Linux Firewalls
This article describes different types of Linux firewalls: packet-filtering, ipchains, stateful, and layered.
Discover How To Secure My Firewall HOWTOs
Easy Firewall Generator for IPTables
This program generates an iptables firewall script for use with the 2.4 or later linux kernel. It is intended for use on a single system connected to the Internet or a gateway system for a private, internal network.
IPTables HOWTO
This document describes the main functions of the Netfilter Packet filter (IPTables) included in the 2.6.x series kernels.
