问题
Apple's iOS App Store review process now includes a requirement that apps should work on IPv6 only networks.
With that in mind, is Apple defaulting to IPv6-only, on an app-by-app basis, for iPhones connected over mobile networks in the real world (not just in review)?
I.e. is Apple now forcing the move to IPv6-only in the real world for apps that pass it's IPv6 review?
(Any answer to the above question(s) would be great by itself, but for those with in-depth knowledge, a follow-up: Would UDP packets be properly routed to/from an IPv6 mobile device to an IPv4 server via NAT64 on the cellular network? It's actually this concern that leads me to the original question, I'm wondering if TURN clients are using TCP instead of UDP because UDP is not making it through IPv6->NAT64->IPv4).
回答1:
Apple is not forcing IPv6 only support, but they have to adapt to what's happening in the world. More and more mobile networks deploy NAT64 and if apps on Apple would not work on those networks then that could give Apple a bad reputation. Therefore they require that apps support such a network.
There are still apps in the app store that have been uploaded before the IPv6 requirement was in place so they may be broken. At the moment those apps are allowed to stay in the app store, but in the future they might be kicked out. Last time I asked Apple hadn't decided over that yet.
UDP should work through NAT64, but it will be implementation dependent how long ports will remain open etc. That will depend on the network, not on Apple.
来源：https://stackoverflow.com/questions/37974044/is-apple-ios-defaulting-to-ipv6-only-on-an-app-by-app-basis-in-the-real-world