[CentOS] firewall?

Sat Jul 16 04:33:03 UTC 2011
hadi motamedi <motamedi24 at gmail.com>

Dear All
I need to put my centos 5.6 server as firewall server in fron of a
windows-running node before connecting it to the net. Can you please
let me know what stuff do I need to put on my centos server?
Thank you