Thanks for the quick reply!
We are using iptables under Gentoo Linux. The rules where added before my time at the company, In fact I have been with the company less then a week
Everything was working great until Friday afternoon when the internet to all of the systems on the network went down. After about 4 hours the Gentoo box came back online, However the windows boxes did not. We are running on a T1 line with static IPs for the servers and a mix of DHCP and Static IPs for the workstations.
The windows boxes can ping the Gentoo box, And the Gentoo Box can ping the windows boxes, However the windows boxes are still without internet.
It may also help to note that this server uses 4 NICs, I have only a vague idea why. We do have a field offices that connect to an NT box we have via this Gentoo server, However since the internet went down, They are unable to get in as well.