Clarke, Glen: - Glen E. Clarke, CompTIA Security+, CompTIA PenTest+(TM), CCT(R), CCNA(R), MCITP, MCT, CEH(TM), CHFI(TM), CISSO, is a technical trainer and owner of DC Advanced Technology Training, an IT training company based in Atlantic Canada. He is the author of CCT/CCNA Routing and Switching All-In-One Exam Guide and CompTIA Network+ Certification Study Guide, both from McGraw Hill. Glen has also authored a number of For Dummies certification titles including the CompTIA PenTest+ Certification for Dummies.