NetBSD is using/will be using? ‘npf’, a new
version of pf similarly-named-but completely-different firewall from pf. Hubert Feyrer put together a bunch of links talking about it. I link this because DragonFly is using a version of pf equivalent to what OpenBSD 4.8, and there’s been some discussion of what to do next; it appears FreeBSD and NetBSD are forking off separately from OpenBSD’s version.
Update: npf and pf share 2 letters in the name and nothing else, as Joerg told me – corrected.