# Installing &debian-gnu; over Parallel Line IP (PLIP)

This section explains how to install &debian-gnu; on a computer without an Ethernet card, but with just a remote gateway computer attached via a Null-Modem cable (also called Null-Printer cable). The gateway computer should be connected to a network that has a &debian; mirror on it (e.g. to the Internet).

In the example in this appendix we will set up a PLIP connection using a gateway connected to the Internet over a dial-up connection (ppp0). We will use IP addresses 192.168.0.1 and 192.168.0.2 for the PLIP interfaces on the target system and the source system respectively (these addresses should be unused within your network address space).

The PLIP connection set up during the installation will also be available after the reboot into the installed system (see boot-new).

Before you start, you will need to check the BIOS configuration (IO base address and IRQ) for the parallel ports of both the source and target systems. The most common values are `io=0x378`, `irq=7`.

## Requirements

- A target computer, called target, where &debian; will be installed.

- System installation media; see installation-media.

- Another computer connected to the Internet, called source, that will function as the gateway.

- A DB-25 Null-Modem cable. See the PLIP-Install-HOWTO for more information on this cable and instructions how to make your own.

## Setting up source

The following shell script is a simple example of how to configure the source computer as a gateway to the Internet using ppp0.

    #!/bin/sh

    # We remove running modules from kernel to avoid conflicts and to
    # reconfigure them manually.
    modprobe -r lp parport_pc
    modprobe parport_pc io=0x378 irq=7
    modprobe plip

    # Configure the plip interface (plip0 for me, see dmesg | grep plip)
    ifconfig plip0 192.168.0.2 pointopoint 192.168.0.1 netmask 255.255.255.255 up

    # Configure gateway
    modprobe iptable_nat
    iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
    echo 1 > /proc/sys/net/ipv4/ip_forward

## Installing target

Boot the installation media. The installation needs to be run in expert mode; enter `expert` at the boot prompt. If you need to set parameters for kernel modules, you also need to do this at the boot prompt. For example, to boot the installer and set values for the io and irq options for the parport_pc module, enter the following at the boot prompt:

    expert parport_pc.io=0x378 parport_pc.irq=7

Below are the answers that should be given during various stages of the installation.

1. Load installer components from installation media

   Select the `plip-modules` option from the list; this will make the PLIP drivers available to the installation system.

2. Detect network hardware

   - If target does have a network card, a list of driver modules for detected cards will be shown. If you want to force &d-i; to use plip instead, you have to deselect all listed driver modules. Obviously, if target doesn't have a network card, the installer will not show this list.

   - Because no network card was detected/selected earlier, the installer will ask you to select a network driver module from a list. Select the `plip` module.

3. Configure the network

   - Auto-configure network with DHCP: No

   - IP address: ``192.168.0.1``

   - Point-to-point address: ``192.168.0.2``

   - Name server addresses: you can enter the same addresses used on source (see `/etc/resolv.conf`)