type" field and, for some types, by an additional "code" field. The definitive list of types and codes is on the IANA site.

One expert uses this definition for ICMP message types to be dropped at the firewall.

# ICMP types which lack socially redeeming value.
#  5     Redirect
#  9     Router Advertisement
# 10     Router Selection
# 15     Information Request
# 16     Information Reply
# 17     Address Mask Request
# 18     Address Mask Reply

badicmp='5 9 10 15 16 17 18'

A more conservative approach would be to make a list of allowed types and drop everything else.

Whichever way you do it, your ICMP filtering rules on a FreeS/WAN gateway should allow at least the following ICMP packet types:

echo (type 8)
echo reply (type 0)
These are used by ping(1). We recommend allowing both types through the tunnel and to or from your gateway's external interface, since ping(1) is an essential testing tool.

It is fairly common for firewalls to drop ICMP echo packets addressed to machines behind the firewall. If that is your policy, please create an exception for such packets arriving via an IPsec tunnel, at least during intial testing of those tunnels.

destination unreachable (type 3)
This is used, with code 4 (Fragmentation Needed and Don't Fragment was Set) in the code field, to control path MTU discovery. Since IPsec processing adds headers, enlarges packets and may cause fragmentation, an IPsec gateway should be able to send and receive these ICMP messages on both inside and outside interfaces.

UDP packets for traceroute

The traceroute(1) utility uses UDP port numbers from 33434 to approximately 33633. Generally, these should be allowed through for troubleshooting.

Some firewalls drop these packets to prevent outsiders exploring the protected network with traceroute(1). If that is your policy, consider creating an exception for such packets arriving via an IPsec tunnel, at least during intial testing of those tunnels.

UDP for L2TP

Windows 2000 does, and products designed for compatibility with it may, build L2TP tunnels over IPsec connections.

For this to work, you must allow UDP protocol 1701 packets coming out of your tunnels to continue to their destination. You can, and probably should, block such packets to or from your external interfaces, but allow them from ipsec0.

See also our Windows 2000 interoperation discussion.

How it all works: IPsec packet details

IPsec uses three main types of packet:

IKE uses the UDP protocol and port 500 .
Unless you are using only (less secure, not recommended) manual keying, you need IKE to negotiate connection parameters, acceptable algorithms, key sizes and key setup. IKE handles everything required to set up, rekey, repair or tear down IPsec connections.
ESP is protocol number 50
This is required for encrypted connections.
AH is protocol number 51
This can be used where only authentication, not encryption, is required.

All of those packets should have appropriate IPsec gateway addresses in both the to and from IP header fields. Firewall rules can check this if you wish, though it is not strictly necessary. This is discussed in more detail later.

IPsec processing of incoming packets authenticates them then removes the ESP or AH header and decrypts if necessary. Successful processing exposes an inner packet which is then delivered back to the firewall machinery, marked as having arrived on an ipsec[0-3] interface. Firewall rules can use that interface label to distinguish these packets from unencrypted packets which are labelled with the physical interface they arrived on (or perhaps with a non-IPsec virtual interface such as ppp0).

One of our users sent a mailing list message with a diagram of the packet flow.

ESP and AH do not have ports

Some protocols, such as TCP and UDP, have the notion of ports. Others protocols, including ESP and AH, do not. Quite a few IPsec newcomers have become confused on this point. There are no ports in the ESP or AH protocols, and no ports used for them. For these protocols, the idea of ports is completely irrelevant.

Header layout

The protocol numbers for ESP or AH are used in the 'next header' field of the IP header. On most non-IPsec packets, that field would have one of:

Each header in the sequence tells what the next header will be. IPsec adds headers for ESP or AH near the beginning of the sequence. The original headers are kept and the 'next header' fields adjusted so that all headers can be correctly interpreted.

For example, using [ ] to indicate data protected by ESP and unintelligible to an eavesdropper between the gateways:

Part of the ESP header itself is encrypted, which is why the [ indicating protected data appears in the middle of some lines above. The next header field of the ESP header is protected. This makes traffic analysis more difficult. The next header field would tell an eavesdropper whether your packet was UDP to the gateway, TCP to the gateway, or encapsulated IP. It is better not to give this information away. A clever attacker may deduce some of it from the pattern of packet sizes and timings, but we need not make it easy.

IPsec allows various combinations of these to match local policies, including combinations that use both AH and ESP headers or that nest multiple copies of these headers.

For example, suppose my employer has an IPsec VPN running between two offices so all packets travelling between the gateways for those offices are encrypted. If gateway policies allow it (The admins could block UDP 500 and protocols 50 and 51 to disallow it), I can build an IPsec tunnel from my desktop to a machine in some remote office. Those packets will have one ESP header throughout their life, for my end-to-end tunnel. For part of the route, however, they will also have another ESP layer for the corporate VPN's encapsulation. The whole header scheme for a packet on the Internet might be:

The first ESP (outermost) header is for the corporate VPN. The inner ESP header is for the secure machine-to-machine link.

DHR on the updown script

Here are some mailing list comments from pluto(8) developer Hugh Redelmeier on an earlier draft of this document:

There are many important things left out

- firewalling is important but must reflect (implement) policy.  Since
  policy isn't the same for all our customers, and we're not experts,
  we should concentrate on FW and MASQ interactions with FreeS/WAN.

- we need a diagram to show packet flow WITHIN ONE MACHINE, assuming
  IKE, IPsec, FW, and MASQ are all done on that machine.  The flow is
  obvious if the components are run on different machines (trace the
  cables).

  IKE input:
        + packet appears on public IF, as UDP port 500
        + input firewalling rules are applied (may discard)
        + Pluto sees the packet.

  IKE output:
        + Pluto generates the packet & writes to public IF, UDP port 500
        + output firewalling rules are applied (may discard)
        + packet sent out public IF

  IPsec input, with encapsulated packet, outer destination of this host:
        + packet appears on public IF, protocol 50 or 51.  If this
          packet is the result of decapsulation, it will appear
          instead on the paired ipsec IF.
        + input firewalling rules are applied (but packet is opaque)
        + KLIPS decapsulates it, writes result to paired ipsec IF
        + input firewalling rules are applied to resulting packet
          as input on ipsec IF
        + if the destination of the packet is this machine, the
          packet is passed on to the appropriate protocol handler.
          If the original packet was encapsulated more than once
          and the new outer destination is this machine, that
          handler will be KLIPS.
        + otherwise:
          * routing is done for the resulting packet.  This may well
            direct it into KLIPS for encoding or encrypting.  What
            happens then is described elsewhere.
          * forwarding firewalling rules are applied
          * output firewalling rules are applied
          * the packet is sent where routing specified

 IPsec input, with encapsulated packet, outer destination of another host:
        + packet appears on some IF, protocol 50 or 51
        + input firewalling rules are applied (but packet is opaque)
        + routing selects where to send the packet
        + forwarding firewalling rules are applied (but packet is opaque)
        + packet forwarded, still encapsulated

  IPsec output, from this host or from a client:
        + if from a client, input firewalling rules are applied as the
          packet arrives on the private IF
        + routing directs the packet to an ipsec IF (this is how the
          system decides KLIPS processing is required)
        + if from a client, forwarding firewalling rules are applied
        + KLIPS eroute mechanism matches the source and destination
          to registered eroutes, yielding a SPI group.  This dictates
          processing, and where the resulting packet is to be sent
          (the destinations SG and the nexthop).
        + output firewalling is not applied to the resulting
          encapsulated packet

- Until quite recently, KLIPS would double encapsulate packets that
  didn't strictly need to be.  Firewalling should be prepared for
  those packets showing up as ESP and AH protocol input packets on
  an ipsec IF.

- MASQ processing seems to be done as if it were part of the
  forwarding firewall processing (this should be verified).

- If a firewall is being used, it is likely the case that it needs to
  be adjusted whenever IPsec SAs are added or removed.  Pluto invokes
  a script to do this (and to adjust routing) at suitable times.  The
  default script is only suitable for ipfwadm-managed firewalls.  Under
  LINUX 2.2.x kernels, ipchains can be managed by ipfwadm (emulation),
  but ipchains more powerful if manipulated using the ipchains command.
  In this case, a custom updown script must be used.

  We think that the flexibility of ipchains precludes us supplying an
  updown script that would be widely appropriate.

Linux FreeS/WAN Troubleshooting Guide

Overview

This document covers several general places where you might have a problem:

  1. During install.
  2. During the negotiation process.
  3. Using an established connection.

This document also contains notes which expand on points made in these sections, and tips for problem reporting. If the other end of your connection is not FreeS/WAN, you'll also want to read our interoperation document.

1. During Install

1.1 RPM install gotchas

With the RPM method:

1.2 Problems installing from source

When installing from source, you may find these problems:

1.3 Install checks

ipsec verify checks a number of FreeS/WAN essentials. Here are some hints on what do to when your system doesn't check out:

ProblemStatus Action
ipsec not on-path 

Add /usr/sbin to your PATH.

Missing KLIPS supportcritical See this FAQ.
No RSA private key 

Follow these instructions to create an RSA key pair for your host. RSA keys are:

  • required for opportunistic encryption, and
  • our preferred method to authenticate pre-configured connections.
pluto not running critical
service ipsec start
No port 500 holecritical Open port 500 for IKE negotiation.
Port 500 check N/A Check that port 500 is open for IKE negotiation.
Failed DNS checks Opportunistic encryption requires information from DNS. To set this up, see our instructions.
No public IP address Check that the interface which you want to protect with IPSec is up and running.

1.3 Troubleshooting OE

OE should work with no local configuration, if you have posted DNS TXT records according to the instructions in our quickstart guide. If you encounter trouble, try these hints. We welcome additional hints via the users' mailing list.

SymptomProblem Action
You're running FreeS/WAN 2.01 (or later), and initiating a connection to FreeS/WAN 2.00 (or earlier). In your logs, you see a message like:
no RSA public key known for '192.0.2.13';
DNS search for KEY failed (no KEY record
for 13.2.0.192.in-addr.arpa.)
The older FreeS/WAN logs no error.
A protocol level incompatibility between 2.01 (or later) and 2.00 (or earlier) causes this error. It occurs when a FreeS/WAN 2.01 (or later) box for which no KEY record is posted attempts to initiate an OE connection to older FreeS/WAN versions (2.00 and earlier). Note that older versions can initiate to newer versions without this error. If you control the peer host, upgrade its FreeS/WAN to 2.01 (or later), and post new style TXT records for it. If not, but if you know its sysadmin, perhaps a quick note is in order. If neither option is possible, you can ease the transition by posting an old style KEY record (created with a command like "ipsec showhostkey --key") to the reverse map for the FreeS/WAN 2.01 (or later) box.
OE host is very slow to contact other hosts.Slow DNS service while running OE.It's a good idea to run a caching DNS server on your OE host, as outlined in this mailing list message. If your DNS servers are elsewhere, put their IPs in the clear policy group, and re-read groups with
ipsec auto --rereadgroups
Can't Opportunistically initiate for
192.0.2.2 to 192.0.2.3: no TXT record
for 13.2.0.192.in-addr.arpa.
Peer is not set up for OE.

None. Plenty of hosts on the Internet do not run OE. If, however, you have set OE up on that peer, this may indicate that you need to wait up to 48 hours for its DNS records to propagate.

ipsec verify does not find DNS records:
...
Looking for TXT in forward map:
                xy.example.com...[FAILED]
Looking for TXT in reverse map...[FAILED]
...
You also experience authentication failure:
Possible authentication failure:
no acceptable response to our
first encrypted message
DNS records are not posted or have not propagated.Did you post the DNS records necessary for OE? If not, do so using the instructions in our quickstart guide. If so, wait up to 48 hours for the DNS records to propagate.
ipsec verify does not find DNS records, and you experience authentication failure.For iOE, your ID does not match location of forward DNS record.In config setup , change myid= to match the forward DNS where you posted the record. Restart FreeS/WAN. For reference, see our iOE instructions.
ipsec verify finds DNS records, yet there is still authentication failure. ( ? )DNS records are malformed. Re-create the records and send new copies to your DNS administrator.
ipsec verify finds DNS records, yet there is still authentication failure. ( ? )DNS records show different keys for a gateway vs. its subnet hosts.All TXT records for boxes protected by an OE gateway must contain the gateway's public key. Re-create and re-post any incorrect records using these instructions.
OE gateway loses connectivity to its subnet. The gateway's routing table shows routes to the subnet through IPsec interfaces. The subnet is part of the private or block policy group on the gateway.Remove the subnet from the group, and reread groups with
ipsec auto --rereadgroups
OE does not work to hosts on the local LAN.This is a known issue.See this list of known issues with OE.
FreeS/WAN does not seem to be executing your default policy. In your logs, you see a message like:
/etc/ipsec.d/policies/iprivate-or-clear"
line 14: subnet "0.0.0.0/0",
source 192.0.2.13/32,
already "private-or-clear"
Fullnet in a policy group file defines your default policy. Fullnet should normally be present in only one policy group file. The fine print: you can have two default policies defined so long as they protect different local endpoints (e.g. the FreeS/WAN gateway and a subnet). Find all policies which contain fullnet with:
grep -F 0.0.0.0/0 /etc/ipsec.d/policies/*
then remove the unwanted occurrence(s).

2. During Negotiation

When you fail to bring up a tunnel, you'll need to find out:

before you can diagnose your problem .

2.1 Determine Connection State

Finding current state

You can see connection states (STATE_MAIN_I1 and so on) when you bring up a connection on the command line. If you have missed this, or brought up your connection automatically, use:

ipsec auto --status

The most relevant state is the last one reached.

What's this supposed to look like?

Negotiations should proceed though various states, in the processes of:

  1. IKE negotiations (aka Phase 1, Main Mode, STATE_MAIN_*)
  2. IPSEC negotiations (aka Phase 2, Quick Mode, STATE_QUICK_*)

These are done and a connection is established when you see messages like:

    000 #21: "myconn" STATE_MAIN_I4 (ISAKMP SA established)...
    000 #2: "myconn" STATE_QUICK_I2 (sent QI2, IPsec SA established)...

Look for the key phrases are "ISAKMP SA established" and "IPSec SA established", with the relevant connection name. Often, this happens at STATE_MAIN_I4 and STATE_QUICK_I2, respectively.

ipsec auto --status will tell you what states have been achieved, rather than the current state. Since determining the current state is rather more difficult to do, current state information is not available from Linux FreeS/WAN. If you are actively bringing a connection up, the status report's last states for that connection likely reflect its current state. Beware, though, of the case where a connection was correctly brought up but is now downed: Linux FreeS/WAN will not notice this until it attempts to rekey. Meanwhile, the last known state indicates that the connection has been established.

If your connection is stuck at STATE_MAIN_I1, skip straight to here.

2.2 Finding error text

Solving most errors will require you to find verbose error text, either on the command line or in the logs.

Verbose start for more information

Note that you can get more detail from ipsec auto using the --verbose flag:

    ipsec auto --verbose --up west-east

More complete information can be gleaned from the log files.

Debug levels count

The amount of description you'll get here depends on ipsec.conf debug settings, klipsdebug= and plutodebug=. When troubleshooting, set at least one of these to all, and when done, reset it to none so your logs don't fill up. Note that you must have enabled the klipsdebug compile-time option for the klipsdebug configuration switch to work.

For negotiation problems plutodebug is most relevant. klipsdebug applies mainly to attempts to use an already-established connection. See also this description of the division of duties within Linux FreeS/WAN.

After raising your debug levels, restart Linux FreeS/WAN to ensure that ipsec.conf is reread, then recreate the error to generate verbose logs.

ipsec barf for lots of debugging information

ipsec barf (8) collects a bunch of useful debugging information, including these logs Use the command

    ipsec barf > barf.west

to generate one.

Find the error

Search out the failure point in your logs. Are there a handful of lines which succinctly describe how things are going wrong or contrary to your expectation? Sometimes the failure point is not immediately obvious: Linux FreeS/WAN's errors are usually not marked "Error". Have a look in the FAQ for what some common failures look like.

Tip: problems snowball. Focus your efforts on the first problem, which is likely to be the cause of later errors.

Play both sides

Also find error text on the peer IPSec box. This gives you two perspectives on the same failure.

At times you will require information which only one side has. The peer can merely indicate the presence of an error, and its approximate point in the negotiations. If one side keeps retrying, it may be because there is a show stopper on the other side. Have a look at the other side and figure out what it doesn't like.

If the other end is not Linux FreeS/WAN, the principle is the same: replicate the error with its most verbose logging on, and capture the output to a file.

2.3 Interpreting a Negotiation Error

Connection stuck at STATE_MAIN_I1

This error commonly happens because IKE (port 500) packets, needed to negotiate an IPSec connection, cannot travel freely between your IPSec gateways. See our firewall document for details.

Other errors

Other errors require a bit more digging. Use the following resources:

If you have failed to solve your problem with the help of these resources, send a detailed problem report to the users list, following these guidelines.

3. Using a Connection

3.1 Orienting yourself

How do I know if it works?

Test your connection by sending packets through it. The simplest way to do this is with ping, but the ping needs to test the correct tunnel. See this example scenario if you don't understand this.

If your ping returns, test any other connections you've brought u all check out, great. You may wish to test with large packets for MTU problems.

ipsec barf is useful again

If your ping fails to return, generate an ipsec barf debugging report on each IPSec gateway. On a non-Linux FreeS/WAN implementation, gather equivalent information. Use this, and the tips in the next sections, to troubleshoot. Are you sure that both endpoints are capable of hearing and responding to ping?

