pfsense is a customized FreeBSD+pf distribution designed for use as a firewall. It wraps many of the features of the pf firewall code in an easy-to-use web interface.
pfSense is an open-source firewall product built on top of FreeBSD and the OpenBSD pf firewall.
It provides a graphical (web-based) interface for configuring and managing firewall rules, as well as viewing traffic and firewall decisions (accept/reject).
pfsense is available as a pre-built applicance (such as OPNSense or StrongBochs) or as installable software directly from the pfSense project's site.
pfsense is similar in concept to m0n0wall, however as of this writing m0n0wall uses the ipfilter packet filter.
