bgpd - pf integration The BGP protocol is an efficient way to distribute lists of network prefixes, so we integrated bgpd with our packet filter, pf bgpd can add prefixes learned from neighbors into a pf table prefixes are selected using the bgpd filter language tables use a radix tree, very fast even with lots of entries pf tables can be used for pretty much anything: packet filtering redirection to spamd (BGP distributed spam blacklists) QoS processing