Infowar.Com Forums
Winn Schwartau's (author of "Information Warfare") forums for discussing information warfare, network security and legal hacking. Additional forums include hacking and programming tutorials and challenges.

SecurityForumX
Security forums devoted to discussing news items found in the related SecurityNewsPortal website. Discussion topics include viruses, firewalls and system exploits and weaknesses.

Security Forums Dot Com
Offers support forums on a selection of IT security topics including firewalls, encryption and malicious software. Based in UK.

SecurityRisk
Discussion forums on operating system, database and network security. Topics include security vulnerabilities, audit tools and white papers.

Open CSO Project
Focused on career development in the security industry. Forums cover management and leadership skills, appropriate technical expertise as well as resources helpful to security professionals.

Wilders Security Forums
Security forums covering a wide array of topics including spyware, viruses and privacy software.

Castle Cops
Discussion forums. Subforums include firewalls, homeland security and specific security vendor products. Also offer software reviews and downloads.