Complete guide to iptables implementation

I’ve been wanting to put this article together for some time, a complete guide to implementing iptables on a Linux Server.

Firstly, my assumptions:

• You have a reasonable grasp of Linux and Iptables
• You want to use Iptables to secure a Linux server

The Basics Iptables has by default three chains for the FILTER table:

• INPUT
• OUTPUT
• FORWARD

In this case, we’re going to focus on the INPUT chain (Incoming to firewall. For packets coming to the local server)

Implementation

Automation I implement these rules using the puppet-iptables module. The module is regularly updated and has a very large feature-set.

References: https://gist.github.com/jirutka/3742890 http://www.cyberciti.biz/tips/linux-iptables-10-how-to-block-common-attack.html