I wrote a quick checklist, how-to type of article describing how I
quickly make & manage firewalls based on Fedora Core 2. I am a
Windows guy, and the one thing that I won't do with windows is packet
filtering/mangling.
I had quite a bit of difficulty in figuring out how to do all of this,
since linux firewall how-to documents don't seem as good as all of the
OpenBSD firewall stuff I found via google.
Included are some scripts & rpm packages that allow you to monitor
firewall activity. I do all of this from a Windows workstation, of
course. Thank God for putty & filezilla.
http://www.castellan.net/linux_firew..._firewall.html
Hope this helps out other people in their quest to cut costs & improve
services to the end users.