Patent ID: 7366188

Claim:
A gateway comprising: at least one public network interface connected to a public network; at least one private network interface connected to a private network; and a control unit linked to the public network interface and the private network interface, wherein the control unit is configured to set up a virtual private network (VPN) tunnel by communicating with a gateway of a second private network connected to the public network, if a tunnel setup request is received from a host connected to a first private network to set up a tunnel to the second private network, and wherein the control unit is configured to create a new network address table in order for the first and said second private networks to use different network addresses in the VPN tunnel, and translate addresses based on the new network address table and forward data packets transmitted from the host connected to the first private network or from the second private network, if the first and second private networks have the same network address or a network address of one of the first and second private networks is included in a network address of the other one of the first and seconds private networks, wherein the communicating with a gateway comprises sending a tunnel setup request message comprising a network address of the first private network and a second network address to be used in the VPN tunnel as a network address of the first private network.