IPv6 works on mobile but not on laptop

I am using a Netgear D7000 to connect and I am having a few gremlins when I try to enable IPv6

I have set the IPV6 setting to "Auto detect" then applied the settings.
When I look at the page again I can see that it has auto chosen "6to4 Tunnel" as it's operating mode.

So far so good.

If I open the test site https://ipv6-test.com/ on my Android phone it detects that I have an external IPv6 address.
However when I open the same site on my laptop it says IPv6 not supprted.

My DNS server settings are OpenDNS servers [208.67.222.222 · 208.67.220.220]

I have used my laptop at my daughter's house via BT Internet and I get IPv6.

Has anyone got any idea what I need to tweak to get IPv6 on my laptop with a D7000?

It will work at your daughter's because BT actually support IPV6.
Your daughter's BT Hub will provide the laptop an IPV6 address.

Plusnet do not support IPV6/provide an IPV6 address.

Why the tunnel works on Android and not your laptop I have no idea.

Does the ipv6-test site tell you who the ipv6 address ISP is when using the Android phone?

Edited by j0hn83 (Mon 07-Jun-21 22:20:35)

In reply to a post by j0hn83:

It will work at your daughter's because BT actually support IPV6.
Your daughter's BT Hub will provide the laptop an IPV6 address.

Plusnet do not support IPV6/provide an IPV6 address.

Why the tunnel works on Android and not your laptop I have no idea.

A feature on the newer iOS and Android phones uses Mobile data if the Wi-Fi can't connect.
So it's most likely using mobile data to connect to the IPV6 site.

Thanks
Dan

I would expect it to use IPV4 rather than switching to mobile data.

I think it's the only logical explanation as PlusNet does not support IPV6.
The phone could be doing that as it can see the Mobile Data has an IPV6 address.

Thanks
Dan

In reply to a post by j0hn83:

I would expect it to use IPV4 rather than switching to mobile data.

You are assuming the website has an IPv4 address. For most websites they probably do have an IPv4 address but this assumption might not always be true (since the ipv6-test website is designed to test IPv6 it is probably trying to access an IPv6 address). If the website doesn't have IPv4 then there is no other way to connect to it other than using your mobile data.

In reply to a post by aidanh:

In reply to a post by j0hn83:

I would expect it to use IPV4 rather than switching to mobile data.

You are assuming the website has an IPv4 address. For most websites they probably do have an IPv4 address but this assumption might not always be true (since the ipv6-test website is designed to test IPv6 it is probably trying to access an IPv6 address). If the website doesn't have IPv4 then there is no other way to connect to it other than using your mobile data.

I'm not assuming anything. It does have an IPV4 address.

The OP even says so..

However when I open the same site on my laptop it says IPv6 not supprted.

An IPV6 test site that can't display results to an IPV4 connection would be pretty useless.

Windows doesn't fall back to mobile data because a single website is IPV6 only anyway.
It simply wouldn't load.

It can display results over IPv4 but in order to test IPv6 it has to query an IPv6 address. It does this by querying v6.ipv6-test.com which doesn't have IPv4. The Android phone goes "I need to connect to this IPv6-only site that doesn't have IPv4 and I can't do this via WiFi because the Internet service provider doesn't provide Internet but I can do it using mobile data".

Edited by aidanh (Mon 07-Jun-21 21:26:02)

Android phones don't work that way either.

See daniel's post here: https://forums.thinkbroadband.com/plusnet/t/4685707-...

Your phone is multihomed when connected to Wifi and mobile data at the same time, if it can't get a route over one connection it will try the other. It may even try both at the same time and use which is fastest (reference for iOS: https://developer.apple.com/videos/play/wwdc2015/719/ but I imagine Android does something similar).

I just tested this on 2 Android devices, both running Android 11.
A Google Pixel and a Samsung.

If I disable IPV6 on my home connection and visit https://ipv6-test.com/
neither phone falls back to mobile data (which supports IPV6).
Both return an IPV6 unsupported result.

That's the behaviour I expected to see.

I don't have 1 to test but I think an iPhone would also show the home connection doesn't support IPV6 rather than returning the MNO's IPV6 address.

The IPV6-test site tells the OP what ISP the IPV6 address belongs to so it's easy to check either way.

My Nokia 8 is sadly stuck on Anroid 9, so not sure if that has any bearing on this.

Anyhow conducted another set of tests this morning

D7000 IPv6 mode = "6to4 Tunnel" (Auto detected)

Switched on Airplane mode (to stop mobile data) then turned on WiFi again so I should be connected via WiFi only.

When I opened Chrome (www.google.co.uk) I got a warning that 6to4 is being deprecated shortly.
My phone still finds an IPv6 address, according to the ipv6 test site of type 6to4.

Both the IPv4 and IPv6 addresses are listed as "British telcominications PLC"

If I solely go mobile with no WiFi the ISP is listed as "EE Limited" for both.

If I turn off IPv6 I get back to only IPv4 supported.

One thing I note throughout this is that my external IPv4 Address does not change when I eneble of disable IPv6. (Expected as I do not have the static IP option enabled)

Should I reboot the router between changes of IPv6 settings?