The Design And Implementation Of WLAN Monitoring System

The gradually mature wireless communication technology has released people from complicated and overloaded network cabling. The highly popular Wireless Local Area Network(WLAN) is used everywhere in our daily lives, therefore, with that come the indispensible demand of network management and monitoring. On the one hand, WLAN can provide convenient services for normal users, and it is very likely to be used as a tool for criminal purpose by some malevolent people due to technical vulnerabilities, e.g., network attack, stealing privacy information and spreading rumors of endangering national security, etc. On the other hand, to network-supervision departments, secret services and some companies, it’s essential for them to guarantee the internal WLAN well regulated.Based on the above requirements, we have researched and developed an easy-to-use and fully functioning integrated management system of WLAN, with the functions of scanning and positioning wireless AP, disconnecting suspicious user stations from AP, collecting and parsing online data, and recovering password.The main work of this thesis includes the following parts:Firstly, the thesis respectively introduces the subject background, research objectives, research significance and research situation at home and abroad. Related knowledge is elaborated, e.g., WLAN network structure, WLAN frame format, encryption mechanism, and the functions of AirPcap tool suite involved in the subject are illustrated in detail.Secondly, after a better understanding of user demand, the system’s overall framework and the general data flow are raised based on deliberate design, then the specific functions and data flow of each involved module are designed, including the function module of Wi-Fi scanning, AP positioning, data collecting and filtering, data parsing, password recovering, AP disconnecting and data managing, etc.Thirdly, based on the work of part two, further effort is put into implementing each function module, i.e., realizing Wi-Fi scanning function through calling network configuration tool netsh in Windows, realizing AP positioning function of measurement state by using directional antenna and the principle of signal transmission attenuation, realizing data parsing function according to a further understanding of data parsing process, realizing password recovering function through calling aircrack-ng respectively by using “brute-force” method, dictionary method and PTW method, and realizing disconnecting specified AP from STA function through constructing Deauth frame.Lastly, system measurement is conducted in terms of functionality and performance, then summarization and expectation of the study is provided, which mainly point out the existing problems and the further improvement plan of the system. The measurement results show that each functional module operates well and the overall performance is stable.