3.2 Those pesky configuration errors

IPSec may be dropping your ping packets since they do not belong in the tunnels you have constructed:

In either case, you will often see a message like:

klipsdebug... no eroute

which we discuss in this FAQ.

Note:

3.3 Check Routing and Firewalling

If you've confirmed your configuration assumptions, the problem is almost certainly with routing or firewalling. Isolate the problem using interface statistics, firewall statistics, or a packet sniffer.

Background:

View Interface and Firewall Statistics

Interface reports and firewall statistics can help you track down lost packets at a glance. Check any firewall statistics you may be keeping on your IPSec gateways, for dropped packets.

Tip: You can take a snapshot of the packets processed by your firewall with:

    iptables -L -n -v

You can get creative with "diff" to find out what happens to a particular packet during transmission.

Both cat /proc/net/dev and ifconfig display interface statistics, and both are included in ipsec barf. Use either to check if any interface has dropped packets. If you find that one has, test whether this is related to your ping. While you ping continuously, print that interface's statistics several times. Does its drop count increase in proportion to the ping? If so, check why the packets are dropped there.

To do this, look at the firewall rules that apply to that interface. If the interface is an IPSec interface, more information may be available in the log. Grep for the word "drop" in a log which was created with klipsdebug=all as the error happened.

See also this discussion on interpreting ifconfig statistics.

3.4 When in doubt, sniff it out

If you have checked configuration assumptions, routing, and firewall rules, and your interface statistics yield no clue, it remains for you to investigate the mystery of the lost packet by the most thorough method: with a packet sniffer (providing, of course, that this is legal where you are working).

In order to detect packets on the ipsec virtual interfaces, you will need an up-to-date sniffer (tcpdump, ethereal, ksnuffle) on your IPSec gateway machines. You may also find it useful to sniff the ping endpoints.

Anticipate your packets' path

Ping, and examine each interface along the projected path, checking for your ping's arrival. If it doesn't get to the the next stop, you have narrowed down where to look for it. In this way, you can isolate a problem area, and narrow your troubleshooting focus.

Within a machine running Linux FreeS/WAN, this packet flow diagram will help you anticipate a packet's path.

Note that:

Once you isolate where the packet is lost, take a closer look at firewall rules, routing and configuration assumptions as they affect that specific area. If the packet is lost on an IPSec gateway, comb through klipsdebug output for anomalies.

If the packet goes through both gateways successfully and reaches the ping target, but does not return, suspect routing. Check that the ping target routes packets back to the IPSec gateway.

3.5 Check your logs

Here, too, log information can be useful. Start with the guidelines above.

For connection use problems, set klipsdebug=all. Note that you must have enabled the klipsdebug compile-time option to do this. Restart Linux FreeS/WAN so that it rereads ipsec.conf, then recreate the error condition. When searching through klipsdebug data, look especially for the keywords "drop" (as in dropped packets) and "error".

Often the problem with connection use is not software error, but rather that the software is behaving contrary to expectation.

Interpreting log text

To interpret the Linux FreeS/WAN log text you've found, use the same resources as indicated for troubleshooting connection negotiation: the FAQ , our background document, and the list archives. Looking in the KLIPS code is only for the very brave.

If you are still stuck, send a detailed problem report to the users' list.

3.6 More testing for the truly thorough

Large Packets

If each of your connections passed the ping test, you may wish to test by pinging with large packets (2000 bytes or larger). If it does not return, suspect MTU issues, and see this discussion.

Stress Tests

In most users' view, a simple ping test, and perhaps a large-packet ping test suffice to indicate a working IPSec connection.

Some people might like to do additional stress tests prior to production use. They may be interested in this testing protocol we use at interoperation conferences, aka "bakeoffs". We also have a testing directory that ships with the release.

4. Problem Reporting

4.1 How to ask for help

Ask for troubleshooting help on the users' mailing list, users@lists.freeswan.org. While sometimes an initial query with a quick description of your intent and error will twig someone's memory of a similar problem, it's often necessary to send a second mail with a complete problem report.

When reporting problems to the mailing list(s), please include:

Here are some good general guidelines on bug reporting: How To Ask Questions The Smart Way and How to Report Bugs Effectively.

4.2 Where to ask

To report a problem, send mail about it to the users' list. If you are certain that you have found a bug, report it to the bugs list. If you encounter a problem while doing your own coding on the Linux FreeS/WAN codebase and think it is of interest to the design team, notify the design list. When in doubt, default to the users' list. More information about the mailing lists is found here.

For a number of reasons -- including export-control regulations affecting almost any private discussion of encryption software -- we prefer that problem reports and discussions go to the lists, not directly to the team. Beware that the list goes worldwide; US citizens, read this important information about your export laws. If you're using this software, you really should be on the lists. To get onto them, visit lists.freeswan.org.

If you do send private mail to our coders or want a private reply from them, please make sure that the return address on your mail (From or Reply-To header) is a valid one. They have more important things to do than to unravel addresses that have been mangled in an attempt to confuse spammers.

5. Additional Notes on Troubleshooting

The following sections supplement the Guide: information available on your system; testing between security gateways; ifconfig reports for KLIPS debugging; using GDB on Pluto.

5.1 Information available on your system

Logs used

Linux FreeS/WAN logs to:

Check both places to get full information. If you find nothing, check your syslogd.conf(5) to see where your /etc/syslog.conf or equivalent is directing authpriv messages.

man pages provided

ipsec.conf(5)
Manual page for IPSEC configuration file.
ipsec(8)
Primary man page for ipsec utilities.

Other man pages are on this list and in

Status information

ipsec auto --status
Command to get status report from running system. Displays Pluto's state. Includes the list of connections which are currently "added" to Pluto's internal database; lists state objects reflecting ISAKMP and IPsec SAs being negotiated or installed.
ipsec look
Brief status info.
ipsec barf
Copious debugging info.

5.2 Testing between security gateways

Sometimes you need to test a subnet-subnet tunnel. This is a tunnel between two security gateways, which protects traffic on behalf of the subnets behind these gateways. On this network:

     Sunset==========West------------------East=========Sunrise
                     IPSec gateway         IPSec gateway
           local net       untrusted net       local net

you might name this tunnel sunset-sunrise. You can test this tunnel by having a machine behind one gateway ping a machine behind the other gateway, but this is not always convenient or even possible.

Simply pinging one gateway from the other is not useful. Such a ping does not normally go through the tunnel. The tunnel handles traffic between the two protected subnets, not between the gateways . Depending on the routing in place, a ping might

Neither event tells you anything about the tunnel. You can explicitly create an eroute to force such packets through the tunnel, or you can create additional tunnels as described in our configuration document, but those may be unnecessary complications in your situation.

The trick is to explicitly test between both gateways' private-side IP addresses. Since the private-side interfaces are on the protected subnets, the resulting packets do go via the tunnel. Use either ping -I or traceroute -i, both of which allow you to specify a source interface. (Note: unsupported on older Linuxes). The same principles apply for a road warrior (or other) case where only one end of your tunnel is a subnet.

5.3 ifconfig reports for KLIPS debugging

When diagnosing problems using ifconfig statistics, you may wonder what type of activity increments a particular counter for an ipsecN device. Here's an index, posted by KLIPS developer Richard Guy Briggs:

Here is a catalogue of the types of errors that can occur for which
statistics are kept when transmitting and receiving packets via klips.
I notice that they are not necessarily logged in the right counter.
. . .

Sources of ifconfig statistics for ipsec devices

rx-errors:
- packet handed to ipsec_rcv that is not an ipsec packet.
- ipsec packet with payload length not modulo 4.
- ipsec packet with bad authenticator length.
- incoming packet with no SA.
- replayed packet.
- incoming authentication failed.
- got esp packet with length not modulo 8.

tx_dropped:
- cannot process ip_options.
- packet ttl expired.
- packet with no eroute.
- eroute with no SA.
- cannot allocate sk_buff.
- cannot allocate kernel memory.
- sk_buff internal error.


The standard counters are:

struct enet_statistics
{
        int        rx_packets;                /* total packets received */
        int        tx_packets;                /* total packets transmitted */
        int        rx_errors;                /* bad packets received */
        int        tx_errors;                /* packet transmit problems */
        int        rx_dropped;                /* no space in linux buffers */
        int        tx_dropped;                /* no space available in linux */
        int        multicast;                /* multicast packets received */
        int        collisions;

        /* detailed rx_errors: */
        int        rx_length_errors;
        int        rx_over_errors;                /* receiver ring buff overflow */
        int        rx_crc_errors;                /* recved pkt with crc error */
        int        rx_frame_errors;        /* recv'd frame alignment error */
        int        rx_fifo_errors;                /* recv'r fifo overrun */
        int        rx_missed_errors;        /* receiver missed packet */

        /* detailed tx_errors */
        int        tx_aborted_errors;
        int        tx_carrier_errors;
        int        tx_fifo_errors;
        int        tx_heartbeat_errors;
        int        tx_window_errors;
};

of which I think only the first 6 are useful.

5.4 Using GDB on Pluto

You may need to use the GNU debugger, gdb(1), on Pluto. This should be necessary only in unusual cases, for example if you encounter a problem which the Pluto developer cannot readily reproduce or if you are modifying Pluto.

Here are the Pluto developer's suggestions for doing this:

Can you get a core dump and use gdb to find out what Pluto was doing
when it died?

To get a core dump, you will have to set dumpdir to point to a
suitable directory (see ipsec.conf(5)).

To get gdb to tell you interesting stuff:
        $ script
        $ cd dump-directory-you-chose
        $ gdb /usr/lib/ipsec/pluto core
        (gdb) where
        (gdb) quit
        $ exit

The resulting output will have been captured by the script command in
a file called "typescript".  Send it to the list.

Do not delete the core file.  I may need to ask you to print out some
more relevant stuff.

Note that the dumpdir parameter takes effect only when the IPsec subsystem is restarted -- reboot or ipsec setup restart.




Linux FreeS/WAN Compatibility Guide

Much of this document is quoted directly from the Linux FreeS/WAN mailing list. Thanks very much to the community of testers, patchers and commenters there, especially the ones quoted below but also various contributors we haven't quoted.

Implemented parts of the IPsec Specification

In general, do not expect Linux FreeS/WAN to do everything yet. This is a work-in-progress and some parts of the IPsec specification are not yet implemented.

In Linux FreeS/WAN

Things we do, as of version 1.96:

All combinations of implemented transforms are supported. Note that some form of packet-level authentication is required whenever encryption is used. Without it, the encryption will not be secure.

Deliberately omitted

We do not implement everything in the RFCs because some of those things are insecure. See our discussions of avoiding bogus security.

Things we deliberately omit which are required in the RFCs are:

Since these are the only encryption algorithms and DH group the RFCs require, it is possible in theory to have a standards-conforming implementation which will not interpoperate with FreeS/WAN. Such an implementation would be inherently insecure, so we do not consider this a problem.

Anyway, most implementations sensibly include more secure options as well, so dropping null encryption, single DES and Group 1 does not greatly hinder interoperation in practice.

We also do not implement some optional features allowed by the RFCs:

In theory, this should cause no interoperation problems since all implementations are required to support the more secure main mode, whether or not they also allow aggressive mode.

In practice, it does sometimes produce problems with implementations such as Windows 2000 where aggressive mode is the default. Typically, these are easily solved with a configuration change that overrides that default.

Not (yet) in Linux FreeS/WAN

Things we don't yet do, as of version 1.96:

Our PF-Key implementation

We use PF-key Version Two for communication between the KLIPS kernel code and the Pluto Daemon. PF-Key v2 is defined by RFC 2367.

The "PF" stands for Protocol Family. PF-Inet defines a kernel/userspace interface for the TCP/IP Internet protocols (TCP/IP), and other members of the PF series handle Netware, Appletalk, etc. PF-Key is just a PF for key-related matters.

PF-Key portability

PF-Key came out of Berkeley Unix work and is used in the various BSD IPsec implementations, and in Solaris. This means there is some hope of porting our Pluto(8) to one of the BSD distributions, or of running their photurisd(8) on Linux if you prefer Photuris key management over IKE.

It is, however, more complex than that. The PK-Key RFC deliberately deals only with keying, not policy management. The three PF-Key implementations we have looked at -- ours, OpenBSD and KAME -- all have extensions to deal with security policy, and the extensions are different. There have been discussions aimed at sorting out the differences, perhaps for a version three PF-Key spec. All players are in favour of this, but everyone involved is busy and it is not clear whether or when these discussions might bear fruit.

Kernels other than the latest 2.2.x and 2.4.y

We develop and test on Redhat Linux using the most recent kernel in the 2.2 and 2.4 series. In general, we recommend you use the latest kernel in one of those series. Complications and caveats are discussed below.

2.0.x kernels

Consider upgrading to the 2.2 kernel series. If you want to stay with the 2.0 series, then we strongly recommend 2.0.39. Some useful security patches were added in 2.0.38.

Various versions of the code have run at various times on most 2.0.xx kernels, but the current version is only lightly tested on 2.0.39, and not at all on older kernels.

Some of our patches for older kernels are shipped in 2.0.37 and later, so they are no longer provided in FreeS/WAN. This means recent versions of FreeS/WAN will probably not compile on anything earlier than 2.0.37.

2.2 and 2.4 kernels

FreeS/WAN 1.0
ran only on 2.0 kernels
FreeS/WAN 1.1 to 1.8
ran on 2.0 or 2.2 kernels
ran on some development kernels, 2.3 or 2.4-test
FreeS/WAN 1.9 to 1.96
runs on 2.0, 2.2 or 2.4 kernels

In general, we suggest the latest 2.2 kernel or 2.4 for production use.

Of course no release can be guaranteed to run on kernels more recent than it is, so quite often there will be no stable FreeS/WAN for the absolute latest kernel. See the FAQ for discussion.

Intel Linux distributions other than Redhat

We develop and test on Redhat 6.1 for 2.2 kernels, and on Redhat 7.1 or 7.2 for 2.4, so minor changes may be required for other distributions.

Redhat 7.0

There are some problems with FreeS/WAN on Redhat 7.0. They are soluble, but we recommend you upgrade to a later Redhat instead..

Redhat 7 ships with two compilers.

Kernel Makefiles have gcc as a default, and must be adjusted to use kgcc before a kernel will compile on 7.0. This mailing list message gives details:

Subject: Re: AW: Installing IPsec on Redhat 7.0
   Date: Thu, 1 Feb 2001 14:32:52 -0200 (BRST)
  From: Mads Rasmussen <mads@cit.com.br>
 
> From www.redhat.com/support/docs/gotchas/7.0/gotchas-7-6.html#ss6.1

cd to /usr/src/linux and open the Makefile in your favorite editor. You
will need to look for a line similar to this:

CC = $(CROSS_COMPILE)gcc -D__KERNEL__ -I$(HPATH)

This line specifies which C compiler to use to build the kernel. It should
be changed to:

CC = $(CROSS_COMPILE)kgcc -D__KERNEL__ -I$(HPATH)

for Red Hat Linux 7. The kgcc compiler is egcs 2.91.66. From here you can
proceed with the typical compiling steps.

Check the mailing list archive for more recent news.

SuSE Linux

SuSE 6.3 and later versions, at least in Europe, ship with FreeS/WAN included.

FreeS/WAN packages distributed for SuSE 7.0-7.2 were somehow miscompiled. You can find fixed packages on Kurt Garloff's page.

Here are some notes for an earlier SuSE version.

SuSE Linux 5.3

Date: Mon, 30 Nov 1998
From: Peter Onion <ponion@srd.bt.co.uk>

... I got Saturdays snapshot working between my two SUSE5.3 machines at home.

The mods to the install process are quite simple.  From memory and looking at
the files on the SUSE53 machine here at work....

And extra link in each of the /etc/init.d/rc?.d directories called K35ipsec
which SUSE use to shut a service down.

A few mods in /etc/init.d/ipsec  to cope with the different places that SUSE
put config info, and remove the inculsion of /etc/rc.d/init.d/functions and .
/etc/sysconfig/network as they don't exists and 1st one isn't needed anyway.

insert ". /etc/rc.config" to pick up the SUSE config info and use 

  if test -n "$NETCONFIG" -a "$NETCONFIG" != "YAST_ASK" ; then

to replace 

  [ ${NETWORKING} = "no" ] && exit 0

Create /etc/sysconfig  as SUSE doesn't have one.

I think that was all (but I prob forgot something)....

You may also need to fiddle initialisation scripts to ensure that /var/run/pluto.pid is removed when rebooting. If this file is present, Pluto does not come up correctly.

Slackware

Subject: Re: linux-IPsec: Slackware distribution
  Date:  Thu, 15 Apr 1999 12:07:01 -0700
  From:  Evan Brewer <dmessiah@silcon.com>

> Very shortly, I will be needing to install IPsec on at least gateways that
> are running Slackware. . . .

The only trick to getting it up is that on the slackware dist there is no
init.d directory in /etc/rc.d .. so create one.  Then, what I do is take the
IPsec startup script which normally gets put into the init.d directory, and
put it in /etc/rc.d and name ir rc.ipsec .. then I symlink it to the file
in init.d.  The only file in the dist you need to really edit is the
utils/Makefile, setup4:

Everything else should be just fine.

