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