Operated by the SANS Institute, the ISC provides a user-supported infrastructure for intrusion detection systems to share information about ongoing attacks that span countries, networks, and administrative boundaries.

Intrusion detection focus area; designed to assist discussion on security related topics, and provides a database of security knowledge and resources. It also hosts the BUGTRAQ mailing list.

Distributed Intrusion Detection System. Accepts firewall log excerpts from around the world and you can browse through activity reported to the system. Features a list of the "most wanted" abusive IP addresses.

Large index of computer security resources, including a glossary of Intrusion Detection and Prevention systems.

Intrusion Reporting and Response. Users forward firewall logs that are aggregated and analysed to identify incidents that are reported to the responsible party.

Clearinghouse listing of many of the Internet resources associated with intrusion detection and prevention systems. Includes inventories of commercial products, research projects, and other IDS-centric material.

Provides books, articles, software and other information on penetration testing and other security issues. Geared toward Windows NT/2000/XP Network Administrators.

A source of IDS-related information, including security best practices, audit procedures, penetration testing, and community information.

An excellent index of most currently available IDS and IPS products, including vendor contact information.

Collection of IDS-related resources made available by the linuxsecurity.com community.