NAT64NAT46

NAT64NAT46 is a network transition mechanism that allows IPv6-only hosts to communicate with IPv4-only hosts. It is a combination of two related technologies: NAT64 and DNS64. NAT64 is a stateful translation mechanism that translates IPv6 packets from IPv6-only clients into IPv4 packets destined for IPv4-only servers. Conversely, it translates IPv4 packets from IPv4-only servers back into IPv6 packets for IPv6-only clients. DNS64 is a DNS server that synthesizes AAAA records (for IPv6) from A records (for IPv4). When an IPv6-only client queries DNS for an IPv4-only host, DNS64 returns a specially crafted IPv6 address. This address, when used by the client, is routed to a NAT64 translator. The NAT64 translator then performs the actual packet translation.

The primary purpose of NAT64NAT46 is to facilitate the transition from IPv4 to IPv6. As IPv4 addresses become scarce, networks are increasingly migrating to IPv6. However, not all devices and networks can immediately support IPv6. NAT64NAT46 provides a way for IPv6-only clients to access existing IPv4 resources without requiring every network element to be upgraded to IPv6 simultaneously. This approach offers backward compatibility during the prolonged transition period. It is typically deployed at network edges, such as at the border between an IPv6-only network and the IPv4 internet. The effectiveness of NAT64NAT46 relies on the accurate synthesis of IPv6 addresses by DNS64 and the efficient translation by NAT64.