This post title is the name of a Fedora configuration tool which is getting better with each release. Firewall configuration used to scare new users, but now things are a lot easier. Having a nice and simple GUI, system-config-firewall (which is written in Python) offers default iptables rules for both desktop and server users and a wizard for beginners.
The user can switch from simple mode to advanced mode by changing the User Skill Level from the Options menu.
Changing the skill level to expert mode will give you access to additional options such as Masquerading and Port Forwarding. You’ll also be able to load custom rules from a file and set custom ICMP types to be rejected.
Once you’ve finished with the configuration and clicked the Apply button, the new rules become active. If anything goes wrong, you can always either disable the firewall or load the default rules.
Upon a successful Fedora 11 installation, the firewall is active by default, blocking anything but SSH access which is a good thing considering that a regular user doesn’t need more than that.