It has a personal firewall that a complete idiot can set up. I assume you are not a complete idiot :)
What you get is a real firewall with an open internal network, which is probably what you want at home.
It's literally a matter of picking choices in YaST and saying "Accept".
Any cheap box can do as the firewall machine. Just make sure you do the setup with no X server. The text YaST interface is text based and runs in a console.
The firewall machine needs two standard NICs, 64M of RAM or more, and a cheap disk.