A year or so later:

Subject: Re: HTML Docs- Need some cleanup?
   Date: Mon, 8 Jan 2001
   From: Jody McIntyre <jodym@oeone.com>

I have successfully installed FreeS/WAN on several Slackware 7.1 machines.
FreeS/WAN installed its rc.ipsec file in /etc/rc.d.  I had to manually call
this script from rc.inet2.  This seems to be an easier method than Evan
Brewer's.

Debian

A recent (Nov 2001) mailing list points to a web page on setting up several types of tunnel, including IPsec, on Debian.

Some older information:

Subject: FreeS/WAN 1.0 on Debian 2.1
   Date: Tue, 20 Apr 1999
  From:  Tim Miller <cerebus+counterpane@haybaler.sackheads.org>

        Compiled and installed without error on a Debian 2.1 system
with kernel-source-2.0.36 after pointing RCDIR in utils/Makefile to
/etc/init.d.

        /var/lock/subsys/ doesn't exist on Debian boxen, needs to be
created; not a fatal error.

        Finally, IPsec scripts appear to be dependant on GNU awk
(gawk); the default Debian awk (mawk-1.3.3-2) had fatal difficulties.
With gawk installed and /etc/alternatives/awk linked to /usr/bin/gawk
operation appears flawless.

The scripts in question have been modified since this was posted. Awk versions should no longer be a problem.

Caldera

Subject: Re: HTML Docs- Need some cleanup?
   Date: Mon, 08 Jan 2001
   From: Andy Bradford <andyb@calderasystems.com>

On Sun, 07 Jan 2001 22:59:05 EST, Sandy Harris wrote:

>     Intel Linux distributions other than Redhat 5.x and 6.x 
>         Redhat 7.0 
>         SuSE Linux 
>             SuSE Linux 5.3 
>         Slackware 
>         Debian 

Can you please include Caldera in this list?  I have tested it since 
FreeS/Wan 1.1 and it works great with our systems---provided one 
follows the FreeS/Wan documentation. :-)

Thank you,
Andy

CPUs other than Intel

FreeS/WAN has been run sucessfully on a number of different CPU architectures. If you have tried it on one not listed here, please post to the mailing list.

Corel Netwinder (StrongARM CPU)

Subject: linux-ipsec: Netwinder diffs
Date: Wed, 06 Jan 1999
From: rhatfield@plaintree.com

I had a mistake in my IPsec-auto, so I got things working this morning.

Following are the diffs for my changes.  Probably not the best and cleanest way 
of doing it, but it works. . . . 

These diffs are in the 0.92 and later distributions, so these should work out-of-the-box on Netwinder.

Yellow Dog Linux on Power PC

Subject:  Compiling FreeS/WAN 1.1 on YellowDog Linux (PPC)
   Date:  11 Dec 1999
   From:  Darron Froese <darron@fudgehead.com>

I'm summarizing here for the record - because it's taken me many hours to do
this (multiple times) and because I want to see IPsec on more linuxes than
just x86.

Also, I can't remember if I actually did summarize it before... ;-) I'm
working too many late hours.

That said - here goes.

1. Get your linux kernel and unpack into /usr/src/linux/ - I used 2.2.13.
<http://www.kernel.org/pub/linux/kernel/v2.2/linux-2.2.13.tar.bz2>

2. Get FreeS/WAN and unpack into /usr/src/freeswan-1.1
<ftp://ftp.xs4all.nl/pub/crypto/freeswan/freeswan-1.1.tar.gz>

3. Get the gmp src rpm from here:
<ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm>

4. Su to root and do this: rpm --rebuild gmp-2.0.2-9a.src.rpm

You will see a lot of text fly by and when you start to see the rpm
recompiling like this:

Executing: %build
+ umask 022
+ cd /usr/src/redhat/BUILD
+ cd gmp-2.0.2
+ libtoolize --copy --force
Remember to add `AM_PROG_LIBTOOL' to `configure.in'.
You should add the contents of `/usr/share/aclocal/libtool.m4' to
`aclocal.m4'.
+ CFLAGS=-O2 -fsigned-char
+ ./configure --prefix=/usr

Hit Control-C to stop the rebuild. NOTE: We're doing this because for some
reason the gmp source provided with FreeS/WAN 1.1 won't build properly on
ydl.

cd /usr/src/redhat/BUILD/
cp -ar gmp-2.0.2 /usr/src/freeswan-1.1/
cd /usr/src/freeswan-1.1/
rm -rf gmp
mv gmp-2.0.2 gmp

5. Open the freeswan Makefile and change the line that says:
KERNEL=$(b)zimage (or something like that) to
KERNEL=vmlinux

6. cd ../linux/

7. make menuconfig
Select an option or two and then exit - saving your changes.

8. cd ../freeswan-1.1/ ; make menugo

That will start the whole process going - once that's finished compiling,
you have to install your new kernel and reboot.

That should build FreeS/WAN on ydl (I tried it on 1.1).
And a later message on the same topic:
Subject: Re: FreeS/WAN, PGPnet and E-mail
   Date: Sat, 22 Jan 2000
   From: Darron Froese <darron@fudgehead.com>

on 1/22/00 6:47 PM, Philip Trauring at philip@trauring.com wrote:

> I have a PowerMac G3 ...

The PowerMac G3 can run YDL 1.1 just fine. It should also be able to run
FreeS/WAN 1.2patch1 with a couple minor modifications:

1. In the Makefile it specifies a bzimage for the kernel compile - you have
to change that to vmlinux for the PPC.

2. The gmp source that comes with FreeS/WAN (for whatever reason) fails to
compile. I have gotten around this by getting the gmp src rpm from here:

ftp://ftp.yellowdoglinux.com//pub/yellowdog/champion-1.1/SRPMS/SRPMS/gmp-2.0.2-9a.src.rpm

If you rip the source out of there - and place it where the gmp source
resides it will compile just fine.

FreeS/WAN no longer includes GMP source.

Mklinux

One user reports success on the Mach-based micro kernel Linux.

Subject: Smiles on sparc and ppc
   Date: Fri, 10 Mar 2000
   From: Jake Hill <jah@alien.bt.co.uk>

You may or may not be interested to know that I have successfully built
FreeS/WAN on a number of non intel alpha architectures; namely on ppc
and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
works, mostly, with few changes.

Alpha 64-bit processors

Subject: IT WORKS (again) between intel & alpha :-)))))
   Date: Fri, 29 Jan 1999
   From: Peter Onion <ponion@srd.bt.co.uk>

Well I'm happy to report that I've got an IPsec connection between by intel & alpha machines again :-))

If you look back on this list to 7th of December I wrote...

-On 07-Dec-98 Peter Onion wrote:
-> 
-> I've about had enuf of wandering around inside the kernel trying to find out
-> just what is corrupting outgoing packets...
-
-Its 7:30 in the evening .....
-
-I FIXED IT  :-))))))))))))))))))))))))))))))))
-
-It was my own fault :-((((((((((((((((((
-
-If you ask me very nicly I'll tell you where I was a little too over keen to
-change unsigned long int __u32 :-)  OPSE ...
-
-So tomorrow it will full steam ahead to produce a set of diffs/patches against
-0.91 
-
-Peter Onion.

In general (there have been some glitches), FreeS/WAN has been running on Alphas since then.

Sun SPARC processors

Several users have reported success with FreeS/WAN on SPARC Linux. Here is one mailing list message:

Subject: Smiles on sparc and ppc
   Date: Fri, 10 Mar 2000
   From: Jake Hill <jah@alien.bt.co.uk>

You may or may not be interested to know that I have successfully built
FreeS/WAN on a number of non intel alpha architectures; namely on ppc
and sparc and also on osfmach3/ppc (MkLinux). I can report that it just
works, mostly, with few changes.

I have a question, before I make up some patches. I need to hack
gmp/mpn/powerpc32/*.s to build them. Is this ok? The changes are
trivial, but could I also use a different version of gmp? Is it vanilla
here?

I guess my only real headache is from ipchains, which appears to stop
running when IPsec has been started for a while. This is with 2.2.14 on
sparc.

This message, from a different mailing list, may be relevant for anyone working with FreeS/WAN on Suns:

Subject: UltraSPARC DES assembler
   Date: Thu, 13 Apr 2000
   From: svolaf@inet.uni2.dk (Svend Olaf Mikkelsen)
     To: coderpunks@toad.com

An UltraSPARC assembler version of the LibDES/SSLeay/OpenSSL des_enc.c
file is available at http://inet.uni2.dk/~svolaf/des.htm.

This brings DES on UltraSPARC from slower than Pentium at the same
clock speed to significantly faster.

MIPS processors

We know FreeS/WAN runs on at least some MIPS processors because Lasat manufacture an IPsec box based on an embedded MIPS running Linux with FreeS/WAN. We have no details.

Transmeta Crusoe

The Merilus Firecard, a Linux firewall on a PCI card, is based on a Crusoe processor and supports FreeS/WAN.

Motorola Coldfire

Subject: Re: Crypto hardware support
   Date: Mon, 03 Jul 2000
   From: Dan DeVault <devault@tampabay.rr.com>

.... I have been running
uClinux with FreeS/WAN 1.4 on a system built by Moreton Bay  (
http://www.moretonbay.com )  and it was using a Coldfire processor
and was able to do the Triple DES encryption at just about
1 mbit / sec rate.......  they put a Hi/Fn 7901 hardware encryption
chip on their board and now their system does over 25 mbit of 3DES
encryption........ pretty significant increase if you ask me.

Multiprocessor machines

FreeS/WAN is designed to work on SMP (symmetric multi-processing) Linux machines and is regularly tested on dual processor x86 machines.

We do not know of any testing on multi-processor machines with other CPU architectures or with more than two CPUs. Anyone who does test this, please report results to the mailing list .

The current design does not make particularly efficient use of multiprocessor machines; some of the kernel work is single-threaded.

Support for crypto hardware

Supporting hardware cryptography accelerators has not been a high priority for the development team because it raises a number of fairly complex issues:

That said, we have a report of FreeS/WAN working with one crypto accelerator and some work is going on to modify KLIPS to create a clean generic interface to such products. See this web page for some of the design discussion.

More recently, a patch to support some hardware accelerators has been posted:

Subject: [Design] [PATCH] H/W acceleration patch
   Date: Tue, 18 Sep 2001
   From: "Martin Gadbois" <martin.gadbois@colubris.com>
 
Finally!!
Here's a web site with H/W acceleration patch for FreeS/WAN 1.91, including
S/W and Hifn 7901 crypto support.

http://sources.colubris.com/

Martin Gadbois

Hardware accelerators could take performance well beyond what FreeS/WAN can do in software (discussed here ). Here is some discussion off the IETF IPsec list, October 2001:

 ... Currently shipping chips deliver, 600 mbps throughput on a single
 stream of 3DES IPsec traffic.  There are also chips that use multiple
 cores to do 2.4 gbps.  We (Cavium) and others have announced even faster
 chips. ... Mid 2002 versions will handle at line rate (OC48 and OC192)
 IPsec and SSL/TLS traffic not only 3DES CBC but also AES and arc4.

The patches to date support chips that have been in production for some time, not the state-of-the-art latest-and-greatest devices described in that post. However, they may still outperform software and they almost certainly reduce CPU overhead.

IP version 6 (IPng)

The Internet currently runs on version four of the IP protocols. IPv4 is what is in the standard Linux IP stack, and what FreeS/WAN was built for. In IPv4, IPsec is an optional feature.

The next version of the IP protocol suite is version six, usually abbreviated either as "IPv6" or as "IPng" for "IP: the next generation". For IPv6, IPsec is a required feature. Any machine doing IPv6 is required to support IPsec, much as any machine doing (any version of) IP is required to support ICMP.

There is a Linux implementation of IPv6 in Linux kernels 2.2 and above. For details, see the FAQ. It does not yet support IPsec. The USAGI project are also working on IPv6 for Linux.

FreeS/WAN was originally built for the current standard, IPv4, but we are interested in seeing it work with IPv6. Some progress has been made, and a patched version with IPv6 support is available. For more recent information, check the mailing list.

IPv6 background

IPv6 has been specified by an IETF working group. The group's page lists over 30 RFCs to date, and many Internet Drafts as well. The overview is RFC 2460. Major features include:

A number of projects are working on IPv6 implementation. A prominent Open Source effort is KAME, a collaboration among several large Japanese companies to implement IPv6 for Berkeley Unix. Other major players are also working on IPv6. For example, see pages at:

The 6bone (IPv6 backbone) testbed network has been up for some time. There is an active IPv6 user group.

One of the design goals for IPv6 was that it must be possible to convert from v4 to v6 via a gradual transition process. Imagine the mess if there were a "flag day" after which the entire Internet used v6, and all software designed for v4 stopped working. Almost every computer on the planet would need major software changes! There would be huge costs to replace older equipment. Implementers would be worked to death before "the day", systems administrators and technical support would be completely swamped after it. The bugs in every implementation would all bite simultaneously. Large chunks of the net would almost certainly be down for substantial time periods. ...

Fortunately, the design avoids any "flag day". It is therefore a little tricky to tell how quickly IPv6 will take over. The transition has certainly begun. For examples, see announcements from NTT and Nokia. However, it is not yet clear how quickly the process will gain momentum, or when it will be completed. Likely large parts of the Internet will remain with IPv4 for years to come.


Interoperating with FreeS/WAN

The FreeS/WAN project needs you! We rely on the user community to keep up to date. Mail users@lists.freeswan.org with your interop success stories.

Please note: Most of our interop examples feature Linux FreeS/WAN 1.x config files. You can convert them to 2.x files fairly easily with the patch in our Upgrading Guide.

Interop at a Glance

 FreeS/WAN VPNRoad Warrior OE
 PSKRSA SecretX.509
(requires patch)
NAT-Traversal
(requires patch)
Manual
Keying
  
More Compatible
FreeS/WAN   YesYes Yes YesYes YesYes
isakmpd (OpenBSD)   Yes  Yes Yes  No    
Kame (FreeBSD,
NetBSD, MacOSX)
aka racoon
 
YesYes Yes  Yes No
McAfee VPN
was PGPNet
 
YesYes Yes   YesNo
Microsoft
Windows 2000/XP
 
Yes Yes   Yes No
SSH Sentinel  Yes Yes Maybe  YesNo
Safenet SoftPK
/SoftRemote
 
Yes Yes   Yes No
Other
6Wind     Yes    No
Alcatel Timestep   Yes      No
Apple Macintosh
System 10+
 
MaybeYes Maybe Maybe  No
AshleyLaurent
VPCom
 
Yes     No
Borderware   Yes     No No
Check Point FW-1/VPN-1  Yes  Yes  Yes No
Cisco with 3DES   YesMaybe  Maybe   No
Equinux VPN Tracker
(for Mac OS X)
 
YesYes Yes Maybe  No
F-Secure   Yes   MaybeYes YesNo
Gauntlet GVPN   Yes  Yes    No
IBM AIX   Yes Maybe    No
IBM AS/400  Yes      No
Intel Shiva
LANRover/Net Structure
 
Yes     No
LanCom (formerly ELSA)  Yes      No
Linksys   Maybe  No  Yes No
Lucent  Partial      No
Netasq     Yes    No
netcelo     Yes    No
Netgear fvs318   Yes      No
Netscreen 100
or 5xp
 
Yes     MaybeNo
Nortel Contivity   Partial  YesMaybe   No
RadGuard   Yes      No
Raptor  Yes    Yes No
Redcreek Ravlin   Yes/Partial       No
SonicWall   Yes   MaybeNo No
Sun Solaris  Yes Yes  Yes No
Symantec   Yes      No
Watchguard
Firebox
 
Yes    Yes No
Xedia Access Point
/QVPN
 
Yes     No
Zyxel Zywall
/Prestige
 
Yes     No
 PSKRSA SecretX.509
(requires patch)
NAT-Traversal
(requires patch)
Manual
Keying
  
 FreeS/WAN VPNRoad Warrior OE

Key

YesPeople report that this works for them.
[Blank]We don't know.
NoWe have reason to believe it was, at some point, not possible to get this to work.
PartialPartial success. For example, a connection can be created from one end only.
Yes/Partial Mixed reports.
MaybeWe think the answer is "yes", but need confirmation.

Basic Interop Rules

Vanilla FreeS/WAN implements these parts of the IPSec specifications. You can add more with Super FreeS/WAN, but what we offer may be enough for many users.

We offer a set of proposals which is not user-adjustable, but covers all combinations that we can offer. FreeS/WAN always proposes triple DES encryption and Perfect Forward Secrecy (PFS). In addition, we propose Diffie Hellman groups 5 and 2 (in that order), and MD5 and SHA-1 hashes. We accept the same proposals, in the same order of preference.

Other interop notes:

Longer Stories

For More Compatible Implementations

FreeS/WAN

See our documentation at freeswan.org and the Super FreeS/WAN docs at freeswan.ca. Some user-written HOWTOs for FreeS/WAN-FreeS/WAN connections are listed in our Introduction.

See also:

Back to chart

isakmpd (OpenBSD)

OpenBSD FAQ: Using IPsec
Hans-Joerg Hoexer's interop Linux-OpenBSD (PSK)
Skyper's configuration (PSK)
French page with configs (X.509)

Back to chart

Kame

Kame homepage, with FAQ
NetBSD's IPSec FAQ
Ghislaine's post explaining some interop peculiarities

Itojun's Kame-FreeS/WAN interop tips (PSK)
Ghislaine Labouret's French page with links to matching FreeS/WAN and Kame configs (RSA)
Markus Wernig's HOWTO (X.509, BSD gateway)
Frodo's Kame-FreeS/WAN interop (X.509)
Kame as a WAVEsec client.

