OpenBSD s stateful packet filter, PF, is the heart of the OpenBSD firewall. With more and more services placing high demands on bandwidth and an increasingly hostile Internet environment, no sysadmin can afford to be without PF expertise. The third edition of The Book of PF covers the most up-to-date developments in PF, including new content on IPv6, dual stack configurations, the 'queues and priorities' traffic-shaping system, NAT and redirection,...