Paul gives all the gory details about the what and why of firewalls, then shows you how to build one of your very own.(Webmonkey)

This tutorial discusses how the TIS Firewall Toolkit can be used to control access to your network from the Internet.

This article is a general introduction to network security issues and solutions in the Internet; emphasis is placed on route filters and firewalls. It is not intended as a guide to setting up a secure network; its purpose is merely as an overview.