I have a very easy example of how to start and make a complex firewall
ruleset in my site in this article I am pasting, check it out:
http://www.debian-gnu.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=6
Hope you like it
--
Daniel Ferradal
daniel@debian-gnu.com
Registered Linux user # 128322
http://www.debian-gnu.com