Enterprise Mail System Security Research Based On Protocol Analysis

With the rapid prevalence of Internet, people are accustomed to search for information in it. But there is plenty of dangerous information in the network, which has brought out so many insecurity factors to us.As for the enterprise, constructs the secure network is becoming the most important demand. There is huge network traffic flowing in Internet that it is necessary to monitor and control the traffic which contains not only common information but also bad or illegal information. But traditional sniffing technology can be only worked well in Ethernet, which restrict the usage of sniffing badly.This thesis designed and implements a remote packet sniffing model based on well studying and analyzing the technology of network sniffing and protocol analysis. The system can work in WAN (Wide Area Network) and analyze network packets flexibly and powerfully.This thesis primarily focuses on the following:(1) Protocol analysis technology in term of modularization. Protocol analysis, the reverse procedure of data encapsulation, can show the true meaning of captured packet.(2) High performance network sniffing and packet capture technology. This is the foundation of network security and this new technology. This thesis puts forward a new remote packet sniffing technology based on the traditional one.This thesis designs and implements a new remote network sniffing model which can work in WAN and do protocol analysis with packets in according to some designing principles and discussing some key technologies in detail.