With the popularization of network technology and application, the network security problems are becoming more and more obvious. The attack mode of hackers is changed from the former exploit based on TCP / IP to the exploit and invasion based on operating system and application software. For example, hackers can enter the internal network through the legal port opened by the firewall, causing huge losses to the users. The worm virus and Trojan can enter the internal network through the legitimate ports opened by the firewall, causing the network to be paralyzed. Malicious programs such as spyware can be opened through the firewall Legitimate port into the internal network, stealing commercial secrets.

Security threats are not only from the outside, inappropriate Internet access within the enterprise, abuse of the Internet and theft, but also security issues. According to IDC, 60% of security losses are caused by internal business reasons, while inappropriate resource utilization and employee online behavior are often the "culprits." For example: Web browsing, BT download, IM real-time communication, P2P file sharing and other activities. Improper resource utilization and employee online behavior have brought spyware, malicious programs and computer viruses, resulting in a series of security problems such as the depletion of enterprise network resources, the leakage of confidential information and the proliferation of intranet viruses.