Dedicated to Users, Admins and especially Developers of IT-Security Solutions (especially Firewalls) based on Free Software. It features a large Tool overview, some articles on IT-Security and Web Links to other resources.

SANS Internet Storm Center - A global cooperative cyber threat / internet security monitor and alert system. Featuring daily handler diaries with summarizing and analyzing new threats to networks and internet security events.

A comprehensive list of firewall vendors, white papers, resources, and FAQs.

FirewallSupport.com is an online support service specifically focused on firewall security. Content includes: Firewall Security, Firewalls, Gateways, DMZ, NAT, VPN, IPSec, 3DES, AES, MD5, SHA-1, Troubleshooting, Proxy, Encryption, Stateful Inspection, Packet Filtering and others.