Hey, hey,
I've come through a site that might interest guys not too much familiar with linux netfilter(Iptable, Ipchains) config.

You follow the step (DHCP, device, ....) and the web page will generate the scipt for u!

I'll advice not to put your real IP adds in, but I think it's a good tool to learn & progress

http://www.linux-firewall-tools.com/...all/index.html