This paper discusses the network security scanning and some scanning methods which contain port scanning, vulnerability scanning and remote operating system detection are studied. In order to reduce the complexity and get high performance, the architecture of a common network security scanning system based on Libnet and Libpcap is provided and the every module of system is designed and implemented. The key modules include packet constructing, packet sending, packet capture, packet analyzing module and information log analysis module. The methods of packet injection based on Libnet and the pack...