Matthew G. Marsh, founder and president of Paktronix LLC. has been working in network architecture for the last 18 years, and working with Linux networking specifically since 1993. He is the Chief Scientist of the Nebraska CERT working with IBM, US Strategic Command, the FBI and other groups on IPv4 security structures and routing. He developed the only policy routing firewall system for Linux available under the GPL, and an IPSec VPN solution using policy routing structures under Linux. Currently he is actively researching Linux security on the IBM OS/390 as well as the implementation of IPv6 on Linux and the OS/390.