2 NICs configuration problem

[Denham Eva]

Hello list,

To begin with my knowledge on network related subjects is.. er lacking?

Anyway I have this old pc Pentium 200 MMX, 64MB ram. I installed Redhat 9 (Shrike), no X server etc. Later I installed two Network Cards.

The idea is to create a "gateway" or should that be "router"? Also the idea is to study up on the networking stuff.
Configuration something like this...
eth0 172.20.1.50 and eth1 172.20.2.60 on it's own subnet, hope I am clear enough so far:-)

Well after much reading up etc, I used redhat-config-network to configure eth0.
This it "sees" at startup fine, but eth1 it does not.
I then run 
ifconfig eth1 172.20.2.60 netmask 255.255.0.0 broadcast 255.255.2.254
Then eth1 is available, now I don't know for how long it will remain available, I have only booted the machine to see if it won't boot recognizing both NICs, because I can't figure out how to get the info to "stick" so that it will startup at boot.

Apologies for the long winded mail, but
Does anyone know how I can fix this? OR
Direct me to a Howto which guides one through a similar setup?

Best Regards
Denham Eva