Patent ID: 8732817

Claim:
A switching hub connected to terminals, comprising: a control unit configured to connect the terminals to a first network or a second network, a terminal with sufficient security level being connected to the first network and a terminal with insufficient security level being connected to the second network isolated from the first network; and a packet processing unit configured to restrict a communication between the terminals within the second network, wherein the packet processing unit determines whether a packet is for the communication between the terminals within the second network based on a source address and a destination address of the packet, and if the packet is for the communication between the terminals within the second network, then the packet processing unit drops the packet for the communication, wherein the packet processing unit comprises a list memory configured to register a list including an address of a terminal connected to the first network, and the packet processing unit compares the source address and the destination address of the packet with an address registered in the list, and wherein if the source address is not registered in the list and the destination address is not the address of a management server, then the packet processing unit recognizes that the packet is for the communication between the terminals within the second network, and if the source address is registered in the list or the destination address is the address of the management server, then the packet processing unit recognizes that the packet is not for the communication between the terminals within the second network.