The built-in features available in Douane
Simple as answering a question As soon as you have access to a network, applications will try to send whatever information. Behind your traffic (emails, social networks, online videos, ...) you will discover some activities that you did not expected. Douane will block all the unknown traffic and let you decide if you allow it or not via this dialog box. Clicking the Allow or Deny buttons will create the rule for you.
A single place to control Douane
This is the control panel.
It will allow you to start and stop the firewall, to enable/disable the firewall autostart at boot, let you configure the rules and keep you informed by showing you the latest tweets!
My experience with instalation on ubuntu
1) add repository
sudo apt-add-repository ppa:zedtux/douane
2) update sources
sudo apt-get update
3) download latest stable version from github
*in repository you only has a testing version, and for my is don't work
4) install douane-configurator
sudo apt-get install douane-configurator
5) reboot your system and enjoy it :)