Design And Implementation Of Network Sniffer Based On WinPcap

With the rapid development of the information age, the business scope provided byInternet is more and more wide, which from simple information access to online trading, theuser information on Internet is very large. Now with TCP/IP protocol, which is themainstream of internet protocol, the network appears a lot of security problems. Therefore,while the network brings people more and more convenient services, people began to paymore attention to the safety of Internet. This makes the Internet security has become a urgentproblem to be solved. And then Network sniffer created, it as an indispensable tool of networktraffic monitoring and fault detection, has become an important field of the computerprofessional.Network sniffer has a strong ability to collect data, it plays a very important role in boththe network security and hacker attacks. It can effectively detect the network packet thattransferred on Internet, and it can effectively support the network security by analysis andutilization. When we deal with our own network problems, through information received bysniffer, we can determine where the cause of the problem is.This research based on a good understanding on each packet structure of TCP/IP protocol.In the design process, we will divide the entire program into three sub module: networksniffer Settings, network packet capture and packet analysis and display, we analysis anddesign each module detailed algorithm.In this process, we use object-oriented c++to realize, and we use MFC, multithreadingtechnology. According to the sniffer realization principle, we sequence realize the networkadapter information acquisition, open network equipment, set up and compile filter, capturingpackets and read offline data packet. We do every step of the concrete realization and finallywe realize the network sniffer based on WinPcap in the Windows platform. Over the coursestudy, we solve the problems, which include packet capture and analysis at the same time,cross thread calls main window control and packet_next_ex function captured header andpkt_data pointer followed the post message appears address error and other important issues.The network sniffer tools in this development can filter the packet according to protocol type, port, address information, we use the multithreading to implement, and realize thefriendly interface. We completed the research purpose. The network sniffer that we design candisplay the packet that we captured in detail, and makes the corresponding analysis andstatistics based on the details.