IPSec enables companies to build VPNs and other Internet-centered mission-critical applications with confidence that their data will remain secure. IPSec, Second Edition is the most authoritative, comprehensive, accessible, and up-to-date guide to IPSec technology. In this book, two leading authorities in IPSec standardization and implementation cover every facet of IPSec architecture and deployment -- and present detailed case studies that demonstrate how IPSec can be used to provide end-to-end security in real business environments. The authors lay the groundwork for understanding IPSec with a concise review of the relevant fundamentals of cryptography and TCP/IP networking. Next, they introduce IPSec's architecture and components, including its Encapsulating Security Payload (ESP), Authenticated Header (AH), Internet Key Exchange, IPSec modes, security associations, processing, and ICMP-related issues. IPSec, Second Edition contains detailed coverage of deployment issues, including policy definition, representation, distribution, and management; implementation architectures; and extensive case examples of IPSec usage in the real world. For every networking professional interested in Internet security -- not just security specialists!