NAT64

• Transition technique designed to allow native IPv6 hosts to access IPv4-only content.
  • (Translation technique not a tunneling technique).
• Primarily used to allow v6 hosts to initiate connections to IPv4 content.
  • Mechanisms do exist to allow the reverse.
• Stateful and stateless versions.
  • stateful can use any prefix
  • stateless has restriction on prefix

NAT64 and DNS64 co-existance.

1. IPv6 host sends AAAA DNS Query
2. DNS64 server tries AAAA lookup and fails
3. DNS64 server successfully resolves IPv4 address
4. DNS64 server generates AAAA DNS response of <IPv6 prefix:IPv4 adress> and sends it back to the client.

• A specific IPv6 prefix must be allocated to represent addresses that will be translated by NAT64
• There are two names:
  • Well-known prefix:   64::ff9b::/96    (not routable)
  • Network Specific prefix ( NSP ) derived from global IPv6 Prefix