The information regarding computer network management is very complicated and its range is quite wide , too.ln this case,it must be easy to cause loopholes and the secunty of the information regarding computer network management is certarn to be imperilled. In order to develop network software products.it is usually necessary to investigate the internal data structures of network protocols within several switch boards. A method to perform listening in network and keeping useful information ,and how to complete the program using MFC Socket under Visual C++6.0 environment is presented in this paper.