Packet Filter (from here on referred to as PF) is OpenBSD's system for 
filtering TCP/IP traffic and doing Network Address Translation. PF is also 
capable of normalizing and conditioning TCP/IP traffic and providing bandwidth
control and packet prioritization. 

Information about pf can be found at the website of Daniel Hartmeier, the
original author of PF: http://www.benzedrine.cx/pf.html and OpenBSD PF FAQ: 

http://www.openbsd.org/faq/pf/

WWW: http://pf4freebsd.love2party.net/

-Max <reports@pf4freebsd.love2party.net>