Back to chart

PGPNet/McAfee

Tim Carr's Windows Interop Guide (X.509)
Hans-Joerg Hoexer's Guide for Linux-PGPNet (PSK)
Kai Martius' instructions using RSA Key-Extractor Tool (RSA)
    Christian Zeng's page (RSA) based on Kai's work. English or German.
Oscar Delgado's PDF (X.509, no configs)
Ryan's HOWTO for FreeS/WAN-PGPNet (X.509). Through a Linksys Router with IPsec Passthru enabled.
Jean-Francois Nadeau's Practical Configuration (Road Warrior with PSK)
Wouter Prins' HOWTO (Road Warrior with X.509)

Rekeying problem with FreeS/WAN and older PGPNets

DHCP over IPSEC HOWTO for FreeS/WAN (requires X.509 and dhcprelay patches)

Back to chart

Microsoft Windows 2000/XP

Tim Carr's Windows Interop Guide (X.509)
James Carter's instructions (X.509, NAT-T)
Jean-Francois Nadeau's Net-net Configuration (PSK)
Telenor's Node-node Config (Transport-mode PSK)
Marcus Mueller's HOWTO using his VPN config tool (X.509). Tool also works with PSK.
Nate Carlson's HOWTO using same tool (Road Warrior with X.509). Unusually, FreeS/WAN is the Road Warrior here.
Oscar Delgado's PDF (X.509, no configs)
Tim Scannell's Windows XP Additional Checklist (X.509)

Microsoft's page on Win2k TCP/IP security features
Microsoft's Win2k IPsec debugging tips
MS VPN may fall back to 1DES

Back to chart

SSH Sentinel

SSH's Sentinel-FreeSWAN interop PDF (X.509)
Nadeem Hassan's SUSE-to-Sentinel article (Road warrior with X.509)
O-Zone's Italian HOWTO (Road Warrior, X.509, DHCP)

Back to chart

Safenet SoftPK/SoftRemote

Whit Blauvelt's SoftRemote tips
Tim Wilson's tips (X.509) Workaround for a "gotcha"

Jean-Francois Nadeau's Practical Configuration (Road Warrior with PSK)
Terradon Communications' PDF (Road Warrior with PSK)
Seaan.net's PDF (Road Warrior to Subnet, with PSK)
Red Baron Consulting's PDF (Road Warrior with X.509)

Back to chart

For Other Implementations

6Wind

French page with configs (X.509)

Back to chart

Alcatel Timestep

Alain Sabban's settings (PSK or PSK road warrior; through static NAT)
Derick Cassidy's configs (PSK)
David Kerry's Timestep settings (PSK)
Kevin Gerbracht's ipsec.conf (X.509)

Back to chart

Apple Macintosh System 10+

James Carter's instructions (X.509, NAT-T)

Back to chart

AshleyLaurent VPCom

Successful interop report, no details

Back to chart

Borderware

Philip Reetz' configs (PSK)
Borderware server does not support FreeS/WAN road warriors
Older Borderware may not support Diffie Hellman groups 2, 5

Back to chart

Check Point VPN-1 or FW-1

AERAsec's Firewall-1 NG site (PSK, X.509, Road Warrior with X.509, other algorithms)
     AERAsec's detailed Check Point-FreeS/WAN support matrix
Checkpoint.com PDF: Linux as a VPN Client to FW-1 (PSK)
PhoneBoy's Check Point FAQ (on Check Point only, not FreeS/WAN)

Chris Harwell's tips &FreeS/WAN configs (PSK)
Daniel Tombeil's configs (PSK)

Back to chart

Cisco

SANS Institute HOWTO (PSK). Detailed, with extensive references.
Short HOWTO (PSK)
French page with configs for Cisco IOS, PIX and VPN 3000 (X.509)
Dave McFerren's sample configs (PSK)
Wolfgang Tremmel's sample configs (PSK road warrior)
Old doc from Pete Davis, with William Watson's updated Tips (PSK)

Some PIX specific information:
Waikato Linux Users' Group HOWTO. Nice detail (PSK)
John Leach's configs (PSK)
Greg Robinson's settings (PSK)
Scott's ipsec.conf for PIX (PSK, FreeS/WAN side only)
Rick Trimble's PIX and FreeS/WAN settings (PSK)

Cisco VPN support page
Cisco IPsec information page

Back to chart

Equinux VPN tracker (for Mac OS X)

Equinux provides this excellent interop PDF (PSK, RSA, X.509).

Back to chart

F-Secure

pingworks.de's "Connecting F-Secure's VPN+ to Linux FreeS/WAN" (PSK road warrior)
    Same thing as PDF
Success report, no detail (PSK)
Success report, no detail (Manual)

Back to chart

Gauntlet GVPN

Richard Reiner's ipsec.conf (PSK)
Might work without that pesky firewall... (PSK)
In late July, 2003 Alexandar Antik reported success interoperating with Gauntlet 6.0 for Solaris (X.509). Unfortunately the message is not properly archived at this time.

Back to chart

IBM AIX

IBM's "Built-In Network Security with AIX" (PSK, X.509)
IBM's tip: importing Linux FreeS/WAN settings into AIX's ikedb (PSK)

Back to chart

IBM AS/400

Richard Welty's tips and tricks

Back to chart

Intel Shiva LANRover / Net Structure

Snowcrash's configs (PSK)
Old configs from an interop (PSK)
The day Shiva tickled a Pluto bug (PSK)
     Follow up: success!

Back to chart

LanCom (formerly ELSA)

Jakob Curdes successfully created a PSK connection with the LanCom 1612 in August 2003.

Back to chart

Linksys

As tunnel endpoint

Ken Bantoft's instructions (Road Warrior with PSK)
Nate Carlson's caveats

In IPsec passthrough mode

Sample HOWTO through a Linksys Router
Nadeem Hasan's configs
Brock Nanson's tips

Back to chart

Lucent

Partial success report; see also the next message in thread

Back to chart

Netasq

French page with configs (X.509)

Back to chart

Netcelo

French page with configs (X.509)

Back to chart

Netgear fvs318

John Morris' setup (PSK)

Back to chart

Netscreen 100 or 5xp

Errol Neal's settings (PSK)
Corey Rogers' configs (PSK, no PFS)
Jordan Share's configs (PSK, 2 subnets, through static NAT)
Set src proxy_id to your protected subnet/mask
French page with ipsec.conf, Netscreen screen shots (X.509, may need to revert to PSK...)

A report of a company using Netscreen with FreeS/WAN on a large scale (FreeS/WAN road warriors?)

Back to chart

Nortel Contivity

JJ Streicher-Bremer's mini HOWTO for old &new software. (PSK with two subnets)
French page with configs (X.509). This succeeds using the above X.509 tip.

Back to chart

Radguard

Marko Hausalo's configs (PSK). Note: These do create a connection, as you can see by "IPsec SA established".
Claudia Schmeing's comments

Back to chart

Raptor (NT or Solaris)

Peter Mazinger's settings (PSK)
Peter Gerland's configs (PSK)
Charles Griebel's configs (PSK).
Lumir Srch's tips (PSK)

John Hardy's configs (Manual)
Older Raptors want 3DES keys in 3 parts (Manual).
Different keys for each direction? (Manual)

Back to chart

Redcreek Ravlin

Back to chart

SonicWall

Paul Wouters' config (PSK)
Dilan Arumainathan's configuration (PSK)
Dariush's setup... only opens one way (PSK)
Andreas Steffen's tips (X.509)

Back to chart

Sun Solaris

Reports of some successful interops from a fellow @sun.com. See also these follow up posts.
Aleks Shenkman's configs (Manual in transport mode)

Back to chart

Symantec

Andreas Steffen's configs for Symantec 200R (PSK)

Back to chart

Watchguard Firebox

WatchGuard's HOWTO (PSK)
Ronald C. Riviera's Settings (PSK)
Walter Wickersham's Notes (PSK)
Max Enders' Configs (Manual)

Old known issue with auto keying
Tips on key generation and format (Manual)

Back to chart

Xedia Access Point/QVPN

Hybrid IPsec/L2TP connection settings (X.509)
Xedia's LAN-LAN links don't use multiple tunnels
     That explanation, continued

Back to chart

Zyxel

Zyxel's Zywall to FreeS/WAN instructions (PSK)
Zyxel's Prestige to FreeS/WAN instructions (PSK). Note: not all Prestige versions include VPN software.
Fabrice Cahen's HOWTO (PSK)
    

Back to chart


Performance of FreeS/WAN

The performance of FreeS/WAN is adequate for most applications.

In normal operation, the main concern is the overhead for encryption, decryption and authentication of the actual IPsec (ESP and/or AH) data packets. Tunnel setup and rekeying occur so much less frequently than packet processing that, in general, their overheads are not worth worrying about.

At startup, however, tunnel setup overheads may be significant. If you reboot a gateway and it needs to establish many tunnels, expect some delay. This and other issues for large gateways are discussed below.

Published material

The University of Wales at Aberystwyth has done quite detailed speed tests and put their results on the web.

Davide Cerri's thesis (in Italian) includes performance results for FreeS/WAN and for TLS. He posted an English summary on the mailing list.

Steve Bellovin used one of AT&T Research's FreeS/WAN gateways as his data source for an analysis of the cache sizes required for key swapping in IPsec. Available as text or PDF slides for a talk on the topic.

See also the NAI work mentioned in the next section.

Estimating CPU overheads

We can come up with a formula that roughly relates CPU speed to the rate of IPsec processing possible. It is far from exact, but should be usable as a first approximation.

An analysis of authentication overheads for high-speed networks, including some tests using FreeS/WAN, is on the NAI Labs site. In particular, see figure 3 in this PDF document. Their estimates of overheads, measured in Pentium II cycles per byte processed are:

IPsecauthenticationencryption cycles/byte
Linux IP stack alonenonono 5
IPsec without cryptoyesnono 11
IPsec, authentication onlyyesSHA-1no24
IPsec with encryptionyesyesyesnot tested

Overheads for IPsec with encryption were not tested in the NAI work, but Antoon Bosselaers' web page gives cost for his optimised Triple DES implementation as 928 Pentium cycles per block, or 116 per byte. Adding that to the 24 above, we get 140 cycles per byte for IPsec with encryption.

At 140 cycles per byte, a 140 MHz machine can handle a megabyte -- 8 megabits -- per second. Speeds for other machines will be proportional to this. To saturate a link with capacity C megabits per second, you need a machine running at C * 140/8 = C * 17.5 MHz.

However, that estimate is not precise. It ignores the differences between:

and does not account for some overheads you will almost certainly have:

so we suggest using C * 25 to get an estimate with a bit of a built-in safety factor.

This covers only IP and IPsec processing. If you have other loads on your gateway -- for example if it is also working as a firewall -- then you will need to add your own safety factor atop that.

This estimate matches empirical data reasonably well. For example, Metheringham's tests, described below, show a 733 topping out between 32 and 36 Mbit/second, pushing data as fast as it can down a 100 Mbit link. Our formula suggests you need at least an 800 to handle a fully loaded 32 Mbit link. The two results are consistent.

Some examples using this estimation method:

InterfaceMachine speed in MHz
TypeMbit per
second
Estimate
Mbit*25
Minimum IPSEC gatewayMinimum with other load

(e.g. firewall)

DSL125 MHz whatever you have133, or better if you have it
cable modem375 MHz
any link, light load 5125 MHz133200+, almost any surplus machine
Ethernet10250 MHz surplus 266 or 300500+
fast link, moderate load 20500 MHz500800+, any current off-the-shelf PC
T3 or E3451125 MHz 12001500+
fast Ethernet100 2500 MHz// not feasible with 3DES in software on current machines //
OC31553875 MHz

Such an estimate is far from exact, but should be usable as minimum requirement for planning. The key observations are:

Higher performance alternatives

AES is a new US government block cipher standard, designed to replace the obsolete DES. If FreeS/WAN using 3DES is not fast enough for your application, the AES patch may help.

To date (March 2002) we have had only one mailing list report of measurements with the patch applied. It indicates that, at least for the tested load on that user's network, AES roughly doubles IPsec throughput. If further testing confirms this, it may prove possible to saturate an OC3 link in software on a high-end box.

Also, some work is being done toward support of hardware IPsec acceleration which might extend the range of requirements FreeS/WAN could meet.

Other considerations

CPU speed may be the main issue for IPsec performance, but of course it isn't the only one.

You need good ethernet cards or other network interface hardware to get the best performance. See this ethernet information page and this Linux network driver page.

The current FreeS/WAN kernel code is largely single-threaded. It is SMP safe, and will run just fine on a multiprocessor machine ( discussion), but the load within the kernel is not shared effectively. This means that, for example to saturate a T3 -- which needs about a 1200 MHz machine -- you cannot expect something like a dual 800 to do the job.

On the other hand, SMP machines do tend to share loads well so -- provided one CPU is fast enough for the IPsec work -- a multiprocessor machine may be ideal for a gateway with a mixed load.

Many tunnels from a single gateway

FreeS/WAN allows a single gateway machine to build tunnels to many others. There may, however, be some problems for large numbers as indicated in this message from the mailing list:

Subject: Re: Maximum number of ipsec tunnels?
   Date: Tue, 18 Apr 2000
   From: "John S. Denker" <jsd@research.att.com>

Christopher Ferris wrote:

>> What are the maximum number ipsec tunnels FreeS/WAN can handle??

Henry Spencer wrote:

>There is no particular limit.  Some of the setup procedures currently
>scale poorly to large numbers of connections, but there are (clumsy)
>workarounds for that now, and proper fixes are coming.

1) "Large" numbers means anything over 50 or so.  I routinely run boxes
with about 200 tunnels.  Once you get more than 50 or so, you need to worry
about several scalability issues:

a) You need to put a "-" sign in syslogd.conf, and rotate the logs daily
not weekly.

b) Processor load per tunnel is small unless the tunnel is not up, in which
case a new half-key gets generated every 90 seconds, which can add up if
you've got a lot of down tunnels.

c) There's other bits of lore you need when running a large number of
tunnels.  For instance, systematically keeping the .conf file free of
conflicts requires tools that aren't shipped with the standard freeswan
package.

d) The pluto startup behavior is quadratic.  With 200 tunnels, this eats up
several minutes at every restart.   I'm told fixes are coming soon.

2) Other than item (1b), the CPU load depends mainly on the size of the
pipe attached, not on the number of tunnels.

It is worth noting that item (1b) applies only to repeated attempts to re-key a data connection (IPsec SA, Phase 2) over an established keying connection (ISAKMP SA, Phase 1). There are two ways to reduce this overhead using settings in ipsec.conf(5):

The overheads for establishing keying connections (ISAKMP SAs, Phase 1) are lower because for these Pluto does not perform expensive operations before receiving a reply from the peer.

A gateway that does a lot of rekeying -- many tunnels and/or low settings for tunnel lifetimes -- will also need a lot of random numbers from the random(4) driver.

Low-end systems

Even a 486 can handle a T1 line, according to this mailing list message:

Subject: Re: linux-ipsec: IPSec Masquerade
   Date: Fri, 15 Jan 1999 11:13:22 -0500
   From: Michael Richardson 

. . . A 486/66 has been clocked by Phil Karn to do
10Mb/s encryption.. that uses all the CPU, so half that to get some CPU,
and you have 5Mb/s. 1/3 that for 3DES and you get 1.6Mb/s....

and a piece of mail from project technical lead Henry Spencer:

Oh yes, and a new timing point for Sandy's docs...  A P60 -- yes, a 60MHz
Pentium, talk about antiques -- running a host-to-host tunnel to another
machine shows an FTP throughput (that is, end-to-end results with a real
protocol) of slightly over 5Mbit/s either way.  (The other machine is much
faster, the network is 100Mbps, and the ether cards are good ones... so
the P60 is pretty definitely the bottleneck.)

From the above, and from general user experience as reported on the list, it seems clear that a cheap surplus machine -- a reasonable 486, a minimal Pentium box, a Sparc 5, ... -- can easily handle a home office or a small company connection using any of:

If available, we suggest using a Pentium 133 or better. This should ensure that, even under maximum load, IPsec will use less than half the CPU cycles. You then have enough left for other things you may want on your gateway -- firewalling, web caching, DNS and such.

Measuring KLIPS

Here is some additional data from the mailing list.

Subject: FreeSWAN (specically KLIPS) performance measurements
   Date: Thu, 01 Feb 2001
   From: Nigel Metheringham <Nigel.Metheringham@intechnology.co.uk>

I've spent a happy morning attempting performance tests against KLIPS 
(this is due to me not being able to work out the CPU usage of KLIPS so 
resorting to the crude measurements of maximum throughput to give a 
baseline to work out loading of a box).

Measurements were done using a set of 4 boxes arranged in a line, each 
connected to the next by 100Mbit duplex ethernet.  The inner 2 had an 
ipsec tunnel between them (shared secret, but I was doing measurements 
when the tunnel was up and running - keying should not be an issue 
here).  The outer pair of boxes were traffic generators or traffic sink.

