Bill Pennington, (CISSP), is a Principal Security Consultant with Guardent Inc. Bill has five years of professional experience in information security, ten in information technology. He is familiar with Linux, Solaris, Windows, and OpenBSD, and is a Certified Information Security Systems Practitioner, Certified Cisco Network Administrator (CCNA), Certified Internet Security Specialist (CISS), and a Microsoft Certified Product Specialist, Windows NT 4.0. He has broad experience in computer forensics, installing and maintaining VPNs, Cisco Pix firewalls, IDS, and in monitoring systems. Bill was a contributing author to several chapters of the original Hacker’s Challenge.