Pliris has released Firewalk X 2, a new version of its independent, software-based firewall for Mac OS X. Features include TCP, UDP, and ICMP packet filtering; self optimization; interactive, real-time alerting; the ability to restrict network access to specific applications; user and IP address specific application rules; and more. Registered owners of Firewalk X 1.x may upgrade to version 2 for free. Firewalk X 2 sells for US$49.99.