Patent ID: 8559448
Filing Date: 2013-10-15
Classification: H04L

Abstract:
1. A method of enabling communication of data packets between a first communications device in a first local network and a second communications device in a second local network, wherein private IP addresses are used for devices present in the first and second local networks which are potentially overlapping in the first and second local networks, comprising the following steps executed in a first gateway of the first network: updating a Local Name Server record, in the first gateway, with a domain name and an IP address of a second gateway of the second network, each of said first and second gateways having a local DNS function; receiving from the first communications device an outgoing DNS request referring to a hostname of the second communications device; determining the IP address of a primary DNS being the second gateway, from the local Name Server record based on a domain name in the hostname; sending a DNS request to the second gateway, using the determined IP address; receiving a DNS response from the second gateway and obtaining a current private IP address of the second communications device from the DNS response, wherein the current private IP address is used in the second network for the second communications device; translating the current private IP address of the second communications device to a modified private IP address used in the first local network for the second communications device, wherein the modified private IP address is within an address space defined for a VPN tunnel between the first and second local networks and is separate from an internal IP address space used in the first local network for devices in the first local network; forwarding the DNS response to the first communications device, referring to the modified private IP address of the second communications device; receiving a data packet from the first communications device, said data packet comprising the modified private IP address of the second communications device as destination address; and transmitting to said second gateway said data packet without translating the destination address such that translating the current private IP address of the second communications device to the modified private IP address is performed by the first gateway and converting the modified private IP address back to the current private IP address of the second device is performed by the second gateway.