网络信息侦听是网络监测、负载分析等管理活动常用的方法,同时也是黑客非法窃取信息的手段。文章通过分析网络传输介质的共享特性,讨论了侦听系统在Windows下的实现,BPF结构及如何对其性能进行优化,为网络管理员对网络中的信息进行实时的监测、分析提供一个合适的工具,并探讨如何避免黑客利用侦听方式对网络进行攻击。 Network information snooping is a commonly used method for network monitoring, load analysis and other management activities. It is also a means by which hackers illegally steal information. By analyzing the sharing characteristics of network transmission media, this paper discusses the implementation of listening system under Windows, the structure of BPF and how to optimize its performance so as to provide network administrators with real-time monitoring of the information in the network and provide a suitable Tools, and discuss how to prevent hackers using snooping attacks on the network.