Hi !
I'm trying to use a computer as a very simple gateway.
This is the topology of my network :

192.168.2.0/24 ------ GATEWAY ------ 192.168.1.0/24

I configured my gateway like this :

eth0 : 192.168.2.1
eth1 : 192.168.1.1

I can ping 192.168.1.0/24 from GATEWAY
I can ping 192.168.2.0/24 from GATEWAY

I set /proc/sys/net/ipv4/ip_forward at 1.

Problem :
I can't ping 192.168.2.0 network from 192.168.1.0 network
All 192.168.1.0 computers send data to the GATEWAY but does not forward packets.

Why ?
My configuration ?
Ubuntu 8.04 server ?
Other ideas ?

Thank you

Could be firewall, could be routes could be something else.

Can you post

sudo iptables -L FORWARD

and

sudo route

?