Patent ID: 8665873

Claim:
An apparatus comprising: a home agent (HA) configured to: couple to an Internet Protocol (IP) version six (IPv6) only mobile node (MN), a network address translation (NAT) server, and an IP version four (IPv4) only host; associate an IPv6 address for an interface with the MN with an IPv4 address for an interface with the IPv4 only host in a NAT state table entry, wherein the NAT state table entry is linked to a binding cache entry (BCE) for the MN that maps an address of the MN to a care-of-address (CoA) associated with the MN; set an IPv6 only flag in the BCE to indicate the MN is an IPv6 only MN; and send a plurality of keepalive messages based on a determined keepalive interval to the NAT server on behalf of the MN to refresh the NAT state table entry that is associated with the BCE for the MN, wherein the NAT state table entry is used to translate an IPv6 packet associated with the MN to an IPv4 packet associated with the IPv4 only host.