Research And Realization Of Monitor System About Hosts In LAN Accessing Network

Internet has become the broadest information resource. Every Internet user may querythe information what he want to know. But except many very available information,lots ofunfit information just as violent,eroticism information or the behaviors of attacking LAN areexist. How to supervise the behaviors of network-host and manage LAN effectively to restrictusers' behaviors has become a very important thing. We start with the LAN sniffer andanalyze the present technology of sniffer. Furthermore we resolve how to capture data packetsfrom data-link layer with the circumstances of switch network. And complete the constructionof this system about monitoring network.Firstly we introduce the conception, principle and technology of network sniffer simply.Subsequently discuss the mechanism of data packets capture and configuration of Libpcapand WinPcap with detail. And research the contents of data filter and read-write processprofoundly. Finally we expound the request analysis and system design with detail. Moreovercomplete partial functions of this system and give some strategies to settle down the questionof losing data packets in order to enhancing the performance of this system.