本文从提高局域网络的安全出发，提出了具有主动防御功能的Intranet 网的概念，并 就主动防御Intranet 网的组成、工作原理、工作过程及实现方法进行了阐述，最后，对主动防御网的关键部件及技术进行了探讨。关键词：主动防御；网络安全；入侵检测Abstract: The conception of intranet for proactive defence from improving intranet security. Composing and work principium and process and realizing method are expatiated. Finally, Key components and technology are being discussed.Key words: proactive defence; network security; intrusion detection