JOHN CHIRILLO is Senior Inter-networking Engineer at ValCom, a technology management company in the Midwest. John holds numerous certifications including CCNA, CCDA, CCNP, CISSP, Intel Certified Solutions Consultant, Compaq ASE Enterprise Storage, and Master UNIX certifications, among others. John has more than ten years of experience on various computer systems and more than five years of training experience. John is the author of five Wiley books, including the Hack Attacks Series.