pfSense is a free, open-source firewall and router distribution built on FreeBSD, managed entirely through a web interface so that deploying enterprise-grade network protection requires no direct FreeBSD command-line knowledge. Forked from the m0n0wall project in 2004 by Chris Buechler and Scott Ullrich, it bundles firewall, VPN (OpenVPN, IPsec, WireGuard), traffic shaping, load balancing, and captive portal functionality, extendable through an integrated package system. Maintained by Netgate, which also sells pre-configured hardware appliances and a commercial pfSense Plus edition, the free Community Edition remains widely deployed from home labs to corporate networks worldwide, and was the origin project that OPNsense later forked from in 2015.