I have a 1602 cisco router as my default gateway on a small ISP It is attached to a 56k frame relay circuit that connects to my internet backbone. this router is up and functioning perfectly. I want to implement a linux Firewall running Ipchains. I have two nics configured and I can ping to both of them from any work station on my internal network. Eth0 is connected to my switching hub and the linux firewall can access the router and the internet.

But when I replace the cat 5 cable that runs from the router to the switch ....with a cable theat runs from The 2nd nic (eth10 to the aforementioned ETH0 on the cisco router I lose all connectivity to and from the internal network.

This should be easy.. Im just using the Linux firewall which has no rules setup and a default poicy on all chains "Accept" ...as a pass through to and from the switch and router. when the firewall is attached to the cisco router I lose the link light on the router but I can ping both nic cards and when both cards are cabled to the switch They can both access the internet via the router.

Help.. Ive been at this for over ten hours.... all I want to do is implement a firewall using Linux and Iptables in between the router and switch ..please tell me it isnt this hard!!

Any Help and Ill trade free kayak lessons!!

Jeff