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iOS 26 / 26.0.1 - No or slow DNS on cellular

Hello,

after I installed iOS 26 on my iPhone 14 Pro, DNS requests for installed NextDNS app in mobile became extremely slow or broke off with timeout. Uninstalling of the app and setting up a NextDNS profile also did not solve the problem.
There were no problems in the WLAN.
Also, a reset of the network settings and a restart of the mobile phone did not bring a solution.

Even after switching to an iPhone 17 Pro, the problem was reproducible. With other DNS profiles, e.g. Mullvad, it works without problems.
Even use without private relay has not brought any improvement.
iOS 26.0.1 also not.

I tested all this in the network of Deutsche Telekom and Vodafone. To my knowledge, both networks rely entirely on IPv6.
My landline is also natively IPv6, but the problem does not occur in the WLAN via it.

The issue does not occur on an iPhone 13 Pro with iOS 18.x.

Is anything known that Apple has changed anything in the current versions that can trigger this behavior? And if so, how can I solve the problem?

Greeting
Wutti

7 replies

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    • wutti
    • 5 mths ago
    • Reported - view

    Ok, if I try the check on ping.nextdns.io without any profile in cellular network of Telekom Germany, there are only errors.

    So option 1, Telekom and Vodafone blocks NextDNS, option 2 Apple blocks NextDNS. But with activated Private Relay, there are the errors in the check. Without Private Relay there is a blank site on ping.nextdns.io.
     

    I‘m very confused

    • wutti
    • 5 mths ago
    • Reported - view

    ok, I found the error. Using the standard APN settings for Deutsche Telekom mobile on iPhone with iOS26 uses IPv6 only.

    After switching the APN settings to IPv4, DNS over NextDNS works without problems.

    But... This is only a workaround. IPv4 is not a solution. So NextDNS should check why IPv6 isn't working and fix this problem.

    • wutti
    • 5 mths ago
    • Reported - view

    But it‘s curious that the IPv6 connection problem is not available on landline. Only on cellular. 

    • wutti
    • 5 mths ago
    • Reported - view

    No one else with this problem? And no idea from the developers?

    • wutti
    • 5 mths ago
    • Reported - view

    Ok, next new information. Activated Private Relay with generic location instead of country and timezone and APN internet.v6.telekom works.

    Spooky

    • Martin.30
    • 11 hrs ago
    • Reported - view

    Similar problem here.
    Also the same configuration, but APN internet.telekom (IPv6) behaves the same as APN  internet.v4.telekom (IPv4).
     

    On iPhone (iOS 26.4):
    The first page load in Safari takes up to 10 seconds.
    Subsequent page loads are fast.
    First page loads in brave or edge are fast immediately.
    First page loads in Safari with a manually created profile are fast, too.

    On MacBook Air (MacOS 26.4):
    Page loads are fast, no impact at all.

    It seems that it's only slow in the browser-engine and in apps that use the browser-engine (e.g. NetNewsWire).
    Apps itself load content fast.

     could you check if it's similar behaviour at your side ?

    • Martin.30
    • 9 hrs ago
    • Reported - view

    To compare the behaviour i just created a controld test-account.
    I wanted to cross-check if it might conflict with iOS.
    Using APN internet.telekom (IPv6).

    On iPhone (iOS 26.4):
    The first page load in Safari loads immediately.

    The rest of the tests results are identically.

     Do we have a known issue here ?

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Content aside

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  • 9 hrs agoLast active
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