Gufw is an easy, intuitive, way to manage your Ubuntu firewall.
It supports common tasks such as allowing or blocking pre-configured services, common P2P, or individual IP/port(s), and many others!
Gufw is free software licenced under GPL3.
It’s an interface powered by ufw.

Gufw is available from Ubuntu Software Center, or you can download from Launchpad.net.

Start Gufw from System -> Administration -> Firewall Configuration.