Patent ID: 7290060

Claim:
A network-connecting apparatus for a first private network having a first network device, the apparatus comprising: a direct connection part for providing a direct connection by forming a tunnel with a second private network in response to a connection request from the first network device, said request being a request to connect to a second network device in a second private network, wherein the direct connection part comprises: an address acquisition part for acquiring a public IP address of the second private network from a domain name management server based on a domain name of the second network device received from the first network device, and for acquiring a private IP address of the second network device based on the received domain name, wherein the acquired private IP address is a destination address having a subnet number of the destination address of a packet to be transferred outside the first private network; and a connection management part for connecting to the second private network based on the acquired public IP address and forming the tunnel with the second private network: an address mapping part for converting the acquired public IP address and the acquired private IP address into an address system used in the first private network in case an address system used for the public IP address of the second private network is different from the address system used for the public IP address of the first private network; and an address change part for changing the subnet number of the destination address through the direct connection to a tunnel number allocated to the tunnel, changing a subnet number of an origination address of the packet to the tunnel number, and changing the tunnel number of the destination address to the subnet number of the destination address when the packet is transferred to the second network device.