Is ipfw the same as pf in FreeBSD? I'm wondering if references referring to pf in FreeBSD are applicable to ipfw in Mac OS X Snow Leopard? I'd like to know to see if it's worthwhile to consult books on pf for use with Mac OS.
ipfw is like as ipfw on freebsd. :)

ipfw and pf are totally different packet filtering systems. ipfw is the old BSD (Internet Protocol Firewall), and pf (packet filter) comes from the OpenBSD.

pf is much much more powerful as ipfw. In fact, pf is much more powerful as anything other. Here is too much differences, but the main "philosophical one" is:


In IPFW, the first rule in a ruleset what matches a packet "wins" - and next rulesets are not evaluated
In the PF the packet is matched with all rules and the last rule that matches  the packet "wins".


You should consult books, manuals about the "ipfw", not pf.

Btw, here are two nice free applications: NoobProof and WaterRoof - both are helpers for the OSX's ipfw. http://www.hanynet.com/noobproof/