Design And Implementation Of Application Reverting System For Multi-protocols

Along with the popularization and widely used of the Internet, the volume of information takes not only great convenience but also security threat to human's lives. The matters that some staffs betray confidential matters are usually happened, and have brought tremendous losing to the enterprises. Currently, people let out the secrets of their company mostly utilize the email and uploading information to HTTP on the network. So, it is necessary to capture and revert the data traffic of the email and the information on BBS, message board and chat room through the enterprise network in order to monitor the sensitive content.The thesis focuses on the study and implementation of the reverting technology for the application protocols, such as POP3, SMTP and HTTP POST. The main contributions are as follows.This paper analyzed some normal ways of capture packets. Based on the characteristic and needs of the system, it took the WinPcap as the capture tools of the network interface. Utilizing the function of Libnids capturing packets and the BPF filtrating rules, the system could deal with 10~6B/s traffic in the networkBased on summarizing the protocols of POP3, SMTP, and the POST request of HTTP, this paper studied and solved the key problems in the process of email distributing as well as POST request distilling and decoding.This paper compared two different HASH algorithms, and proved that CRC-32 is the better one for the throughput speed above 100Mbps in the applications.Utilizing Libnids function of reforming the TCP data stream, this paper researched and implemented Application Reverting System for Multi-protocols.The system implement on layered structure, so it could be extended the functions by adding the reverting modules for other TCP application protocols, such as FTP and TELNET.