Patent ID: 7143188
Filing Date: 2006-11-28
Classification: H04L

Abstract:
1. A method for Network Address Translation (NAT) integration with an Authentication Header (AH) protected packet, comprising: providing a client computer with a public address from a NAT gateway computer; forming the AH protected packet by the client computer with the public address as the source address; sending the AH protected packet from the client computer to the NAT gateway computer together with an initiator indicator and a medium access control field; checking by the NAT gateway computer whether the source address is from a plurality of public addresses available at the NAT gateway computer; in response to the source address being from the plurality of public addresses, transmitting the AH protected packet from the NAT gateway computer to a remote computer foregoing address translation of the source address; recording a local address of the client computer in a mapping table at the gateway computer in association with an initiator indicator and the medium access control field with an indication in the mapping table that an AH security protocol is selected for the incoming traffic and a time stamp for the start of the incoming traffic to establish secure communication between the client computer and the remote computer so that the gateway can determine which client computer receives return traffic; and in response to not finding a security parameter index in the mapping table or not matching the initiator indicator with an entry in the mapping table upon receiving return traffic from the remote computer, not routing the packet of the return traffic to the client computer.