Book excerpt: Security+ Guide to Network Security Fundamentals provides a comprehensive overview of network security. Written to map to CompTIA's Security+ Certification Exam, the book is broken down into five sections. General Security Concepts covers authentication methods along with common network attacks and how to safeguard against them. Communication Security includes remote access, e-mail, the Web, directory and file transfer, and wireless data. Infrastructure Security explores various network devices and media, and the proper use of perimeter topologies such as DMZs, Extranets, and Intranets to establish network security. Cryptography basics are provided, including the differences between asymmetric and symmetric algorithms, and the different types of PKI certificates and their usage. Operational/Organizational Security is discussed as it relates to Physical security, Disaster Recovery, and Business Continuity, as well as coverage of Computer Forensics and how it relates to further avenues of specialization for the security student.