The crypt boxes are Compaq DL380s - Uniprocessor PIII/733 with 256K 
cache.  They have 128M main memory.  Nothing significant was running on 
the boxes other than freeswan.  The kernel was a 2.2.19pre7 patched 
with freeswan and ext3.

Without an ipsec tunnel in the chain (ie the 2 inner boxes just being 
100BaseT routers), throughput (measured with ttcp) was between 10644 
and 11320 KB/sec

With an ipsec tunnel in place, throughput was between 3268 and 3402 
KB/sec

These measurements are for data pushed across a TCP link, so the 
traffic on the wire between the 2 ipsec boxes would have been higher 
than this....

vmstat (run during some other tests, so not affecting those figures) on 
the encrypting box shows approx 50% system & 50% idle CPU - which I 
don't believe at all.  Interactive feel of the box was significantly 
sluggish.

I also tried running the kernel profiler (see man readprofile) during 
test runs.

A box doing primarily decrypt work showed basically nothing happening - 
I assume interrupts were off.
A box doing encrypt work showed the following:-
 Ticks Function                                   Load
 ~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    ~~~~~~
   956 total                                      0.0010
   532 des_encrypt2                               0.1330
   110 MD5Transform                               0.0443
    97 kmalloc                                    0.1880
    39 des_encrypt3                               0.1336
    23 speedo_interrupt                           0.0298
    14 skb_copy_expand                            0.0250
    13 ipsec_tunnel_start_xmit                    0.0009
    13 Decode                                     0.1625
    11 handle_IRQ_event                           0.1019
    11 .des_ncbc_encrypt_end                      0.0229
    10 speedo_start_xmit                          0.0188
     9 satoa                                      0.0225
     8 kfree                                      0.0118
     8 ip_fragment                                0.0121
     7 ultoa                                      0.0365
     5 speedo_rx                                  0.0071
     5 .des_encrypt2_end                          5.0000
     4 _stext                                     0.0140
     4 ip_fw_check                                0.0035
     2 rj_match                                   0.0034
     2 ipfw_output_check                          0.0200
     2 inet_addr_type                             0.0156
     2 eth_copy_and_sum                           0.0139
     2 dev_get                                    0.0294
     2 addrtoa                                    0.0143
     1 speedo_tx_buffer_gc                        0.0024
     1 speedo_refill_rx_buf                       0.0022
     1 restore_all                                0.0667
     1 number                                     0.0020
     1 net_bh                                     0.0021
     1 neigh_connected_output                     0.0076
     1 MD5Final                                   0.0083
     1 kmem_cache_free                            0.0016
     1 kmem_cache_alloc                           0.0022
     1 __kfree_skb                                0.0060
     1 ipsec_rcv                                  0.0001
     1 ip_rcv                                     0.0014
     1 ip_options_fragment                        0.0071
     1 ip_local_deliver                           0.0023
     1 ipfw_forward_check                         0.0139
     1 ip_forward                                 0.0011
     1 eth_header                                 0.0040
     1 .des_encrypt3_end                          0.0833
     1 des_decrypt3                               0.0034
     1 csum_partial_copy_generic                  0.0045
     1 call_out_firewall                          0.0125

Hope this data is helpful to someone... however the lack of visibility 
into the decrypt side makes things less clear

Speed with compression

Another user reported some results for connections with and without IP compression:

Subject: [Users] Speed with compression
   Date: Fri, 29 Jun 2001
   From: John McMonagle <johnm@advocap.org>

Did a couple tests with compression using the new 1.91 freeswan.

Running between 2 sites with cable modems.  Both  using approximately
130 mhz pentium.

Transferred files with ncftp.

Compressed file was a 6mb compressed  installation file.
Non compressed was 18mb /var/lib/rpm/packages.rpm

                            Compressed vpn          regular vpn
Compress file                42.59 kBs               42.08 kBs
regular file                110.84 kBs               41.66 kBs

Load  was about 0 either way.
Ping times were very similar  a bit above 9 ms.

Compression looks attractive to me.
Later in the same thread, project technical lead Henry Spencer added:
> is there a reason not to switch compression on?  I have large gateway boxes
> connecting 3 connections, one of them with a measly DS1 link...

Run some timing tests with and without, with data and loads representative
of what you expect in production.  That's the definitive way to decide. 
If compression is a net loss, then obviously, leave it turned off.  If it
doesn't make much difference, leave it off for simplicity and hence
robustness.  If there's a substantial gain, by all means turn it on. 

If both ends support compression and can successfully negotiate a
compressed connection (trivially true if both are FreeS/WAN 1.91), then
the crucial question is CPU cycles. 

Compression has some overhead, so one question is whether *your* data
compresses well enough to save you more CPU cycles (by reducing the volume
of data going through CPU-intensive encryption/decryption) than it costs
you.  Last time I ran such tests on data that was reasonably compressible
but not deliberately contrived to be so, this generally was not true --
compression cost extra CPU cycles -- so compression was worthwhile only if
the link, not the CPU, was the bottleneck.  However, that was before the
slow-compression bug was fixed.  I haven't had a chance to re-run those
tests yet, but it sounds like I'd probably see a different result. 
The bug he refers to was a problem with the compression libraries that had us using C code, rather than assembler, for compression. It was fixed before 1.91.

Methods of measuring

If you want to measure the loads FreeS/WAN puts on a system, note that tools such as top or measurements such as load average are more-or-less useless for this. They are not designed to measure something that does most of its work inside the kernel.

Here is a message from FreeS/WAN kernel programmer Richard Guy Briggs on this:

> I have a batch of boxes doing Freeswan stuff.
> I want to measure the CPU loading of the Freeswan tunnels, but am 
> having trouble seeing how I get some figures out...
> 
>  - Keying etc is in userspace so will show up on the per-process
>    and load average etc (ie pluto's load)

Correct.

>  - KLIPS is in the kernel space, and does not show up in load average
>    I think also that the KLIPS per-packet processing stuff is running
>    as part of an interrupt handler so it does not show up in the
>    /proc/stat system_cpu or even idle_cpu figures

It is not running in interrupt handler.  It is in the bottom half.
This is somewhere between user context (careful, this is not
userspace!) and hardware interrupt context.

> Is this correct, and is there any means of instrumenting how much the 
> cpu is being loaded - I don't like the idea of a system running out of 
> steam whilst still showing 100% idle CPU :-)

vmstat seems to do a fairly good job, but use a running tally to get a
good idea.  A one-off call to vmstat gives different numbers than a
running stat.  To do this, put an interval on your vmstat command
line.
and another suggestion from the same thread:
Subject: Re: Measuring the CPU usage of Freeswan
   Date: Mon, 29 Jan 2001
   From: Patrick Michael Kane <modus@pr.es.to>
 
The only truly accurate way to accurately track FreeSWAN CPU usage is to use
a CPU soaker. You run it on an unloaded system as a benchmark, then start up
FreeSWAN and take the difference to determine how much FreeSWAN is eating.
I believe someone has done this in the past, so you may find something in
the FreeSWAN archives.  If not, someone recently posted a URL to a CPU
soaker benchmark tool on linux-kernel.

Testing FreeS/WAN

This document discusses testing FreeS/WAN.

Not all types of testing are described here. Other parts of the documentation describe some tests:

installation document
testing for a successful install
configuration document
basic tests for a working configuration
web links document
General information on tests for interoperability between various IPsec implementations. This includes links to several test sites.
interoperation document.
More specific information on FreeS/WAN interoperation with other implementations.
performance document
performance measurements

The test setups and procedures described here can also be used in other testing, but this document focuses on testing the IPsec functionality of FreeS/WAN.

Testing opportunistic connections

This section teaches you how to test your opportunistically encrypted (OE) connections. To set up OE, please see the easy instructions in our quickstart guide.

Basic OE Test

This test is for basic OE functionality. For additional tests, keep reading.

Be sure IPsec is running. You can see whether it is with:

    ipsec setup status

If need be, you can restart it with:

    service ipsec restart

Load a FreeS/WAN test website from the host on which you're running FreeS/WAN. Note: the feds may be watching these sites. Type one of:

   links oetest.freeswan.org
   links oetest.freeswan.nl

A positive result looks like this:

   You  seem  to  be  connecting  from:  192.0.2.11 which DNS says is:
   gateway.example.com
     _________________________________________________________________
                                                                                
   Status E-route
   OE    enabled    16    192.139.46.73/32    ->    192.0.2.11/32   =>
   tun0x2097@192.0.2.11
   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
   tun0x208a@192.0.2.11

If you see this, congratulations! Your OE box will now encrypt its own traffic whenever it can. If you have difficulty, see our OE troubleshooting tips.

OE Gateway Test

If you've set up FreeS/WAN to protect a subnet behind your gateway, you'll need to run another simple test, which can be done from a machine running any OS. That's right, your Windows box can be protected by opportunistic encryption without any FreeS/WAN install or configuration on that box. From each protected subnet node , load the FreeS/WAN website with:

   links oetest.freeswan.org
   links oetest.freeswan.nl

A positive result looks like this:

   You  seem  to  be  connecting  from:  192.0.2.98 which DNS says is:
   box98.example.com
     _________________________________________________________________
                                                                                
   Status E-route
   OE    enabled    16    192.139.46.73/32    ->    192.0.2.98/32   =>
   tun0x134ed@192.0.2.11
   OE    enabled    176    192.139.46.77/32    ->   192.0.2.11/32   =>
   tun0x134d2@192.0.2.11

If you see this, congratulations! Your OE gateway will now encrypt traffic for this subnet node whenever it can. If you have difficulty, see our OE troubleshooting tips.

Additional OE tests

When testing OE, you will often find it useful to execute this command on the FreeS/WAN host:

   ipsec eroute

If you have established a connection (either for or for a subnet node) you will see a result like:

    192.0.2.11/32   -> 192.139.46.73/32  => tun0x149f@192.139.46.38

Key:

1.192.0.2.11/32Local start point of the protected traffic.
2.192.0.2.194/32Remote end point of the protected traffic.
3.192.0.48.38Remote FreeS/WAN node (gateway or host). May be the same as (2).
4.[not shown]Local FreeS/WAN node (gateway or host), where you've produced the output. May be the same as (1).

For extra assurance, you may wish to use a packet sniffer such as tcpdump to verify that packets are being encrypted. You should see output that indicates ESP encrypted data, for example:

    02:17:47.353750 PPPoE  [ses 0x1e12] IP 154: xy.example.com > oetest.freeswan.org: ESP(spi=0x87150d16,seq=0x55)

Testing with User Mode Linux

User Mode Linux allows you to run Linux as a user process on another Linux machine.

As of 1.92, the distribution has a new directory named testing. It contains a collection of test scripts and sample configurations. Using these, you can bring up several copies of Linux in user mode and have them build tunnels to each other. This lets you do some testing of a FreeS/WAN configuration on a single machine.

You need a moderately well-endowed machine for this to work well. Each UML wants about 16 megs of memory by default, which is plenty for FreeS/WAN usage. Typical regression testing only occasionally uses as many as 4 UMLs. If one is doing nothing else with the machine (in particular, not running X on it), then 128 megs and a 500MHz CPU are fine.

Documentation on these scripts is here. There is also documentation on automated testing here.

Configuration for a testbed network

A common test setup is to put a machine with dual Ethernet cards in between two gateways under test. You need at least five machines; two gateways, two clients and a testing machine in the middle.

The central machine both routes packets and provides a place to run diagnostic software for checking IPsec packets. See next section for discussion of using tcpdump(8) for this.

This makes things more complicated than if you just connected the two gateway machines directly to each other, but it also makes your test setup much more like the environment you actually use IPsec in. Those environments nearly always involve routing, and quite a few apparent IPsec failures turn out to be problems with routing or with firewalls dropping packets. This approach lets you deal with those problems on your test setup.

What you end up with looks like:

Testbed network

      subnet a.b.c.0/24
             |
      eth1 = a.b.c.1
         gate1
      eth0 = 192.168.p.1
             |
             |
      eth0 = 192.168.p.2
         route/monitor box
      eth1 = 192.168.q.2
             |
             |
      eth0 = 192.168.q.1
         gate2
      eth1 = x.y.z.1
              |
       subnet x.y.z.0/24
Where p and q are any convenient values that do not interfere with other
routes you may have. The ipsec.conf(5) file then has, among other things:
conn abc-xyz
      left=192.168.p.1
      leftnexthop=192.168.p.2
      right=192.168.q.1
      rightnexthop=192.168.q.2

Once that works, you can remove the "route/monitor box", and connect the two gateways to the Internet. The only parameters in ipsec.conf(5) that need to change are the four shown above. You replace them with values appropriate for your Internet connection, and change the eth0 IP addresses and the default routes on both gateways.

Note that nothing on either subnet needs to change. This lets you test most of your IPsec setup before connecting to the insecure Internet.

Using packet sniffers in testing

A number of tools are available for looking at packets. We will discuss using tcpdump(8), a common Linux tool included in most distributions. Alternatives offerring more-or-less the same functionality include:

Ethereal
Several people on our mailing list report a preference for this over tcpdump.
windump
a Windows version of tcpdump(8), possibly handy if you have Windows boxes in your network
Sniffit
A linux sniffer that we don't know much about. If you use it, please comment on our mailing list.

See also this index of packet sniffers.

tcpdump(8) may misbehave if run on the gateways themselves. It is designed to look into a normal IP stack and may become confused if you ask it to display data from a stack which has IPsec in play.

At one point, the problem was quite severe. Recent versions of tcpdump, however, understand IPsec well enough to be usable on a gateway. You can get the latest version from tcpdump.org.

Even with a recent tcpdump, some care is required. Here is part of a post from Henry on the topic:

> a) data from sunset to sunrise or the other way is not being
> encrypted (I am using tcpdump (ver. 3.4) -x/ping -p to check
> packages) 

What *interface* is tcpdump being applied to?  Use the -i option to
control this.  It matters!  If tcpdump is looking at the ipsecN
interfaces, e.g. ipsec0, then it is seeing the packets before they are
encrypted or after they are decrypted, so of course they don't look
encrypted.  You want to have tcpdump looking at the actual hardware
interfaces, e.g. eth0. 

Actually, the only way to be *sure* what you are sending on the wire is to
have a separate machine eavesdropping on the traffic.  Nothing you can do
on the machines actually running IPsec is 100% guaranteed reliable in this
area (although tcpdump is a lot better now than it used to be).

The most certain way to examine IPsec packets is to look at them on the wire. For security, you need to be certain, so we recommend doing that. To do so, you need a separate sniffer machine located between the two gateways. This machine can be routing IPsec packets, but it must not be an IPsec gateway. Network configuration for such testing is discussed above.

Here's another mailing list message with advice on using tcpdump(8):

Subject: RE: [Users] Encrypted???
   Date: Thu, 29 Nov 2001
   From: "Joe Patterson" <jpatterson@asgardgroup.com>

tcpdump -nl -i $EXT-IF proto 50

-nl tells it not to buffer output or resolve names (if you don't do that it
may confuse you by not outputing anything for a while), -i $EXT-IF (replace
with your external interface) tells it what interface to listen on, and
proto 50 is ESP.  Use "proto 51" if for some odd reason you're using AH, and
"udp port 500" if you want to see the isakmp key exchange/tunnel setup
packets.

You can also run `tcpdump -nl -i ipsec0` to see what traffic is on that
virtual interface.  Anything you see there *should* be either encrypted or
dropped (unless you've turned on some strange options in your ipsec.conf
file)

Another very handy thing is ethereal (http://www.ethereal.com/) which runs
on just about anything, has a nice gui interface (or a nice text-based
interface), and does a great job of protocol  breakdown.  For ESP and AH
it'll basically just tell you that there's a packet of that protocol, and
what the spi is, but for isakmp it'll actually show you a lot of the tunnel
setup information (until it gets to the point in the protocol where isakmp
is encrypted....)

Verifying encryption

The question of how to verify that messages are actually encrypted has been extensively discussed on the mailing list. See this thread.

If you just want to verify that packets are encrypted, look at them with a packet sniffer (see previous section ) located between the gateways. The packets should, except for some of the header information, be utterly unintelligible. The output of good encryption looks exactly like random noise.

A packet sniffer can only tell you that the data you looked at was encrypted. If you have stronger requirements -- for example if your security policy requires verification that plaintext is not leaked during startup or under various anomolous conditions -- then you will need to devise much more thorough tests. If you do that, please post any results or methodological details which your security policy allows you to make public.

You can put recognizable data into ping packets with something like:

        ping -p feedfacedeadbeef 11.0.1.1

"feedfacedeadbeef" is a legal hexadecimal pattern that is easy to pick out of hex dumps.

For other protocols, you may need to check if you have encrypted data or ASCII text. Encrypted data has approximately equal frequencies for all 256 possible characters. ASCII text has most characters in the printable range 0x20-0x7f, a few control characters less than 0x20, and none at all in the range 0x80-0xff. 0x20, space, is a good character to look for. In normal English text space occurs about once in seven characters, versus about once in 256 for random or encrypted data.

One thing to watch for: the output of good compression, like that of good encryption, looks just like random noise. You cannot tell just by looking at a data stream whether it has been compressed, encrypted, or both. You need a little care not to mistake compressed data for encrypted data in your testing.

Note also that weak encryption also produces random-looking output. You cannot tell whether the encryption is strong by looking at the output. To be sure of that, you would need to have both the algorithms and the implementation examined by experts.

