Firewall

Does anyone know of a easy to install linux firewall (slackware). I have tried quite a few of them, being the linux newb I am either couldnt install them, or couldnt install them correctly. It is pretty much a workstation, a place for me to learn how to use linux. Later on I may add in a ftp server or a ventrilo server, so the firewall needs the functionality to allow me to host as well.