For testing purposes I tried to create IPv6 network from my Mac. I followed this tutorial: https://developer.apple.com/library/archive/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/UnderstandingandPreparingfortheIPv6Transition/UnderstandingandPreparingfortheIPv6Transition.html
Except one thing. Instead of Thunderbolt Ethernet I used only Ethernet. WiFi was successfully created and I am able to use it.
However it seems, that the created WiFi is still not IPv6. I ran this test: http://ipv6-test.com and in results it says Not supported under IPv6 connectivity
What is the problem? Why is my network still IPv4? How can I create proper IPv6 network?
The NAT64 test network that Apple advises you to create does not provide global IPv6 connectivity. It provides only local IPv6 connectivity between your iOS device connected to the WiFi access point and your Mac. The Mac then uses NAT64/DNS64 to send any Internet traffic via IPv4 (which is similar to what some mobile carriers do). This is why an IPv6 testing website shows you that IPv6 is not supported.
The purpose of this setup is to test IPv6 compatibility of your iOS applications on a physical device. You may download an iOS app which will show whether your device is correctly obtaining an IPv6 address from your Mac (because iOS doesn't natively show this info).