iptables need help

[jimmywyh]

hi guys,

i'm planning to setup a firewall using iptables (fedora 4). my network looks like this..

lan1(eth1)---|
|-----------ext(eth0)-----router------Intranet
lan2(eth2)---|


how do i start...lan1 and lan2 cannot see each other and inbound access are not allowed...nat nat are involved here coz we're in an intranet environment..

I've trying to write a new script but found no related example after googling. How do i go about this..??
Can i just replace the existing iptables script in /etc/init.d with the new script i'm planning to create..
besides the 3 default chain i should create new chain for eth1 and eth2 right..need some guidance...
my routing is running..thanks..

[framp]

I am sorry - but I neither get your config nor your problem.