Hi,
I have a web/mail server (using linux) for 3 very small websites that is behind a 4-port router and has a built in firewall (It's a home router, so the firewall is not very configurable -- plus it doesn't filter outgoing traffic, only incoming.) The firewall only lets port 80 and 25 be visible to the internet. Everything else (ftp,ssh) is only accessible to the four comp network.

Anyways, is it worth it to configure another firewall on the linux server using ipchains (for extra security)?

-Mike