

Apple to iOS devs: IPv6-only cell service is coming soon, get your apps ready - saidajigumi
http://arstechnica.com/apple/2015/06/apple-to-ios-devs-ipv6-only-cell-service-is-coming-soon-get-your-apps-ready/

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saidajigumi
There's a particularly interesting bit about changes coming with cellular
providers in this article, down at the "What's actually happening" heading. A
snippet:

 _[...] Lakhera referred to the fact that there are pretty much no IPv4
addresses left and that the big cellular carriers really don 't want to
continue running IPv4 and IPv6 side by side in dual stack
configuration—apparently, IPv6-only cellular service is coming. Soon._

 _The way Apple is addressing that situation is to make sure that all iOS apps
support IPv6. However, many servers are still IPv4-only. To reach those, the
cellular networks are going to deploy NAT64 translators. NAT64 allows IPv6
applications to access IPv4 servers. Without these translators, IPv6
applications ask the DNS for IPv6 addresses to connect to, but obviously
IPv4-only servers don 't have IPv6 addresses, so a regular DNS server then
returns an empty list of IPv6 addresses, leaving the application all dressed
up with nowhere to go. A DNS64 server, on the other hand, creates a
"synthetic" IPv6 address that the application can use. The packets sent to
those addresses end up at the NAT64 translator, which recovers the IPv4
address of the intended destination using the IPv6 address created by the
DNS64 and translates the packet from IPv6 to IPv4. [...]_

~~~
p1mrx
IPv6-only + NAT64 networks aren't coming "soon"; T-Mobile has been operating
this configuration on non-Apple devices for the last 1-2 years:

[http://www.internetsociety.org/deploy360/resources/case-
stud...](http://www.internetsociety.org/deploy360/resources/case-study-t-
mobile-us-goes-ipv6-only-using-464xlat/)

Android (and more recently, Windows Phone) uses 464XLAT to keep the AF_INET
socket APIs on life support. Apple didn't like that design, so instead they're
telling app developers to fix their code.

It remains to be seen whether Apple's iron fist can weed out the IPv4-only
apps well enough to satisfy the carriers, or if they'll backpedal and
implement a broader compatibility hack.

