I've got system debian6-based but almost empty, and I really need to make it work. There is no C compiler so i cant install anything manually, there is no networking system I'm used to on normal ditros, there is no ssh to just monster copy everything from my working squeeze. There was no /etc/network/interfaces neither /etc/init.d/networking. I have copied both through flash, did a script for my eth2, put it into rc.local. I can ping everything in my local network including the gateway. But probably because I have to set my gateway(usually done in interfaces) i am unable to ping anything(access) in the global network which would allow me to apt-get the stuff I need. So this is basically naked system, without almost anything, I've got tar, apt-get some superbasic utilities, but thats it. Hope for help, i.e. how to configure the network manually, not having anything at all.

to start networking try as root

I've got no eth0 even Please read, the problem is much harder than you suspected in your reply.

Just installing debian from cd-1 gives you the basic network tools & CLI, the networking isn't started automatically. Issuing command dhclient eth2 will start network which you can test by pinging google or using apt-get update.
dhclient can be used with eth0 eth1 eth2 or whatever wired network, if you have wireless then you'll most likely need to get another cd maybe cd-2

That is not a debian cd-1, that is custom distro for cpc306 by "fastwel" becuase it is the only distro that runs there. 256mb of ram, vim3d and stuff.
Just "in case". The dhclient eth2 command does nothing, and system hangs, top shows no activity except for itself whatsoever. Pinging py IP-address gives "network is unreachable", by name - "unknown host".

Really need someone with clues or experience, so kinda bump.