What does NAT64 mean?
NAT64 is a transition tool for IPv4 and IPv6 network addresses. NAT64 creates mapping between both address types. It is useful in moving from the IPv4 address set, which is quickly being exhausted, to the larger IPv6 address set.
Techopedia explains NAT64
The problem is that IPv6, developed to add new address opportunities for a burgeoning Web, is simply not backward compatible with IPv4. To that end, the Internet Engineering Task Force (IETF) and other groups have been looking at ways to address the issue. NAT64 is one of them.
In the NAT64 gateway, two interfaces are connected to the IPV for an IPv6 network. Traffic from IPv6 goes through the gateway, which transfers and translates data packets. Although NAT64 is an effective gateway for these two network types, some technologies such as Skype and other types of real-time interfacing are not supported.