Patchkit for FreeBSD 2.1.5 or later to add kernel AppleTalk support.
README
http://prdownloads.sourceforge.net/macipgw/netatalk-fbsd-2.1.5.tar.gz

macipgw, MacIP Gateway for netatalk on FreeBSD:
FreeBSD users: use the port or the package net/macipgw-1.0
SourceForge Project Summary
README
macipgw(8) man page
http://prdownloads.sourceforge.net/macipgw/macipgw-1.0.tar.gz

Tutorial: Configuring atalkd(8) as an AppleTalk router