NAT64 provides a way to transition to IPv6 while you still need to communicate with IPv4 networks. When you need to communicate from an IPv6-only network to an IPv4 network, you use NAT64 to translate source and destination addresses from IPv6 to IPv4 and vice versa. NAT64 allows IPv6 clients to access IPv4 servers and allows IPv4 clients to access IPv6 servers. You should understand NAT before configuring NAT64.