Access Control List Resources (Cisco)

• Access Lists: Tricks of the Trade - Certification Zone's White Paper on configuring and deploying Cisco ACLs
• The Cost of Security on Cisco Routers - A Network Computing Tutorial on how implementing access control lists can impact Cisco routers
• Demystifying Cisco Access Control Lists - Network Computing Workshop on using Cisco ACL's
• Increasing Security on IP Networks - Cisco's Guide to network security using their products

Attack, Hacking, and Exploit Information

• AntiOnline - News and information on network security and hacking
• Bindview's RAZOR - A team of researches that produce news and information on network security and system vulnerabilities
• Cult of the Dead Cow - Home of information on BackOrifice
• Fyodor's Playhouse - Lot's of information on known exploits
• Gibson Research - Steve Gibson's collection of security tools, testers, and exploit information
• interhack - Information on network security issues
• NT Bugtraq - NTBugtraq is a mailing list for the discussion of security exploits and security bugs in Windows NT and its related applications
• NT Security - Information on Windows NT security and exploits
• Ping Of Death Page - Information on a flaw in many TCP/IP stacks that can allow a remote user to crash a system with a simple ping
• PPTP Crack - Information on the crack of Microsoft's Point-to-Point Tunneling Protocol
• SATAN Guide - A short paper on using SATAN, includes links to additional resources
• Security Administer's Tool for Analyzing Networks (SATAN) - Information and download sources for SATAN
• Security Administrator's Integrated Network Tool (SAINT) - Tool for performing security assessments
• Security Focus - Enormous collection of security resources and forums and home of bugtraq mailing lists
• Security Tracker - Their purpose in life is to report on computer security vulnerabilities
• TCP Loopback DoS Attack (land.c) and Cisco Devices - From Cisco's Web Site
• X-Force Search - Searchable database of known threats and vulnerabilities, by ISS

Denial of Service (DoS)

• Consensus Roadmap for Defeating Distributed Denial of Service Attacks - SANS institute document that outlines key trends and other factors related to DoS attacks and their prevention
• Denial of Service Attacks - White paper on DoS attacks. By IBM Global Services
• Denial of Service Attacks - White paper on detecting and preventing DoS attacks.  By Concord Communications
• DoShelp.com - Provides a wealth of information and resources on Denial of Service attacks

Firewall Information & Software

• Auditing Your Firewall Setup - A guide to auditing your firewall implementation and rulebase
• Audit My PC - Web-based tool for auditing your firewall vulnerability
• Building a Firewall with LINUX - Informative article by Arthur Donkers
• Cisco SAFE: A security blueprint for enterprise networks - Cisco's best practice information on designing and implementing secure networks
• COAST Internet Firewalls Resources - Large collection of links to firewall information
• Firewall and Proxy Server HOWTO - Mark Grennan's basic guide to setting up a filtering and proxy firewall using LINUX
• Freefire Project - Information and support for freeware firewall users and developers
• Internet Firewalls FAQ - Guide to firewall and network security basics. A must read!
• Linux Security Administrator's Guide - Guide to Linux security and pointers to additional resources
• PhoneBoy's FireWall-1 FAQ - An extensive collection of resources for CheckPoint's FireWall-1
• Public Domain Firewall Software Listing - A fairly complete listing of PD firewall software

Glossaries

• Critical Infrastructure Glossary of Terms and Conditions - From the Critical Infrastructure Assurance Office
• Draft Comprehensive Information Assurance Dictionary (PDF) - From the National Information Assurance Training and Education Center at Idaho State University
• National Information Systems Security (INFOSEC) Glossary - From the National Security Telecommunications and Information Systems Security Instruction (NSTISSI)
• RFC 2828: Internet Security Glossary - From the Internet Society

