Mastering Linux Security and Hardening

An overview of iptables

A common misconception is that iptables is the name of the Linux firewall. In reality, the name of the Linux firewall is netfilter and every Linux distro has it built-in. What we know as iptables is just one of several command-line utilities that we can use to manage netfilter. It was originally introduced as a feature of Linux kernel, version 2.6, so it's been around for a long time. With iptables, you do have a few advantages:

• It's been around long enough that most Linux admins already know how to use it
• It's easy to use iptables commands in shell scripts to create your own custom firewall configuration
• It has great flexibility, in that you can use it to set up a simple port filter, a router, or a virtual private ...