Configure a Firewall with Arno Iptables in Debian 5 (Lenny)

Protecting access to your Linode with the arno-iptables-firewall package.

Control Network Traffic with iptables

Use iptables to manage Netfilter rules.

How to Configure a Firewall with UFW

Use UFW (Uncomplicated Firewall) to manage your firewall on Ubuntu, Debian, or Arch Linux; this guide contains instructions for setting up default rules, adding/removing rules, setting up logging, and some advanced features.

Introduction to FirewallD on CentOS

This guide will introduce you to FirewallD, its notions of zones and services, and show you some basic configuration steps.

Protecting Your Linode with TCP Wrappers

Enhance your server's security through the use of TCP wrappers