本书系统介绍了虚拟专用网的概念、起源、配置、实现和维护，还对虚拟专用网体系结构、加密工具、有关限制、防火墙结构等内容进行了探讨，并提供了大量实例。本书是网络、MIS管理员必备的参考书。

-This book introduces the concept of a virtual private network, origin, configuration, implementation and maintenance, but also on a virtual private network architecture, encryption tools, such restrictions, firewall architecture, etc. were discussed, and provides a large number of examples. This book is a network, MIS administrator essential reference book.