As information technology is widely used in colleges and universities,the security of network on campus is more and more important.However,in traditional campus network,people always focus more on the exit than the inner access.A number of network security devices are set up at the exit of the network,such as firewall,IDS,Flow Control devices,while the security of inner access is always being ignored.Almost 90 percent of campus network security affairs come from the campus.Partial paralysis of the network h...