Android IPv6 issues: In my case, an Android driver bug was the reason

[astronaut]

Hi,

there are numerous posts on Android IPv6 issues (lost access, lost gateway, timeout issues etc.) in the OPNsense forum:

https://forum.opnsense.org/index.php?topic=51298.msg262792#msg262792

https://forum.opnsense.org/index.php?topic=43034.msg213764#msg213764

https://forum.opnsense.org/index.php?topic=53043.0

There is an extensive how-to from meyerguru on IPv6 topics in general:

https://forum.opnsense.org/index.php?topic=45822.0

I myself was plagued from annoying IPv6 issues on my Android smartphone (the only Android device in my network) for some time: My device lost its IPv6 connection after some time, and some apps didn't work or timed out. A new connection (e. g. by turning WiFi off/on) solved this issue temporarily. All other operating systems (iOS, Linux, Windows, FreeBSD) are working normally. After having read the above posts, I blamed OPNsense and/or FreeBSD for these issues. I tried a lot of different things to solve this on the OPNsense side, with no success. Turns out this was wrong, in my case, it was an Android driver issue.

My Android device is a Fairphone 6. I found a thread in the Fairphone forum where a lot of users complained about IPv6 issues:

https://forum.fairphone.com/t/dns-over-tls-ipv6-issues-apps-dont-load-data-over-wifi/130519/542

It's a very long thread, but the issues seem at least similar to what I have read in the OPNsense forum posts. It seems that there is an issue with the Android WiFi driver:

https://github.com/LineageOS/android_device_fairphone_FP6/commit/768592057b3c1a457f7a0134ef157336f01319ee

Today, a firmware update for the Fairphone 6 was released, which seems to solve the IPv6 issues on my device.

Now, I am not saying that all mentioned IPv6 issues in a OPNsense managed IPv6 network stem from faulty Android drivers, but I wanted to point out that this is at least a possibility to consider.

I hope this helps.

Best regards,

Astronaut

P.S. OPNsense rocks!