I'm sorry, I didn't understand your question, and from the answers that I've seen, others are confused as well.
Are you looking for a way to firewall your linux workstation or to build a standalone linux firewall?
hidden75's response is good for protecting a linux box that you will actively log into and run applications on, while KarveR's response is excellent for a linux box that will only be a firewall.
initialdrifteg6's response I think will work in either case, but is geared more toward the workstation.
Pretty much all linux firewalls take advantage of IPTables/IPChains, but how you write the rules differs greatly based on which interface you use.
pansophic