Linux firewall options

["Mayne, Peter" <Peter.Mayne () compaq com>]

Given Linux (say RedHat 6.0 or greater) as a base, what options are
available to build firewalls? Is there a "Linux firewalls" site somewhere?

ipchains is an obvious place to start for basic packet filtering
functionality, but I'd prefer something more substantial. I could use Apache
or Squid (depending on circumstances) as a Web proxy, for instance.

I don't think FWTK can be used in a commercial environment because of the
license restrictions. Is there something similar out there that is otherwise
usable?

I realise this is a "how long is a piece of string?" type question, but
there must be different packages, freeware, shareware, open source,
commercial, etc suitable for different uses.

PJDM
----
Peter Mayne, Compaq Computer Australia, Canberra, ACT
These are my opinions, and have nothing to do with Compaq.
"The wise man knows that he knows nothing." - Bill. "That's us, dude!" -
Ted.