NAT64: Facilitating IPv6-IPv4 Communication

 NAT64

NAT64, which stands for Network Address Translation 64, is a technology that allows IPv6-only clients to communicate with IPv4-only servers by translating IPv6 packets into IPv4 packets, essentially bridging the gap between the two IP versions and facilitating a smooth transition to IPv6 while still accessing older IPv4 services; it is often used in conjunction with DNS64 to automatically resolve IPv4 addresses to synthetic IPv6 addresses for seamless connection establishment.

Key points about NAT64

• Functionality: When an IPv6 client tries to connect to an IPv4 server, the NAT64 device takes the IPv6 packet, extracts the necessary information, and translates it into an IPv4 packet with a designated IPv4 address, allowing the connection to be established to the IPv4 server.
• Translation process: The translation primarily involves modifying the IP header and replacing the IPv6 source address with a designated IPv4 address from a pool managed by the NAT64 device.
• DNS64 integration: To simplify the process for users, NAT64 is often paired with DNS64, a DNS extension that automatically returns a synthetic IPv6 address for an IPv4-only domain name. This enables the client to initiate connections without needing to translate addresses manually.

Use cases

• IPv6 transition: For organizations migrating to IPv6, NAT64 allows existing IPv4 services to remain accessible to new IPv6 clients.
• Internet access: When an IPv6-only network must reach public IPv4 servers on the internet.

Limitations:

• Performance impact: NAT64 can introduce latency due to the additional translation step required for each packet.
• Security concerns: Improper configuration can potentially expose vulnerabilities related to address translation.

How NAT64 works

• Client request: An IPv6 client sends a packet to an IPv4 server address.
• NAT64 translation: The NAT64 device receives the IPv6 packet and translates the source IPv6 address to a designated IPv4 address from its pool.
• Forwarding: The translated IPv4 packet is then forwarded to the intended IPv4 server.
• Response: The response from the IPv4 server is translated back to IPv6 by the NAT64 device and sent to the original IPv6 client.

This is covered in Network+.