Research On Packet Filtering Technology In Network Isolating Systems

This paper introduces some related knowledge of network physical isolating tecnology and the isolating card which has the function of package filtering.The card works with isolating controller to build Network isolating system,which using Ethernet switch IC to isolate the two networks.The isolating card uses MCF5271 as CPU,LANglC111 for the network connection with user's computer,and MCF5271's FEC with isolating controller. They can support 10/100Mbps network.The recognition of user's ID is done by special module that uses IC card SLE4442.The isolating card connects with PCI using CH365.This makes the software running on the user's computer can get the status of the isolating card.The network isolating system is mostly to isolate local network and public network,which they needn't exchange data.And user's computer has two HDDs which uses for HDD isolating.The introduction of packet filtering technology strengthen the isolation function,which offers the necessary options for the user to use computer and manage the network.Because of the strong extensibility of the isolation card,it can use for an experimental platform for network safe research.And even using for product research.This paper gives details on the purpose and details of reserach.And also gives details on the isolation card design and debug.