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 CompTIA Network+.