Network security issues came from traditional network, wireless network and cloud computing environment. Large-scale cloud computing, versatility and virtualization features of network security had become a hidden threat source. This paper analyzed the sources of network security threats, and established a network security model which encompasses all types of currently known network security factors; it could provide countermeasures to ensure network security. The security model had capabilities of real-time detection, rapid response, immediate recovery, and interaction between various independent modules. The security model used such security technologies as firewall, intrusion detection, intrusion deception, security scanning and PKI.
