Firing up Firewalls
This documentation discusses how to set up a Firewall for different distributions.
Discover How To Secure My Firewall HOWTOs
Remote-Office Firewalls
This documentation discusses supporting telecommuters remote small-office sites and how you can setup a firewall to protect the network from being very useful for obscuring a hacker's tracks on the way to his or her final destination.
IPFilter resources
IP Filter is a great little firewall package. It does just about everything other free firewalls (ipfwadm, ipchains, ipfw) do, but it's also portable and does neat stuff the others don't.
