mfw allows multiple firewall configurations to be managed from the commandline on Mac OS X. Multiple firewall modes (and easy means of selecting between them) are useful on laptops, where one may want a default paranoid firewall, a mode for network scanning with nmap, modes for various networked games, or to run a software Network Address Translation (NAT) wireless base station.
pks-commands.php3 allows your Web server to search and add PGP/GPG keys from the public keys out there. It takes the TCP 11371 port connection and does it all on the web server. It is good in environments where the client machines are unable to get to arbitrary TCP ports (such as behind tightened firewalls).
IsinGlass is a firewall setup script designed to protect dial-up users (but also useful for others). It protects your system against security holes in programs the user may not even know they're running. Most users can run it "out of the box" without any configuration required. It will automatically detects network interfaces and IP addresses. Now works with ipchains.