IPTABLES help

[Dan de Haan]

I am trying to write some IPTABLES rules.  These should be simple, but
arent working for me.  What I want to do is this;

The system has two ethernet adapters eth1 and eth2.  I want it to
forward TCP traffic on a specific port from devices on eth1 to a server
on eth0.  It has a dhcp client on eth0 and dhcp serve on eth1.  It must
drop evertthing but ping and the packets I need forwarded.

Can aynone give me a hint as to were to go?

	-Dan