OpenBSD up to 2.9 inclusive (2001) used Darren Reed's IPFilter
it was discovered that IPFilter was almost, but not quite BSD licensed - no right to distribute changed versions
- > IPFilter removed on May 29th, 2001
First commit of the new PF code June 24 2001 at 19:48:58 UTC
The OpenBSD 3.0 release was pushed from Nov 1 to Dec 1 by the extra effort
License audit of src tree + ports tree followed, removed *lots* of problems for everybody