Government Agencies and Security Organizations

• Computer Emergency Response Team (CERT) - U.S.-funded entity to study Internet security vulnerabilities, handle computer security incidents, publish security alerts, research long-term changes in networked systems, and develop information and training to help network improve security 
• Computer Incident Advisory Capability (CIAC) - U.S. Department of Energy response center for computer security incidents and threats
• Computer Security Institute (CSI) - Computer professional's organization that provides information on protecting network-based systems against attacks
• Forum of Incident Response and Secuirty Teams (FIRST) - Promotes coordination among various incident reponse teams
• International Computer Security Association (ICSA) - Provides security news and information as well as system certification information
• National Infrastructure Protection Center (NIPC) - U.S. based agency that serves as a national critical infrastructure threat assessment, warning, vulnerability, and law enforcement investigation and response entity.
• National Institute of Standards and Technology (NIST) - Computer Security Resource Clearinghouse
• System Administration, Networking, and Security (SANS)  Institute - cooperative research and education organization for sharing network security related information

Intrusion Detection

• Bro - A system for detection network intruders in real-time - a high-performance network intrusion detection system written by Vern Paxson of the Lawrence Berkeley National Laboratory's Network Research Group and of ACIRI
• FAQ: Network Intrusion Detection Systems - A detailed FAQ covering NIDS history, capabilities, and products
• Inferring Internet Denial-of-Service Activity - A white paper on using intrusion detection to detect DoS attacks
• Intrusion Detection FAQ - Everything you ever wanted to know about intrusion detection
• Snort: The Open Source Network Intrusion Detection System - Snort is a lightweight network intrusion detection system, capable of performing real-time traffic analysis and packet logging on IP networks
• Talisker's Intrusion Detection Systems - This independent site lists every known commercial Intrusion Detection System, plus a few other seasoned campaigners

Mailing Lists

• FireTower - Maintains Raptor firewall mailing list and archives
• Firewalls and Security Mailing List - Sponsored by Great Circle Associates
• Firewalls and Security Mailing List Archive - An Archive of the Firewalls Mailing List
• Firewall Wizard Mailing List - A moderated list for the discussion of network firewall and security issues

Misc. Security Sites

• COAST Library - Several papers on various aspects of network security
• Computer Security Information - Links to general information about computer security including documents, faqs, and newsletters
• Computer Security Institute - Association for training of computer security professionals
• Firewall.cx - Contains a wealth of security and networking resources including guides to firewall topologies and architectures, networking guides, and networking and security downloads (ITPRC "Link of the Week")
• FreeRADIUS.org - An open source implementation of Radius
• Goldy's Network Security Links - collection of links to security information
• Idea Hamster- Home site for the open source security testing methodology manual, which has the distinction of trying to be an open standard for Internet security testing (ITPRC "Link of the Week")
• InfoSysSec - The Security Portal For Information System and Security Professionals
• Infowar.com - Security related information site sponsered by several network security organizations
• IWS - The Information Warfare Site - News, discussions and mailing lists focusing on information security, information operations and e-commerce (ITPRC "Link of the Week")
• OPSEC: Open Platform For Security - Check Point's partnership effort to create end-to-end Internet Security 
• RobertGraham.Com - Various network security publications and FAQ's
• Security Dogs - Information on VPN's, Firewalls, NAT, and QoS
• Security Focus - Provides a wealth of news and information on network security issues. Also hosts the bugtraq mailing list
• Security Pointer - Information on computer security, privacy online, firewalls, with security downloads, guides, tutorials, articles, news, virus alerts, tips
• Security Portal - Provides security related news, downloads, tutorials and papers
• Security Search Engine - Looking for info on network security, you'll find it here
• Things that go bump in the Net - Security White Paper, By IBM
• TNO-FEL's URLography on Security Information - Links to many security resources
• Trinux - Linux Security Toolkit - A Linux security package that can run on 2-3 floppies
• Win2000Security.com - Provides news, resources, and information on Windows 2000 security issues
• WWW Security FAQ - Frequently asked questions on web site security

Virus Information

• Computer Virus Myths home page - Great source of info about viruses and hoaxes
• McAfee Anti-Virus Center - Information on viruses and virus hoaxes.  Also support for McAfee anti-virus products
• Symantec Anti-Virus Center - Up to the minute information on viruses and exploits