BOB TOXEN has 28 years of UNIX/Linux experience. One of the 162 recognized developers of Berkeley UNIX, he learned about security as a student at UC Berkeley, where he cracked several of the original UNIX systems there. He is now President of Fly-By-Day Consulting, specializing in Linux and network security, firewalls, VPNs, 24x7 network monitoring, response, and administration for clients worldwide. In 2002, his recommendations were included in a report on improving U.S. intelligence that was presented to President Bush at the President's request. Toxen currently works with the U.S. Centers for Disease Control and Prevention to combat bioterrorism.