The OpenBSD PF Packet Filter Book: PF for NetBSD, FreeBSD, DragonFly, and OpenBSD
Ships in 3-5 business days
As an expanded and improved version of the PF FAQ, this indexed and cross-referenced book covers the PF packet filtering, firewalling, and quality of service software for NetBSD, OpenBSD, FreeBSD, and DragonFly. Also a chapter on spamd, the greylisting tarpit, is included.
See the book's webpage at http://www.reedmedia.net/books/pf-book/.