NAT64 works fine if you have an ipv6 client and want to talk to ipv6. That's just regular old network address translation. But if your server is on ipv6, NAT6

NAT64 works fine if you have an ipv6 client and want to talk to ipv6. That's just regular old network address translation. But if your server is on ipv6, NAT64 still needs an ipv4 address so that people there can get to you. The ipv6 address is pointless-- it's easier just to put your server on ipv4 and not mess with NAT64 or ipv6.