A firewall is a basic filter that can provide an efficient protection to your server by only allowing the traffic in and out as the rules of the firewall allows it. Setting up a firewall on a Ubuntu Linux server does not need to be complicated - in fact the one used in this example is called “uncomplicated firewall”.
To get the firewall up and running make sure it’s installed through the package manager.
I’m still enjoying the fresh new Ubunutu 9.04, and one of the nice new features is a firewall – which Canonical calls “Uncomplicated Firewall”. I’m usually not hooked on firewalls, but just for the fun of it I enabled the firewall on my laptop and it seems to work quite well. The firewall doesn’t seem to have any noticeable impact on system performance and as the laptop from time to time visits open wifi’s, it’s probably a good idea to have protection from other users on open networks.