Note: This tutorial will cover setting up a firewalld firewall and making your system a router. firewalld is preinstalled on CentOS and Red Hat Enterprise Linux systems.

To follow the contents of this tutorial, be sure to follow inside a terminal. Most operations require super user priviliges. For the sake of the tutorial, be sure all commands are executed as root or execute all commands with sudo.

Replace any instances of vi with your command-line editor of choice. Possible editors include:

• vi