Can someone comment on the various Packet Filters (PF) available on free OSes?
Here's my understanding which I'm sure is not quite correct.
Linux has IPFW/IPFWADM. I guess it is a Packet Filter (PF) except when you
use IP Masquerade in which case it becomes a Stateful Packet Filter (SPF) +
Network Address Translation (NAT) with a single-IP outgoing.
FreeBSD has IPFW (different from Linux IPFW). I guess it is a PF.
OpenBSD/NetBSD has IPFilter which is a PF, SPF, and NAT.
(IPFilter can be compiled for all OSes.)
Are there others?