For IPsec, you can get partial assurance from interoperability tests. See our interop document. When twenty products all claim to implement 3DES, and they all talk to each other, you can be fairly sure they have it right. Of course, you might wonder whether all the implementers are consipring to trick you or, more plausibly, whether some implementations might have "back doors" so they can get also it wrong when required.. If you're seriously worried about things like that, you need to get the code you use audited (good luck if it is not Open Source), or perhaps to talk to a psychiatrist about treatments for paranoia.

Mailing list pointers

Additional information on testing can be found in these mailing list messages:


Kernel configuration for FreeS/WAN

This section lists many of the options available when configuring a Linux kernel, and explains how they should be set on a FreeS/WAN IPsec gateway.

Not everyone needs to worry about kernel configuration

Note that in many cases you do not need to mess with these.

You may have a Linux distribution which comes with FreeS/WAN installed (see this list). In that case, you need not do a FreeS/WAN installation or a kernel configuration. Of course, you might still want to configure and rebuild your kernel to improve performance or security. This can be done with standard tools described in the Kernel HowTo.

If you need to install FreeS/WAN, then you do need to configure a kernel. However, you may choose to do that using the simplest procedure:

This document is for those who choose to configure their FreeS/WAN kernel themselves.

Assumptions and notation

Help text for most kernel options is included with the kernel files, and is accessible from within the configuration utilities. We assume you will refer to that, and to the Kernel HowTo, as necessary. This document covers only the FreeS/WAN-specific aspects of the problem.

To avoid duplication, this document section does not cover settings for the additional IPsec-related kernel options which become available after you have patched your kernel with FreeS/WAN patches. There is help text for those available from within the configuration utility.

We assume a common configuration in which the FreeS/WAN IPsec gateway is also doing ipchains(8) firewalling for a local network, and possibly masquerading as well.

Some suggestions below are labelled as appropriate for "a true paranoid". By this we mean they may cause inconvenience and it is not entirely clear they are necessary, but they appear to be the safest choice. Not using them might entail some risk. Of course one suggested mantra for security administrators is: "I know I'm paranoid. I wonder if I'm paranoid enough."

Labels used

Six labels are used to indicate how options should be set. We mark the labels with [square brackets]. For two of these labels, you have no choice:

[required]
essential for FreeS/WAN operation.
[incompatible]
incompatible with FreeS/WAN.

those must be set correctly or FreeS/WAN will not work

FreeS/WAN should work with any settings of the others, though of course not all combinations have been tested. We do label these in various ways, but these labels are only suggestions.

[recommended]
useful on most FreeS/WAN gateways
[disable]
an unwelcome complication on a FreeS/WAN gateway.
[optional]
Your choice. We outline issues you might consider.
[anything]
This option has no direct effect on FreeS/WAN and related tools, so you should be able to set it as you please.

Of course complexity is an enemy in any effort to build secure systems. For maximum security, any feature that can reasonably be turned off should be. "If in doubt, leave it out."

Kernel options for FreeS/WAN

Indentation is based on the nesting shown by 'make menuconfig' with a 2.2.16 kernel for the i386 architecture.

Code maturity and level options
Prompt for development ... code/drivers
[optional] If this is no, experimental drivers are not shown in later menus.

For most FreeS/WAN work, no is the preferred setting. Using new or untested components is too risky for a security gateway.

However, for some hardware (such as the author's network cards) the only drivers available are marked new/experimental. In such cases, you must enable this option or your cards will not appear under "network device support". A true paranoid would leave this option off and replace the cards.

Processor type and features
[anything]
Loadable module support
Enable loadable module support
[optional] A true paranoid would disable this. An attacker who has root access to your machine can fairly easily install a bogus module that does awful things, provided modules are enabled. A common tool for attackers is a "rootkit", a set of tools the attacker uses once he or she has become root on your system. The kit introduces assorted additional compromises so that the attacker will continue to "own" your system despite most things you might do to recovery the situation. For Linux, there is a tool called knark which is basically a rootkit packaged as a kernel module.

With modules disabled, an attacker cannot install a bogus module. The only way he can achieve the same effects is to install a new kernel and reboot. This is considerably more likely to be noticed.

Many FreeS/WAN gateways run with modules enabled. This simplifies some administrative tasks and some ipchains features are available only as modules. Once an enemy has root on your machine your security is nil, so arguably defenses which come into play only in that situation are pointless.

Set version information ....
[optional] This provides a check to prevent loading modules compiled for a different kernel.
Kernel module loader
[disable] It gives little benefit on a typical FreeS/WAN gate and entails some risk.
General setup
We list here only the options that matter for FreeS/WAN.
Networking support
[required]
Sysctl interface
[optional] If this option is turned on and the /proc filesystem installed, then you can control various system behaviours by writing to files under /proc/sys. For example:
        echo 1 > /proc/sys/net/ipv4/ipforward
turns IP forwarding on.

Disabling this option breaks many firewall scripts. A true paranoid would disable it anyway since it might conceivably be of use to an attacker.

Plug and Play support
[anything]
Block devices
[anything]
Networking options
Packet socket
[optional] This kernel feature supports tools such as tcpdump(8) which communicate directly with network hardware, bypassing kernel protocols. This is very much a two-edged sword:
  • such tools can be very useful to the firewall admin, especially during initial testing
  • should an evildoer breach your firewall, such tools could give him or her a great deal of information about the rest of your network
We recommend disabling this option on production gateways.
Kernel/User netlink socket
[optional] Required if you want to use advanced router features.
Routing messages
[optional]
Netlink device emulation
[optional]
Network firewalls
[recommended] You need this if the IPsec gateway also functions as a firewall.

Even if the IPsec gateway is not your primary firewall, we suggest setting this so that you can protect the gateway with at least basic local packet filters.

Socket filtering
[disable] This enables an older filtering interface. We suggest using ipchains(8) instead. To do that, set the "Network firewalls" option just above, and not this one.
Unix domain sockets
[required] These sockets are used for communication between the ipsec(8) commands and the ipsec_pluto(8) daemon.
TCP/IP networking
[required]
IP: multicasting
[anything]
IP: advanced router
[optional] This gives you policy routing, which some people have used to good advantage in their scripts for FreeS/WAN gateway management. It is not used in our distributed scripts, so not required unless you want it for custom scripts. It requires the netlink interface between kernel code and the iproute2(8) command.
IP: kernel level autoconfiguration
[disable] It gives little benefit on a typical FreeS/WAN gate and entails some risk.
IP: firewall packet netlink device
[disable]
IP: transparent proxy support
[optional] This is required in some firewall configurations, but should be disabled unless you have a definite need for it.
IP: masquerading
[optional] Required if you want to use non-routable private IP addresses for your local network.
IP: Optimize as router not host
[recommended]
IP: tunneling
[required]
IP: GRE tunnels over IP
[anything]
IP: aliasing support
[anything]
IP: ARP daemon support (EXPERIMENTAL)
Not required on most systems, but might prove useful on heavily-loaded gateways.
IP: TCP syncookie support
[recommended] It provides a defense against a denial of service attack which uses bogus TCP connection requests to waste resources on the victim machine.
IP: Reverse ARP
IP: large window support
[recommended] unless you have less than 16 meg RAM
IPv6
[optional] FreeS/WAN does not currently support IPv6, though work on integrating FreeS/WAN with the Linux IPv6 stack has begun. Details.

It should be possible to use IPv4 FreeS/WAN on a machine which also does IPv6. This combination is not yet well tested. We would be quite interested in hearing results from anyone expermenting with it, via the mailing list.

We do not recommend using IPv6 on production FreeS/WAN gateways until more testing has been done.

Novell IPX
[disable]
Appletalk
[disable] Quite a few Linux installations use IP but also have some other protocol, such as Appletalk or IPX, for communication with local desktop machines. In theory it should be possible to configure IPsec for the IP side of things without interfering with the second protocol.

We do not recommend this. Keep the software on your gateway as simple as possible. If you need a Linux-based Appletalk or IPX server, use a separate machine.

Telephony support
[anything]
SCSI support
[anything]
I2O device support
[anything]
Network device support
[anything] should work, but there are some points to note.

The development team test almost entirely on 10 or 100 megabit Ethernet and modems. In principle, any device that can do IP should be just fine for IPsec, but in the real world any device that has not been well-tested is somewhat risky. By all means try it, but don't bet your project on it until you have solid test results.

If you disabled experimental drivers in the Code maturity section above, then those drivers will not be shown here. Check that option before going off to hunt for missing drivers.

If you want Linux to automatically find more than one ethernet interface at boot time, you need to:

  • compile the appropriate driver(s) into your kernel. Modules will not work for this
  • add a line such as
       append="ether=0,0,eth0 ether=0,0,eth1"
    
    to your /etc/lilo.conf file. In some cases you may need to specify parameters such as IRQ or base address. The example uses "0,0" for these, which tells the system to search. If the search does not succeed on your hardware, then you should retry with explicit parameters. See the lilo.conf(5) man page for details.
  • run lilo(8)
Having Linux find the cards this way is not necessary, but is usually more convenient than loading modules in your boot scripts.
Amateur radio support
[anything]
IrDA (infrared) support
[anything]
ISDN subsystem
[anything]
Old CDROM drivers
[anything]
Character devices
The only required character device is:
random(4)
[required] This is a source of random numbers which are required for many cryptographic protocols, including several used in IPsec.

If you are comfortable with C source code, it is likely a good idea to go in and adjust the #define lines in /usr/src/linux/drivers/char/random.c to ensure that all sources of randomness are enabled. Relying solely on keyboard and mouse randomness is dubious procedure for a gateway machine. You could also increase the randomness pool size from the default 512 bytes (128 32-bit words).

Filesystems
[anything] should work, but we suggest limiting a gateway machine to the standard Linux ext2 filesystem in most cases.
Network filesystems
[disable] These systems are an unnecessary risk on an IPsec gateway.
Console drivers
[anything]
Sound
[anything] should work, but we suggest enabling sound only if you plan to use audible alarms for firewall problems.
Kernel hacking
[disable] This might be enabled on test machines, but should not be on production gateways.

Other configuration possibilities

This document describes various options for FreeS/WAN configuration which are less used or more complex (often both) than the standard cases described in our config and quickstart documents.

Some rules of thumb about configuration

Tunnels are cheap

Nearly all of the overhead in IPsec processing is in the encryption and authentication of packets. Our performance document discusses these overheads.

Beside those overheads, the cost of managing additional tunnels is trivial. Whether your gateway supports one tunnel or ten just does not matter. A hundred might be a problem; there is a section on this in the performance document.

So, in nearly all cases, if using multiple tunnels gives you a reasonable way to describe what you need to do, you should describe it that way in your configuration files.

For example, one user recently asked on a mailing list about this network configuration:

        netA---gwA---gwB---netB
                            |----netC

   netA and B are secured netC not.
   netA and gwA can not access netC

The user had constructed only one tunnel, netA to netB, and wanted to know how to use ip-route to get netC packets into it. This is entirely unnecessary. One of the replies was:

  The simplest way and indeed the right way to
  solve this problem is to set up two connections:

        leftsubnet=NetA
        left=gwA
        right=gwB
        rightsubnet=NetB
  and
        leftsubnet=NetA
        left=gwA
        right=gwB
        rightsubnet=NetC

This would still be correct even if we added nets D, E, F, ... to the above diagram and needed twenty tunnels.

Of course another possibility would be to just use one tunnel, with a subnet mask that includes both netB and netC (or B, C, D, ...). See next section.

In general, you can construct as many tunnels as you need. Networks like netC in this example that do not connect directly to the gateway are fine, as long as the gateway can route to them.

The number of tunnels can become an issue if it reaches 50 or so. This is discussed in the performance document. Look there for information on supporting hundreds of Road Warriors from one gateway.

If you find yourself with too many tunnels for some reason like having eight subnets at one location and nine at another so you end up with 9*8=72 tunnels, read the next section here.

Subnet sizes

The subnets used in leftsubnet and rightsubnet can be of any size that fits your needs, and they need not correspond to physical networks.

You adjust the size by changing the subnet mask , the number after the slash in the subnet description. For example

As an example of using these in connection descriptions, suppose your company's head office has four physical networks using the address ranges:

192.168.100.0/24
development
192.168.101.0/24
production
192.168.102.0/24
marketing
192.168.103.0/24
administration

You can use exactly those subnets in your connection descriptions, or use larger subnets to grant broad access if required:

leftsubnet=192.168.100.0/24
remote hosts can access only development
leftsubnet=192.168.100.0/23
remote hosts can access development or production
leftsubnet=192.168.102.0/23
remote hosts can access marketing or administration
leftsubnet=192.168.100.0/22
remote hosts can access any of the four departments

or use smaller subnets to restrict access:

leftsubnet=192.168.103.0/24
remote hosts can access any machine in administration
leftsubnet=192.168.103.64/28
remote hosts can access only certain machines in administration.
leftsubnet=192.168.103.42/32
remote hosts can access only one particular machine in administration

To be exact, 192.68.103.64/28 means all addresses whose top 28 bits match 192.168.103.64. There are 16 of these because there are 16 possibilities for the remainingg 4 bits. Their addresses are 192.168.103.64 to 192.168.103.79.

Each connection description can use a different subnet if required.

It is possible to use all the examples above on the same FreeS/WAN gateway, each in a different connection description, perhaps for different classes of user or for different remote offices.

It is also possible to have multiple tunnels using different leftsubnet descriptions with the same right. For example, when the marketing manager is on the road he or she might have access to:

leftsubnet=192.168.102.0/24
all machines in marketing
192.168.101.32/29
some machines in production
leftsubnet=192.168.103.42/32
one particular machine in administration

This takes three tunnels, but tunnels are cheap. If the laptop is set up to build all three tunnels automatically, then he or she can access all these machines concurrently, perhaps from different windows.

Other network layouts

Here is the usual network picture for a site-to-site VPN::

     Sunset==========West------------------East=========Sunrise
           local net       untrusted net       local net

and for the Road Warrior::

                                           telecommuter's PC or
                                           traveller's laptop
     Sunset==========West------------------East
         corporate LAN     untrusted net

Other configurations are also possible.

The Internet as a big subnet

A telecommuter might have:

     Sunset==========West------------------East ================= firewall --- the Internet
         home network      untrusted net        corporate network

This can be described as a special case of the general subnet-to-subnet connection. The subnet on the right is 0.0.0.0/0, the whole Internet.

West (the home gateway) can have its firewall rules set up so that only IPsec packets to East are allowed out. It will then behave as if its only connection to the world was a wire to East.

When machines on the home network need to reach the Internet, they do so via the tunnel, East and the corporate firewall. From the viewpoint of the Internet (perhaps of some EvilDoer trying to break in!), those home office machines are behind the firewall and protected by it.

Wireless

Another possible configuration comes up when you do not trust the local network, either because you have very high security standards or because your are using easily-intercepted wireless signals.

Some wireless networks have built-in encryption called WEP, but its security is dubious. It is a fairly common practice to use IPsec instead.

In this case, part of your network may look like this:

          West-----------------------------East == the rest of your network
     workstation   untrusted wireless net

Of course, there would likely be several wireless workstations, each with its own IPsec tunnel to the East gateway.

The connection descriptions look much like Road Warrior descriptions:

The rightsubnet= parameter might be set in any of several ways:

rightsubnet=0.0.0.0/0
allowing workstations to access the entire Internet (see above)
rightsubnet=a.b.c.0/24
allowing access to your entire local network
rightsubnet=a.b.c.d/32
restricting the workstation to connecting to a particular server

Of course you can mix and match these as required. For example, a university might allow faculty full Internet access while letting student laptops connect only to a group of lab machines.

Choosing connection types

One choice you need to make before configuring additional connections is what type or types of connections you will use. There are several options, and you can use more than one concurrently.

Manual vs. automatic keying

IPsec allows two types of connections, with manual or automatic keying. FreeS/WAN starts them with commands such as:

        ipsec manual --up name
        ipsec auto --up name

The difference is in how they are keyed.

Manually keyed connections
use keys stored in ipsec.conf .
Automatically keyed connections
use keys automatically generated by the Pluto key negotiation daemon. The key negotiation protocol, IKE, must authenticate the other system. (It is vulnerable to a man-in-the-middle attack if used without authentication.) We currently support two authentication methods:

A third method, using RSA keys embedded in X.509 certtificates, is provided by user patches.

Manually keyed connections provide weaker security than automatically keyed connections. An opponent who reads ipsec.secrets(5) gets your encryption key and can read all data encrypted by it. If he or she has an archive of old messages, all of them back to your last key change are also readable.

With automatically-(re)-keyed connections, an opponent who reads ipsec.secrets(5) gets the key used to authenticate your system in IKE -- the shared secret or your private key, depending what authentication mechanism is in use. However, he or she does not automatically gain access to any encryption keys or any data.

An attacker who has your authentication key can mount a man-in-the-middle attack and, if that succeeds, he or she will get encryption keys and data. This is a serious danger, but it is better than having the attacker read everyting as soon as he or she breaks into ipsec.secrets(5).. Moreover, the keys change often so an opponent who gets one key does not get a large amount of data. To read all your data, he or she would have to do a man-in-the-middle attack at every key change.

We discuss using manual keying in production below, but this is not recommended except in special circumstances, such as needing to communicate with some implementation that offers no auto-keyed mode compatible with FreeS/WAN.

Manual keying may also be useful for testing. There is some discussion of this in our FAQ.

