Stateful Filtering Extensions for IPFW

Prior to the creation of the FreeBSD Foundation its predecessor, FreeBSD, Inc., contracted with Luigi Rizzo to enhance FreeBSD’s packet filtering facility with a stateful filtering feature. This was an oft-requested feature to enhance FreeBSD’s ability to serve as an effective and flexible network firewall. The Foundation elected to assume responsibility for funding this contract. Under this arrangement, Luigi added the stateful filtering feature to the FreeBSD operating system early in 2000. Since then he has made ongoing enhancements to the code.