# Configuring the Network

As you enter this step, if the system detects that you have more than one network device, you'll be asked to choose which device will be your primary network interface, i.e. the one which you want to use for installation. The other interfaces won't be configured at this time. You may configure additional interfaces after installation is complete; see the

interfaces

5 man page.

## Automatic network configuration

By default, &d-i; tries to configure your computer's network automatically as far as possible. If the automatic configuration fails, that may be caused by many factors ranging from an unplugged network cable to missing infrastructure for automatic configuration. For further explanation in case of errors, check the error messages on the fourth console. In any case, you will be asked if you want to retry, or if you want to perform a manual setup. Sometimes the network services used for autoconfiguration can be slow in their responses, so if you are sure everything is in place, simply start the autoconfiguration attempt again. If autoconfiguration fails repeatedly, you can instead choose the manual network setup.

## Manual network configuration

The manual network setup in turn asks you a number of questions about your network, notably `IP address`, `Netmask`, `Gateway`, `Name server addresses`, and a `Hostname`. Moreover, if you have a wireless network interface, you will be asked to provide your `Wireless ESSID` (wireless network name) and a `WEP key` or `WPA/WPA2 passphrase`. Fill in the answers from needed-info.

Some technical details you might, or might not, find handy: the program assumes the network IP address is the bitwise-AND of your system's IP address and your netmask. The default broadcast address is calculated as the bitwise OR of your system's IP address with the bitwise negation of the netmask. It will also guess your gateway. If you can't find any of these answers, use the offered defaults — if necessary, you can change them by editing `/etc/network/interfaces` once the system has been installed.

## IPv4 and IPv6

From &debian-gnu; 7.0 (Wheezy) onwards, &d-i; supports IPv6 as well as the classic IPv4. All combinations of IPv4 and IPv6 (IPv4-only, IPv6-only and dual-stack configurations) are supported.

Autoconfiguration for IPv4 is done via DHCP (Dynamic Host Configuration Protocol). Autoconfiguration for IPv6 supports stateless autoconfiguration using NDP (Neighbor Discovery Protocol, including recursive DNS server (RDNSS) assignment), stateful autoconfiguration via DHCPv6 and mixed stateless/stateful autoconfiguration (address configuration via NDP, additional parameters via DHCPv6).