Mastering Linux Security and Hardening

Uncomplicated Firewall for Ubuntu systems

The Uncomplicated Firewall is already installed on your Ubuntu machine. It still uses the iptables service, but it offers a vastly simplified set of commands. Perform just one simple command to enable it, and you have a good, preconfigured firewall. There's a graphical frontend for use on desktop machines, but since we're learning about server security, we'll just cover the command-line utility here.