Authentication methods for auto-keying

The IKE protocol which Pluto uses to negotiate connections between gateways must use some form of authentication of peers. A gateway must know who it is talking to before it can create a secure connection. We support two basic methods for this authentication:

There are, howver, several variations on the RSA theme, using different methods of managing the RSA keys:

Public keys in ipsec.conf(5 ) give a reasonably straightforward method of specifying keys for explicitly configured connections.

Putting public keys in DNS allows us to support opportunistic encryption. Any two FreeS/WAN gateways can provide secure communication, without either of them having any preset information about the other.

X.509 certificates may be required to interface to various PKIs.

Advantages of public key methods

Authentication with a public key method such as RSA has some important advantages over using shared secrets.

There is also a disadvantage:

This is partly counterbalanced by the fact that the key is never transmitted and remains under your control at all times. It is likely necessary, however, to take account of this in setting security policy. For example, you should change gateway keys when an administrator leaves the company, and should change them periodically in any case.

Overall, public key methods are more secure, more easily managed and more flexible. We recommend that they be used for all connections, unless there is a compelling reason to do otherwise.

Using shared secrets in production

Generally, public key methods are preferred for reasons given above, but shared secrets can be used with no loss of security, just more work and perhaps more need to take precautions.

What I call "shared secrets" are sometimes also called "pre-shared keys". They are used only for for authentication, never for encryption. Calling them "pre-shared keys" has confused some users into thinking they were encryption keys, so I prefer to avoid the term..

If you are interoperating with another IPsec implementation, you may find its documentation calling them "passphrases".

Putting secrets in ipsec.secrets(5)

If shared secrets are to be used to authenticate communication for the Diffie-Hellman key exchange in the IKE protocol, then those secrets must be stored in /etc/ipsec.secrets. For details, see the ipsec.secrets(5) man page.

A few considerations are vital:

Each line has the IP addresses of the two gateways plus the secret. It should look something like this:

        10.0.0.1 11.0.0.1 : PSK "jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT"

PSK indicates the use of a pre-s hared key. The quotes and the whitespace shown are required.

You can use any character string as your secret. For security, it should be both long and extremely hard to guess. We provide a utility to generate such strings, ipsec_ranbits(8).

You want the same secret on the two gateways used, so you create a line with that secret and the two gateway IP addresses. The installation process supplies an example secret, useful only for testing. You must change it for production use.

File security

You must deliver this file, or the relevant part of it, to the other gateway machine by some secure means. Don't just FTP or mail the file! It is vital that the secrets in it remain secret. An attacker who knew those could easily have all the data on your "secure" connection.

This file must be owned by root and should have permissions rw-------.

Shared secrets for road warriors

You can use a shared secret to support a single road warrior connecting to your gateway, and this is a reasonable thing to do in some circumstances. Public key methods have advantages, discussed above, but they are not critical in this case.

To do this, the line in ipsec.secrets(5) is something like:

        10.0.0.1 0.0.0.0 : PSK "jxTR1lnmSjuj33n4W51uW3kTR55luUmSmnlRUuWnkjRj3UuTV4T3USSu23Uk55nWu5TkTUnjT"
where the 0.0.0.0 means that any IP address is acceptable.

For more than one road warrior, shared secrets are not recommended. If shared secrets are used, then when the responder needs to look up the secret, all it knows about the sender is an IP address. This is fine if the sender is at a fixed IP address specified in the config file. It is also fine if only one road warrior uses the wildcard 0.0.0.0 address. However, if you have more than one road warrior using shared secret authentication, then they must all use that wildcard and therefore all road warriors using PSK autentication must use the same secret. Obviously, this is insecure.

For multiple road warriors, use public key authentication. Each roadwarrior can then have its own identity (our leftid= or rightid= parameters), its own public/private key pair, and its own secure connection.

Using manual keying in production

Generally, automatic keying is preferred over manual keying for production use because it is both easier to manage and more secure. Automatic keying frees the admin from much of the burden of managing keys securely, and can provide perfect forward secrecy. This is discussed in more detail above.

However, it is possible to use manual keying in production if that is what you want to do. This might be necessary, for example, in order to interoperate with some device that either does not provide automatic keying or provides it in some version we cannot talk to.

Note that with manual keying all security rests with the keys . If an adversary acquires your keys, you've had it. He or she can read everything ever sent with those keys, including old messages he or she may have archived.

You need to be really paranoid about keys if you're going to rely on manual keying for anything important.

Linux FreeS/WAN provides some facilities to help with this. In particular, it is good policy to keep keys in separate files so you can edit configuration information in /etc/ipsec.conf without exposing keys to "shoulder surfers" or network snoops. We support this with the also= and include syntax in ipsec.conf(5).

See the last example in our examples file. In the /etc/ipsec.conf conn samplesep section, it has the line:

        also=samplesep-keys

which tells the "ipsec manual" script to insert the configuration description labelled "samplesep-keys" if it can find it. The /etc/ipsec.conf file must also have a line such as:

include ipsec.*.conf

which tells it to read other files. One of those other files then might contain the additional data:

conn samplesep-keys
  spi=0x200
  esp=3des-md5-96
  espenckey=0x01234567_89abcdef_02468ace_13579bdf_12345678_9abcdef0
  espauthkey=0x12345678_9abcdef0_2468ace0_13579bdf

The first line matches the label in the "also=" line, so the indented lines are inserted. The net effect is exactly as if the inserted lines had occurred in the original file in place of the "also=" line.

Variables set here are:

spi
A number needed by the manual keying code. Any 3-digit hex number will do, but if you have more than one manual connection then spi must be different for each connection.
esp
Options for ESP (Encapsulated Security Payload), the usual IPsec encryption mode. Settings here are for encryption using triple DES and authentication using MD5. Note that encryption without authentication should not be used; it is insecure.
espenkey
Key for ESP encryption. Here, a 192-bit hex number for triple DES.
espauthkey
Key for ESP authentication. Here, a 128-bit hex number for MD5.

Note that the example keys we supply are intended only for testing. For real use, you should go to automatic keying. If that is not possible, create your own keys for manual mode and keep them secret

Of course, any files containing keys must have 600 permissions and be owned by root.

If you connect in this way to multiple sites, we recommend that you keep keys for each site in a separate file and adopt some naming convention that lets you pick them all up with a single "include" line. This minimizes the risk of losing several keys to one error or attack and of accidentally giving another site admin keys which he or she has no business knowing.

Also note that if you have multiple manually keyed connections on a single machine, then the spi parameter must be different for each one. Any 3-digit hex number is OK, provided they are different for each connection. We reserve the range 0x100 to 0xfff for manual connections. Pluto assigns SPIs from 0x1000 up for automatically keyed connections.

If ipsec.conf(5) contains keys for manual mode connections, then it too must have permissions rw-------. We recommend instead that, if you must manual keying in production, you keep the keys in separate files.

Note also that ipsec.conf is installed with permissions rw-r--r--. If you plan to use manually keyed connections for anything more than initial testing, you must:

We recommend the latter method for all but the simplest configurations.

Creating keys with ranbits

You can create new random keys with the ranbits(8) utility. For example, the commands:

      umask 177
      ipsec ranbits 192  > temp
      ipsec ranbits 128 >> temp

create keys in the sizes needed for our default algorithms:

If you want to use SHA instead of MD5, that requires a 160-bit key

Note that any temporary files used must be kept secure since they contain keys. That is the reason for the umask command above. The temporary file should be deleted as soon as you are done with it. You may also want to change the umask back to its default value after you are finished working on keys.

The ranbits utility may pause for a few seconds if not enough entropy is available immediately. See ipsec_ranbits(8) and random(4) for details. You may wish to provide some activity to feed entropy into the system. For example, you might move the mouse around, type random characters, or do du /usr > /dev/null in the background.

Setting up connections at boot time

You can tell the system to set up connections automatically at boot time by putting suitable stuff in /etc/ipsec.conf on both systems. The relevant section of the file is labelled by a line reading config setup.

Details can be found in the ipsec.conf(5) man page. We also provide a file of example configurations.

The most likely options are something like:

interfaces="ipsec0=eth0 ipsec1=ppp0"
Tells KLIPS which interfaces to use. Up to four interfaces numbered ipsec[0-3] are supported. Each interface can support an arbitrary number of tunnels.

Note that for PPP, you give the ppp[0-9] device name here, not the underlying device such as modem (or eth1 if you are using PPPoE).

interfaces=%defaultroute
Alternative setting, useful in simple cases. KLIPS will pick up both its interface and the next hop information from the settings of the Linux default route.
forwardcontrol=no
Normally "no". Set to "yes" if the IP forwarding option is disabled in your network configuration. (This can be set as a kernel configuration option or later. e.g. on Redhat, it's in /etc/sysconfig/network and on SuSE you can adjust it with Yast.) Linux FreeS/WAN will then enable forwarding when starting up and turn it off when going down. This is used to ensure that no packets will be forwarded before IPsec comes up and takes control.
syslog=daemon.error
Used in messages to the system logging daemon (syslogd) to specify what type of software is sending the messages. If the settings are "daemon.error" as in our example, then syslogd treats the messages as error messages from a daemon.

Note that Pluto does not currently pay attention to this variable. The variable controls setup messages only.

klipsdebug=
Debug settings for KLIPS.
plutodebug=
Debug settings for Pluto.
... for both the above DEBUG settings
Normally, leave empty as shown above for no debugging output.
Use "all" for maximum information.
See ipsec_klipsdebug(8) and ipsec_pluto(8) man page for other options. Beware that if you set /etc/ipsec.conf to enable debug output, your system's log files may get large quickly.
dumpdir=/safe/directory
Normally, programs started by ipsec setup don't crash. If they do, by default, no core dump will be produced because such dumps would contain secrets. If you find you need to debug such crashes, you can set dumpdir to the name of a directory in which to collect the core file.
manualstart=
List of manually keyed connections to be automatically started at boot time. Useful for testing, but not for long term use. Connections which are automatically started should also be automatically re-keyed.
pluto=yes
Whether to start Pluto when ipsec startup is done.
This parameter is optional and defaults to "yes" if not present.

"yes" is strongly recommended for production use so that the keying daemon (Pluto) will automatically re-key the connections regularly. The ipsec-auto parameters ikelifetime, ipseclifetime and reykeywindow give you control over frequency of rekeying.

plutoload="reno-van reno-adam reno-nyc"
List of tunnels (by name, e.g. fred-susan or reno-van in our examples) to be loaded into Pluto's internal database at startup. In this example, Pluto loads three tunnels into its database when it is started.

If plutoload is "%search", Pluto will load any connections whose description includes "auto=add" or "auto=start".

plutostart="reno-van reno-adam reno-nyc"
List of tunnels to attempt to negotiate when Pluto is started.

If plutostart is "%search", Pluto will start any connections whose description includes "auto=start".

Note that, for a connection intended to be permanent, both gateways should be set try to start the tunnel. This allows quick recovery if either gateway is rebooted or has its IPsec restarted. If only one gateway is set to start the tunnel and the other gateway restarts, the tunnel may not be rebuilt.

plutowait=no
Controls whether Pluto waits for one tunnel to be established before starting to negotiate the next. You might set this to "yes"
  • if your gateway is a very limited machine and you need to conserve resources.
  • for debugging; the logs are clearer if only one connection is brought up at a time
For a busy and resource-laden production gateway, you likely want "no" so that connections are brought up in parallel and the whole process takes less time.

The example assumes you are at the Reno office and will use IPsec to Vancouver, New York City and Amsterdam.

Multiple tunnels between the same two gateways

Consider a pair of subnets, each with a security gateway, connected via the Internet:

         192.168.100.0/24           left subnet
              |
         192.168.100.1
         North Gateway
         101.101.101.101            left
              |
         101.101.101.1              left next hop
         [Internet]
         202.202.202.1              right next hop
              |
         202.202.202.202            right
         South gateway
         192.168.200.1
              |
         192.168.200.0/24           right subnet

A tunnel specification such as:

conn northnet-southnet
      left=101.101.101.101
      leftnexthop=101.101.101.1
      leftsubnet=192.168.100.0/24
      leftfirewall=yes
      right=202.202.202.202
      rightnexthop=202.202.202.1
      rightsubnet=192.168.200.0/24
      rightfirewall=yes
will allow machines on the two subnets to talk to each other. You might test this by pinging from polarbear (192.168.100.7) to penguin (192.168.200.5).

However, this does not cover other traffic you might want to secure. To handle all the possibilities, you might also want these connection descriptions:

conn northgate-southnet
      left=101.101.101.101
      leftnexthop=101.101.101.1
      right=202.202.202.202
      rightnexthop=202.202.202.1
      rightsubnet=192.168.200.0/24
      rightfirewall=yes

conn northnet-southgate
      left=101.101.101.101
      leftnexthop=101.101.101.1
      leftsubnet=192.168.100.0/24
      leftfirewall=yes
      right=202.202.202.202
      rightnexthop=202.202.202.1

Without these, neither gateway can do IPsec to the remote subnet. There is no IPsec tunnel or eroute set up for the traffic.

In our example, with the non-routable 192.168.* addresses used, packets would simply be discarded. In a different configuration, with routable addresses for the remote subnet, they would be sent unencrypted since there would be no IPsec eroute and there would be a normal IP route.

You might also want:

conn northgate-southgate
      left=101.101.101.101
      leftnexthop=101.101.101.1
      right=202.202.202.202
      rightnexthop=202.202.202.1

This is required if you want the two gateways to speak IPsec to each other.

This requires a lot of duplication of details. Judicious use of also= and include can reduce this problem.

Note that, while FreeS/WAN supports all four tunnel types, not all implementations do. In particular, some versions of Windows 2000 and the freely downloadable version of PGP provide only "client" functionality. You cannot use them as gateways with a subnet behind them. To get that functionality, you must upgrade to Windows 2000 server or the commercially available PGP products.

One tunnel plus advanced routing

It is also possible to use the new routing features in 2.2 and later kernels to avoid most needs for multple tunnels. Here is one mailing list message on the topic:
Subject: Re: linux-ipsec: IPSec packets not entering tunnel?
   Date: Mon, 20 Nov 2000
   From: Justin Guyett <jfg@sonicity.com>

On Mon, 20 Nov 2000, Claudia Schmeing wrote:

> Right                                                         Left
>                      "home"                "office"
> 10.92.10.0/24 ---- 24.93.85.110 ========= 216.175.164.91 ---- 10.91.10.24/24
>
> I've created all four tunnels, and can ping to test each of them,
> *except* homegate-officenet.

I keep wondering why people create all four tunnels.  Why not route
traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?
And 99% of the time you don't need to access "office" directly, which
means you can eliminate all but the subnet<->subnet connection.
and FreeS/WAN technical lead Henry Spencer's comment:
> I keep wondering why people create all four tunnels.  Why not route
> traffic generated from home to 10.91.10.24/24 out ipsec0 with iproute2?

This is feasible, given some iproute2 attention to source addresses, but
it isn't something we've documented yet... (partly because we're still
making some attempt to support 2.0.xx kernels, which can't do this, but
mostly because we haven't caught up with it yet).

> And 99% of the time you don't need to access "office" directly, which
> means you can eliminate all but the subnet<->subnet connection.

Correct in principle, but people will keep trying to ping to or from the
gateways during testing, and sometimes they want to run services on the
gateway machines too.

An Opportunistic Gateway

Start from full opportunism

Full opportunism allows you to initiate and receive opportunistic connections on your machine. The remaining instructions in this section assume you have first set up full opportunism on your gateway using these instructions. Both sets of instructions require mailing DNS records to your ISP. Collect DNS records for both the gateway (above) and the subnet nodes (below) before contacting your ISP.

Reverse DNS TXT records for each protected machine

You need these so that your Opportunistic peers can:

On the gateway, generate a TXT record with:

    ipsec showhostkey --txt 192.0.2.11

Use your gateway address in place of 192.0.2.11.

You should see (keys are trimmed for clarity throughout our example):

    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"

This MUST BE the same key as in your gateway's TXT record, or nothing will work.

In a text file, make one copy of this TXT record for each subnet node:

    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"
                                                                                
    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"
                                                                                
    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"

Above each entry, insert a line like this:

    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.

It must include:

The result will be a file of TXT records, like this:

    98.2.0.192.in-addr.arpa. IN PTR arthur.example.com.
    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"
                                                                                
    99.2.0.192.in-addr.arpa. IN PTR ford.example.com.
    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"
                                                                                
    100.2.0.192.in-addr.arpa. IN PTR trillian.example.com.
    ; RSA 2048 bits  gateway.example.com   Sat Apr 15 13:53:22 2000
    IN TXT  "X-IPsec-Server(10)=192.0.2.11" " AQOF8tZ2...+buFuFn/"

Publish your records

Ask your ISP to publish all the reverse DNS records you have collected. There may be a delay of up to 48 hours as the records propagate.

...and test them

Check a couple of records with commands like this one:

    ipsec verify --host ford.example.com
    ipsec verify --host trillian.example.com

The verify command checks for TXT records for both the subnet host and its gateway. You should see output like:

    ...
    Looking for TXT in reverse map: 99.2.0.192.in-addr.arpa [OK]
    ...
    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
    ...
    Looking for TXT in reverse map: 100.2.0.192.in-addr.arpa [OK]
    ...
    Looking for TXT in reverse map: 11.2.0.192.in-addr.arpa   [OK]
    ...

