This is always a huge topic and it seems simple to many of us but the fact of the matter is we have a lot of "new" people so we need to be clear about this sort of thing. (Note all commands should be run as root or with sudo)

1. To start networking in Backtrack 4 final issue the following command.

/etc/init.d/networking start

This will attempt to start all the interfaces in the /etc/network/interfaces file.

root@bt:~# cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet dhcp

auto eth2
iface eth2 inet dhcp

auto ath0
iface ath0 inet dhcp

auto wlan0
iface wlan0 inet dhcp

If you don't have or don't want some of these interfaces then simply remove the from this file and they will not start.

If you need to set a static IP just set the variables in the /etc/network/interfaces file

auto eth0
iface eth0 inet static
address 192.168.0.100
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1

You will also need to make sure you set a nameserver in /etc/resolv.conf

root@bt:~# cat /etc/resolv.conf
nameserver 192.168.0.1

So for example if all you have is eth0 and wlan0 on your system and you want them both to get a adress via DHCP then remove every thing else for the file with the exception of the lo interface. Here is a example.

root@bt:~# cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto wlan0
iface wlan0 inet dhcp


Now if are lazy and want all this to start at boot you can simply issue this command as root

update-rc.d networking defaults

This will create all the proper sym-links

What about ssh?

So while I am on the subject I may as well go over ssh. In order to use ssh on backtrack 4 final you need to generate the keys first.

sshd-generate

after that you can start ssh like this:

/etc/init.d/ssh start

or you can add it to the boot sequence like this:

update-rc.d ssh defaults

Well thats enough to get up and running. I hope this was somewhat helpful to any one just getting started with backtrack.