Abstract—In the mobility environment, the interoperability between IPv4 and IPv6 networks is required due to the incompatibility that occurred in the headers of both IPv4 and IPv6 protocols. It is probable that a Mobile Node (MN) moves out of its home agent’s domain towards a different IP domain IPv4/IPv6. This paper proposes a new scheme for mobile nodes that are connected with the home agent which is basically located behind Network Address Translation (NAT) to allow roaming of the MN throughout the IPv6 domains. MN would be able to communicate with its home agent despite its roaming throughout the IPv6 domain. Therefore, the proposed scheme is based on Teredo tunnel that allows clients behind NAT to utilize and get IPv6 services.