Related link: http://www.deadly.org/article.php3?sid=20030325141427
The OpenBSD packet filter has been ported to FreeBSD and NetBSD. If you plan to move from ipfw to pf, then this might help to get you started (just remember to replace
modify state with
UPDATE 2003-05-03, 10:57 GMT+1: Max Laier wrote to inform me that pf for FreeBSD has a new home. Thank you, Max!