No Configuration Needed

FreeS/WAN 2.x ships with a built-in, automatically enabled OE connection conn packetdefault which applies OE, if possible, to all outbound traffic routed through the FreeS/WAN box. The ipsec.conf(5) manual describes this connection in detail. While the effect is much the same as private-or-clear, the implementation is different: notably, it does not use policy groups.

You can create more complex OE configurations for traffic forwarded through a FreeS/WAN box, as explained in our policy groups document, or disable OE using these instructions.

Extruded Subnets

What we call extruded subnets are a special case of VPNs.

If your buddy has some unused IP addresses, in his subnet far off at the other side of the Internet, he can loan them to you... provided that the connection between you and him is fast enough to carry all the traffic between your machines and the rest of the Internet. In effect, he "extrudes" a part of his address space over the network to you, with your Internet traffic appearing to originate from behind his Internet gateway.

As far as the Internet is concerned, your new extruded net is behind your buddy's gateway. You route all your packets for the Internet at large out his gateway, and receive return packets the same way. You route your local packets locally.

Suppose your friend has a.b.c.0/24 and wants to give you a.b.c.240/28. The initial situation is:

    subnet           gateway          Internet
  a.b.c.0/24    a.b.c.1    p.q.r.s
where anything from the Internet destined for any machine in a.b.c.0/24 is routed via p.q.r.s and that gateway knows what to do from there.

Of course it is quite normal for various smaller subnets to exist behind your friend's gateway. For example, your friend's company might have a.b.c.16/28=development, a.b.c.32/28=marketing and so on. The Internet neither knows not cares about this; it just delivers packets to the p.q.r.s and lets the gateway do whatever needs to be done from there.

What we want to do is take a subnet, perhaps a.b.c.240/28, out of your friend's physical location while still having your friend's gateway route to it. As far as the Internet is concerned, you remain behind that gateway.

    subnet           gateway          Internet       your gate  extruded

  a.b.c.0/24   a.b.c.1     p.q.r.s              d.e.f.g         a.b.c.240/28                

                           ========== tunnel ==========

The extruded addresses have to be a complete subnet.

In our example, the friend's security gateway is also his Internet gateway, but this is not necessary. As long as all traffic from the Internet to his addresses passes through the Internet gate, the security gate could be a machine behind that. The IG would need to route all traffic for the extruded subnet to the SG, and the SG could handle the rest.

First, configure your subnet using the extruded addresses. Your security gateway's interface to your subnet needs to have an extruded address (possibly using a Linux virtual interface , if it also has to have a different address). Your gateway needs to have a route to the extruded subnet, pointing to that interface. The other machines at your site need to have addresses in that subnet, and default routes pointing to your gateway.

If any of your friend's machines need to talk to the extruded subnet, they need to have a route for the extruded subnet, pointing at his gateway.

Then set up an IPsec subnet-to-subnet tunnel between your gateway and his, with your subnet specified as the extruded subnet, and his subnet specified as "0.0.0.0/0".

The tunnel description should be:

conn extruded
        left=p.q.r.s
        leftsubnet=0.0.0.0/0
        right=d.e.f.g
        rightsubnet=a.b.c.0/28

If either side was doing firewalling for the extruded subnet before the IPsec connection is set up, you'll need to poke holes in your firewall to allow packets through.

And it all just works. Your SG routes traffic for 0.0.0.0/0 -- that is, the whole Internet -- through the tunnel to his SG, which then sends it onward as if it came from his subnet. When traffic for the extruded subnet arrives at his SG, it gets sent through the tunnel to your SG, which passes it to the right machine.

Remember that when ipsec_manual or ipsec_auto takes a connection down, it does not undo the route it made for that connection. This lets you take a connection down and bring up a new one, or a modified version of the old one, without having to rebuild the route it uses and without any risk of packets which should use IPsec accidentally going out in the clear. Because the route always points into KLIPS, the packets will always go there. Because KLIPS temporarily has no idea what to do with them (no eroute for them), they will be discarded.

If you do want to take the route down, this is what the "unroute" operation in manual and auto is for. Just do an unroute after doing the down.

Note that the route for a connection may have replaced an existing non-IPsec route. Nothing in Linux FreeS/WAN will put that pre-IPsec route back. If you need it back, you have to create it with the route command.

Road Warrior with virtual IP address

Please note that Super FreeS/WAN now features DHCP-over-IPsec, which is an alternate procedure for Virtual IP address assignment.

Here is a mailing list message about another way to configure for road warrior support:

Subject: Re: linux-ipsec: understanding the vpn
   Date: Thu, 28 Oct 1999 10:43:22 -0400
   From: Irving Reid <irving@nevex.com>

>  local-------linux------internet------mobile
>  LAN        box                         user
>  ...

>  now when the mobile user connects to the linux box
>  it is given a virtual IP address, i have configured it to
>  be in the 10.x.x.x range. mobile user and linux box 
>  have a tunnel between them with these IP addresses.

>   Uptil this all is fine.

If it is possible to configure your mobile client software *not* to
use a virtual IP address, that will make your life easier. It is easier
to configure FreeS/WAN to use the actual address the mobile user gets
from its ISP.

Unfortunately, some Windows clients don't let you choose.

>  what i would like to know is that how does the mobile
>  user communicate with other computers on the local
>  LAN , of course with the vpn ?

>   what IP address should the local LAN 
>  computers have ? I guess their default gateway 
>  should be the linux box ? and does the linux box need
>  to be a 2 NIC card box or one is fine.

As someone else stated, yes, the Linux box would usually be the default
IP gateway for the local lan.

However...

If you mobile user has software that *must* use a virtual IP address,
the whole picture changes. Nobody has put much effort into getting
FreeS/WAN to play well in this environment, but here's a sketch of one
approach:

Local Lan 1.0.0.0/24
    |
    +- Linux FreeS/WAN 1.0.0.2
    |
    | 1.0.0.1
 Router
    | 2.0.0.1
    |
Internet
    |
    | 3.0.0.1
Mobile User
      Virtual Address: 1.0.0.3

Note that the Local Lan network (1.0.0.x) can be registered, routable
addresses.

Now, the Mobile User sets up an IPSec security association with the
Linux box (1.0.0.2); it should ESP encapsulate all traffic to the
network 1.0.0.x **EXCEPT** UDP port 500. 500/udp is required for the key
negotiation, which needs to work outside of the IPSec tunnel.

On the Linux side, there's a bunch of stuff you need to do by hand (for
now). FreeS/WAN should correctly handle setting up the IPSec SA and
routes, but I haven't tested it so this may not work...

The FreeS/WAN conn should look like:

conn mobile
        right=1.0.0.2
        rightsubnet=1.0.0.0/24
        rightnexthop=1.0.0.1
        left=0.0.0.0  # The infamous "road warrior"
        leftsubnet=1.0.0.3/32

Note that the left subnet contains *only* the remote host's virtual
address.

Hopefully the routing table on the FreeS/WAN box ends up looking like
this:

% netstat -rn
Kernel IP routing table
Destination     Gateway      Genmask         Flags   MSS Window  irtt Iface
1.0.0.0         0.0.0.0      255.255.255.0   U      1500 0          0 eth0
127.0.0.0       0.0.0.0      255.0.0.0       U      3584 0          0 lo
0.0.0.0         1.0.0.1      0.0.0.0         UG     1500 0          0 eth0
1.0.0.3         1.0.0.1      255.255.255.255 UG     1433 0          0 ipsec0

So, if anybody sends a packet for 1.0.0.3 to the Linux box, it should
get bundled up and sent through the tunnel. To get the packets for
1.0.0.3 to the Linux box in the first place, you need to use "proxy
ARP".

How this works is: when a host or router on the local Ethernet segment
wants to send a packet to 1.0.0.3, it sends out an Ethernet level
broadcast "ARP request". If 1.0.0.3 was on the local LAN, it would
reply, saying "send IP packets for 1.0.0.3 to my Ethernet address".

Instead, you need to set up the Linux box so that _it_ answers ARP
requests for 1.0.0.3, even though that isn't its IP address. That
convinces everyone else on the lan to send 1.0.0.3 packets to the Linux
box, where the usual FreeS/WAN processing and routing take over.

% arp -i eth0 -s 1.0.0.3 -D eth0 pub

This says, if you see an ARP request on interface eth0 asking for
1.0.0.3, respond with the Ethernet address of interface eth0.

Now, as I said at the very beginning, if it is *at all* possible to
configure your client *not* to use the virtual IP address, you can avoid
this whole mess.

Dynamic Network Interfaces

Sometimes you have to cope with a situation where the network interface(s) aren't all there at boot. The common example is notebooks with PCMCIA.

Basics

The key issue here is that the config setup section of the /etc/ipsec.conf configuration file lists the connection between ipsecN and hardware interfaces, in the interfaces= variable. At any time when ipsec setup start or ipsec setup restart is run this variable must correspond to the current real situation. More precisely, it must not mention any hardware interfaces which don't currently exist. The difficulty is that an ipsec setup start command is normally run at boot time so interfaces that are not up then are mis-handled.

Boot Time

Normally, an ipsec setup start is run at boot time. However, if the hardware situation at boot time is uncertain, one of two things must be done.

Change Time

When the hardware *is* in place, IPsec has to be made aware of it. Someday there may be a nice way to do this.

Right now, the way to do it is to fix the /etc/ipsec.conf file appropriately, so interfaces reflects the new situation, and then restart the IPsec subsystem. This does break any existing IPsec connections.

If IPsec wasn't brought up at boot time, do

        ipsec setup start
while if it was, do
        ipsec setup restart
which won't be as quick.

If some of the hardware is to be taken out, before doing that, amend the configuration file so interfaces no longer includes it, and do

        ipsec setup restart

Again, this breaks any existing connections.

Unencrypted tunnels

Sometimes you might want to create a tunnel without encryption. Often this is a bad idea, even if you have some data which need not be private. See this discussion.

The IPsec protocols provide two ways to do build such tunnels:

using ESP with null encryption
not supported by FreeS/WAN
using AH without ESP
supported for manually keyed connections
possible with explicit commands via ipsec_whack(8) (see this list message)
not supported in the ipsec_auto(8) scripts.
One situation in which this comes up is when otherwise some data would be encrypted twice. Alice wants a secure tunnel from her machine to Bob's. Since she's behind one security gateway and he's behind another, part of the tunnel that they build passes through the tunnel that their site admins have built between the gateways. All of Alice and Bob's messages are encrypted twice.

There are several ways to handle this.

Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


Installing FreeS/WAN

This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

Requirements

To install FreeS/WAN you must:

Choose your install method

There are three basic ways to get FreeS/WAN onto your system:

FreeS/WAN ships with some Linuxes

FreeS/WAN comes with these distributions.

If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

FreeS/WAN may be altered...

Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

You might need to create an authentication keypair

If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

To do this, become root, and type:

    ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
    chmod 600 /etc/ipsec.secrets

where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

The resulting ipsec.secrets looks like:

: RSA   {
        # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
        # for signatures only, UNSAFE FOR ENCRYPTION
        #pubkey=0sAQOFppfeE3cC7wqJi...
        Modulus: 0x85a697de137702ef0...
        # everything after this point is secret
        PrivateExponent: 0x16466ea5033e807...
        Prime1: 0xdfb5003c8947b7cc88759065...
        Prime2: 0x98f199b9149fde11ec956c814...
        Exponent1: 0x9523557db0da7a885af90aee...
        Exponent2: 0x65f6667b63153eb69db8f300dbb...
        Coefficient: 0x90ad00415d3ca17bebff123413fc518...
        }
# do not change the indenting of that "}"

In the actual file, the strings are much longer.

Start and test FreeS/WAN

You can now start FreeS/WAN and test whether it's been successfully installed..

RPM install

These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

Download RPMs

Decide which functionality you need:

For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

    freeswan-userland-2.03.9-0.i386.rpm

Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

Change to your new FreeS/WAN directory, and make and install the

For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

    uname -r

Get a kernel module which matches that version. For example:

    freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

Get FreeS/WAN utilities to match. For example:

    freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

For freeswan.org RPMs: check signatures

While you're at our ftp site, grab the RPM signing key

    freeswan-rpmsign.asc

If you're running RedHat 8.x or later, import this key into the RPM database:

    rpm --import freeswan-rpmsign.asc

For RedHat 7.x systems, you'll need to add it to your PGP keyring:

    pgp -ka freeswan-rpmsign.asc

Check the digital signatures on both RPMs using:

    rpm --checksig freeswan*.rpm 

You should see that these signatures are good:

    freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
    freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

Install the RPMs

Become root:

    su

For a first time install, use:

    rpm -ivh freeswan*.rpm

To upgrade existing RPMs (and keep all .conf files in place), use:

    rpm -Uvh freeswan*.rpm

If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

Start and Test FreeS/WAN

Now, start FreeS/WAN and test your install.

Install from Source

Decide what functionality you need

Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become root, and type:

        ipsec newhostkey --output /etc/ipsec.secrets --hostname xy.example.com
        chmod 600 /etc/ipsec.secrets

    where you replace xy.example.com with your machine's fully-qualified domain name. Generate some randomness, for example by wiggling your mouse, to speed the process.

    The resulting ipsec.secrets looks like:

    : RSA   {
            # RSA 2192 bits   xy.example.com   Sun Jun 8 13:42:19 2003
            # for signatures only, UNSAFE FOR ENCRYPTION
            #pubkey=0sAQOFppfeE3cC7wqJi...
            Modulus: 0x85a697de137702ef0...
            # everything after this point is secret
            PrivateExponent: 0x16466ea5033e807...
            Prime1: 0xdfb5003c8947b7cc88759065...
            Prime2: 0x98f199b9149fde11ec956c814...
            Exponent1: 0x9523557db0da7a885af90aee...
            Exponent2: 0x65f6667b63153eb69db8f300dbb...
            Coefficient: 0x90ad00415d3ca17bebff123413fc518...
            }
    # do not change the indenting of that "}"

    In the actual file, the strings are much longer.

    Start and test FreeS/WAN

    You can now start FreeS/WAN and test whether it's been successfully installed..

    RPM install

    These instructions are for a recent Red Hat with a stock Red Hat kernel. We know that Mandrake and SUSE also produce FreeS/WAN RPMs. If you're running either, install using your distribution's tools.

    Download RPMs

    Decide which functionality you need:

    For 2.6 kernels, get the latest FreeS/WAN userland RPM, for example:

        freeswan-userland-2.03.9-0.i386.rpm

    Note: FreeS/WAN's support for 2.6 kernel IPsec is preliminary. Please see 2.6.known-issues, and the latest mailing list reports.

    Change to your new FreeS/WAN directory, and make and install the

    For 2.4 kernels, get both kernel and userland RPMs. Check your kernel version with

        uname -r

    Get a kernel module which matches that version. For example:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm

    Note: These modules will only work on the Red Hat kernel they were built for, since they are very sensitive to small changes in the kernel.

    Get FreeS/WAN utilities to match. For example:

        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm

    For freeswan.org RPMs: check signatures

    While you're at our ftp site, grab the RPM signing key

        freeswan-rpmsign.asc

    If you're running RedHat 8.x or later, import this key into the RPM database:

        rpm --import freeswan-rpmsign.asc

    For RedHat 7.x systems, you'll need to add it to your PGP keyring:

        pgp -ka freeswan-rpmsign.asc

    Check the digital signatures on both RPMs using:

        rpm --checksig freeswan*.rpm 

    You should see that these signatures are good:

        freeswan-module-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK
        freeswan-userland-2.03_2.4.20_20.9-0.i386.rpm: pgp md5 OK

    Install the RPMs

    Become root:

        su

    For a first time install, use:

        rpm -ivh freeswan*.rpm

    To upgrade existing RPMs (and keep all .conf files in place), use:

        rpm -Uvh freeswan*.rpm

    If you're upgrading from FreeS/WAN 1.x to 2.x RPMs, and encounter problems, see this note.

    Start and Test FreeS/WAN

    Now, start FreeS/WAN and test your install.

    Install from Source

    Decide what functionality you need

    Your choices are:

  • Use a plain IP-in-IP tunnel. These are not well documented. A good starting point is in the Linux kernel source tree, in /usr/src/linux/drivers/net/README.tunnel.
  • Use a manually-keyed AH-only tunnel.
  • Note that if Alice and Bob want end-to-end security, they must build a tunnel end-to-end between their machines or use some other end-to-end tool such as PGP or SSL that suits their data. The only question is whether the admins build some special unencrypted tunnel for those already-encrypted packets.


    Installing FreeS/WAN

    This document will teach you how to install Linux FreeS/WAN. If your distribution comes with Linux FreeS/WAN, we offer tips to get you started.

    Requirements

    To install FreeS/WAN you must:

    Choose your install method

    There are three basic ways to get FreeS/WAN onto your system:

    FreeS/WAN ships with some Linuxes

    FreeS/WAN comes with these distributions.

    If you're running one of these, include FreeS/WAN in the choices you make during installation, or add it later using the distribution's tools.

    FreeS/WAN may be altered...

    Your distribution may have integrated extra features, such as Andreas Steffen's X.509 patch, into FreeS/WAN. It may also use custom startup script locations or directory names.

    You might need to create an authentication keypair

    If your FreeS/WAN came with your distribution, you may wish to generate a fresh RSA key pair. FreeS/WAN will use these keys for authentication.

    To do this, become roo