Marcus Ranum is CEO of Network Flight Recorder, Inc., and has been specializing in Internet security since he built the first commercial firewall product in 1989. He has acted as chief architect and implementor of several other notable security systems including the TIS firewall tool kit, TIS Gauntlet firewall, whitehouse.gov, and the Network Flight Recorder. Marcus frequently lectures on Internet security issues, and is co-author of the "Web Site Security Source book" with Avi Rubin and Dan Geer, published by John Wiley and sons.