DNS64DNSv6

DNS64 is a DNS64 server technique used to enable IPv6-only hosts to access IPv4-only resources. It works by intercepting DNS queries for IPv4 addresses that are not directly resolvable on the IPv6 network. When a query for an IPv4 address is received, the DNS64 server synthesizes an IPv6 address from the IPv4 address. This synthesized IPv6 address is then returned to the client. This synthesized address typically has a specific prefix, known as the "well-known prefix," which indicates that it is an IPv4-translated address.

The DNS64 server then relies on a NAT64 (Network Address Translation 64) translator to map the synthesized IPv6 address back to the original IPv4 address. When the IPv6-only host attempts to communicate with the synthesized IPv6 address, the NAT64 device intercepts the traffic, performs the address translation, and forwards the packet to the IPv4-only destination. The return traffic from the IPv4-only host is similarly translated back to the IPv6 address by the NAT64 device before being sent to the IPv6-only client.

DNS64 is a crucial component in facilitating IPv6 adoption by providing a backward-compatible mechanism for accessing existing IPv4 content and services. It is often deployed in conjunction with NAT64 in dual-stack transition environments where complete IPv6 deployment is not yet feasible.