The System Of Network Isolation Based On Mcf5271

Since January 1^st 2000, our country put the "Computer Information system International Networking Security Management Stipulation" which was promulgated by NSA into practice. The sixth of the second chapter of the stipulation illuminated that the computer system involved in country confidential cannot be connected to Internet or other public network directly or indirectly and it must be isolated in physical methods. Many companies which demanded security requested their network equipments to be isolated separately in physical methods. The network is widely using many kinds of complex software technology, such as the firewall, the agent server, the intrusion detection, the mechanism of channel controlling and so on, but because these technologies all are based on the software protection which are only logical mechanisms, cannot fulfil the above requirements.At present many network shielding systems are based on the pattern of the switching of the relay electric circuit. With the rapidly increasing of the network, this kind of system which cannot work under the 100M network condition has not been suitable.This article developed one kind of network shielding system. The system can work under the 100M network condition and isolate different networks.The network shielding system has two parts. One is the client which completes status recognition, the switching of the hard disk and data communication with the switching central point. The other is the switching central point, which inspects the connection state of the client, exchanges the order with the client, performs order from the client and controls the network chip. The latter part is designed by the author.The author used Mcf5271 which was a series of ColdFire as the...