FirewallBuilder

You've built a firewall script to protect a server, but after you ran the script, X (KDE, Gnome) won't start anymore.

The reason for this is the same as in the DNS problem -- you need a rule to permit processes to communicate with other processes running on the same machine. This can easily be achieved with the following rule added to the loopback interface:

Figure 15.5. Any to any on firewall