Cross-platform Pf Guide
Cross-platform Pf GuideWhile the official OpenBSD Pf guide is very good, I recommend those wishing to learn more about the Pf firewall check out Peter N. M. Hansteen's Firewalling with Pf guide. I like this document because it shows how to get Pf working on OpenBSD, FreeBSD, and NetBSD. Peter also covers the most common deployment scenarios and he addresses topics I consider important. Check it out if you're considering a Pf-based firewall solution.