Short answer: iPhones often use IPv6 on mobile networks and some Wi-Fi networks. If a VPN handles IPv4 but blocks, ignores, or exposes IPv6 differently, a browser check can show an IPv6 result that does not match what you expected.
IPv6 visibility is not automatically bad. It becomes a leak concern when your privacy goal is to route traffic through a VPN or block unsupported IPv6, but this browser still exposes an unexpected IPv6 path.
Problem
- iOS has no per-interface IPv6 switch, so the result is decided by the VPN profile and the network, not by a phone setting.
- Wi-Fi and cellular reach IPv6 through different operators, so one run describes one network only.
- This reads the browser session. Other iPhone apps can take a different route on the same network.
Run the test
Start with IPv6 Leak Test. Keep the same browser and network when comparing before and after.
- Open IPv6 Leak Test on the iPhone browser you use for the session.
- Run once on Wi-Fi with the VPN disconnected, then connect the VPN and rerun.
- Repeat on mobile data if the issue only appears away from Wi-Fi.
- Compare What Is My IP, DNS Leak Test, and VPN Leak Test if IPv6 visibility changes.
- Use Safe Copy after the final run so the result can be saved without raw IP values.
How to read the iPhone IPv6 Leak Test result
| Result | Usually means | What to do next |
|---|---|---|
| IPv6 not reachable | The browser did not expose a reachable IPv6 path in this run. | This can be normal if network or VPN blocks IPv6. |
| IPv6 visible and expected | The network or VPN supports IPv6 in this browser session. | Check provider docs if you expect VPN-routed IPv6. |
| IPv6 visible outside VPN expectation | The VPN may not tunnel or block IPv6 as expected. | Review VPN profile, provider IPv6 support, and retest on Wi-Fi/mobile data. |
| Wi-Fi differs from mobile data | Carrier and router IPv6 behavior can differ. | Document the network type in Safe Copy. |
| DNS/IP mismatch | IPv6, DNS, and page IP may not follow the same route. | Run DNS Leak Test and VPN Leak Test together. |
iPhone-specific checks
- Remember that iOS browsers share the iOS browser engine, but profiles, apps, and VPN profiles can still behave differently.
- Compare Wi-Fi and cellular because mobile carriers often handle IPv6 differently.
- Check VPN provider documentation for IPv6 support or blocking behavior.
- Avoid assuming that disabling IPv6 is the only fix. Correct VPN/router handling is usually better.
What to do after the result
iOS gives you no per-interface IPv6 switch, so unlike the desktop pages there is nothing on the phone itself to turn off. The decision belongs to the VPN profile and to the network. Test both before concluding anything: Wi-Fi and cellular reach IPv6 through different operators, and a result that appears only on mobile data is the carrier's dual-stack rather than a fault in the VPN app.
If IPv6 stays reachable on both networks with the VPN connected, the useful question is what the provider documents. Some tunnel IPv6, some block it at the profile, and some are IPv4-only and leave the OS to handle it. All three can produce the reading you are looking at, and only the provider's own documentation separates them. Reinstalling the VPN profile is worth one attempt, because a profile carried across an iOS upgrade can keep rules the current app no longer sets; past that, the answer is with the provider rather than in this browser.
Frequently asked questions
Is IPv6 on iPhone automatically a leak?
No. It is only a leak concern if IPv6 remains visible outside the route you expected.
Why does mobile data differ from Wi-Fi?
Carrier IPv6, Wi-Fi router settings, VPN profiles, and DNS behavior can differ between networks.
Does this test cover every iPhone app?
No. It checks this browser session. Other apps can use different routes.
Limits and methodology
MyIPScan checks show observable browser and network signals for the current session. Results can change with browser profile, app route, VPN server, router, OS, carrier, DNS, and time. See the methodology and editorial policy.