毕业设计：简述局域网监听系统的原理和设计（终稿）.doc

简述局域网监听系统的原理和设计 摘 要 随着计算机网络技术的迅速发展，网络的安全问题也显得越发重要。网络监听技术是系统安全领域内一个非常敏感的话题，也是一项重要的技术，具有很强的现实应用背景。网络监听是网络监测、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。网络监听工具通过网络传输介质的共享特性实现抓包，获得当前网络的使用状况，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；同时也让黑客截获本网段的一些敏感信息，威胁网络安全。 数据包捕获技术是设计网络分析软件的基础，而WinPcap则是Windows系统中实现的一个优秀的包捕获架构。文中结合该软件包的结构与功能对包捕获原理进行了详细的分析，并介绍了其在网络安全监控系统中的应用。该系统的基本原理是通过调用WinPcap库捕获本地网络上的所有数据包，然后对数据包进行协议分析，从而可以实时地监控网络。 关键词：网络监听；WinPcap；包捕获；协议分析 Design and Implementation of Network Sniffing System in LAN Abstract With the rapid development and extensive application of computer network technology, the security problem of network becomes more important. Network sniffer is an important issue and technique in the domain of system security, so it has strong realism application background. Network sniffer is a way which is used in network monitor, load analysis; at the same time it is also a way which is used by hacker to get the information illegally. Network sniffer tools snap packets to get the network’s current status by the shared characteristic of the network transmission medium. It provides a useful tool for network manager which can help them inspect and analyze the information of network; simultaneously hackers also get some important information, so threaten system security. Packet capturing technology is the basis for designing analyzing software. WinPcap is one of the excellent packet capturing architectures under Windows. This paper analyzes packet capturing principle in detail combined with the structure and functions of the software and introduces its application in designing a network security and watch system. The fundamental principle of this system is to capture all packets of the local network using WinPcap library, and perform protocol analyzing and decoding on these packets, so can monitor the network on real-time and find its problem and alarm automatically. The result from the application in LAN also confirms that the system is steady and very effective. Key words：Network S