Someone in one of the BSD newsgroups mentioned something about FreeBSD
supporting firewalling.  I've looked on my NetBSD system (yes, I know
they're not the same, but I thought the support might be common to the
4.4-lite source base) and wasn't able to find anything.  Does NetBSD
support firewalling/packet filtering?  If so, how do I set it up?  Do
I need any additional software?