Wireless Lan Monitoring System

WLAN has been widely used because of its advantages of high meeting speed, convenience of setup and facility of constructing, and it is the trend in network developing. The opening of wireless wave makes the sniffing arm at WLAN much easier, and the security of WLAN faces the terrible challenge.WLAN sniffer is the basement of WLAN monitor and control and it can produce evidence of network crime. The traditional WLAN sniffer is mainly based on share mode, and data analyse limits to transport layer, the result are difficult to analyse. Information reverting can analyse packets on application layer, recombine packets and revert the file according to application protocols, in order to produce convenience to information censor.This paper combines the WLAN sniffer and the information reverting techniques and implements a system which can sniffe and rever WLAN communications. The system has two purposes: One is that the network administrators can use it to control network information and watch network flow; the other is that it can produce evidence of network crime. In addition, WLAN sniffer system can also integrate with the monitor agent platform to remote sniff the WLAN communication.The system adopts man-in-the-middle attack idea and improves the switch WLAN sniffer and the efficiency of packet capture and analyse using multithreading and multi-buffer techniques. The researches including:1. WLAN sniffer. Sniffer method under switch local area network and man-in-the-middle accack technique in WLAN are studied in this paper.2. Information analyzing and reverting. The meaning and the development of information security are discussed in the paper and the information capture and reverting are also deeply studied. The researches emphasizes on the information analyzing and reverting techniques which based on FTP and HTTP protocols and it also illustrates the process of imformation revert by an example of file transmission in passive mode of FTP.3. System implements. This system can either be used independent or be integrated to the existing system through appropriate interface. The monitor agent based system implement is the emphasis of the paper.