howto Name eth[0 .. n-1] in kernel 2.4.18 vs earlier kernels?

I just upgraded to 2.4.18 on debian woody and built my own kernel. In the past, there was an alias for "tulip" in the modules file. This named my NIC eth0. In my firewall, it named the NICs eth0 and eth1

In 2.4.18 I cannot seem to find the place to name the NICs. Where can this be done? It will be a big issue on my firewall as eth0 MUST remain the external nic.

Thankyou