This topic

IP6

CanardNoir — Mon, 24 Nov 2025 18:20:28 GMT

Does anyone here know who you contact at BT to get confirmation that their network can successfully route IP6?

Re: IP6

WSH — Mon, 24 Nov 2025 18:35:24 GMT

No but I can confirm that BT's IPv6 implementation works absolutely fine.

My own Windows 11 kit doesn't usually use IPv4 these days. Everything external seems to be routed as IPv6 and has been for a long time now.

Re: IP6

CanardNoir — Mon, 24 Nov 2025 18:42:35 GMT

Despite WSH’s experience. BT seem not to have fully addressed the IPv6 routing issue. Their consumer broadband rollout is still dependent on IPv4, and IPv6 support seems inconsistent across their infrastructure. My BT Smart Hub setups advertise IPv6 locally, but the addresses are link-local or ULA (unique local), meaning they don’t route properly to the wider internet. This leaves us customers with the appearance of IPv6 capability but no functional end-to-end connectivity.

My BT’s Smart Hub 2 show IPv6 addresses in Windows and router status pages.

However, the addresses are non-global (e.g., starting with fe80::, fc, or fd ), which cannot be used for public internet routing.

As a result, some Microsoft applications, like GetHelp.exe, fail when trying to connect over IPv6, even though the system reports IPv6 is “enabled.”

At the moment the tech folk at BT tell customers who call for help that the problem is with their device and to re-boot it, use a different browser and clear their browser cache. It has nothing to do with the customer’s device, It is entirely a BT network issue. They should be honest and explain that BT hasn’t fully implemented IP6 yet (in spite of what they would like us to believe) and tell their customers to disable IP6 on their devices (there is no way for the customer to disable it on the Smart Hub). Once the devices use IP4 everything works again.

Better yet they could configure the Smart Hub to disable IP6 until they’ve got it sorted.

@whs Have you tried using gethelp.exe on your IP6 routed network?

Re: IP6

WSH — Mon, 24 Nov 2025 19:02:52 GMT

Doesn't seem to be a problem.

IPv6 does use a link local for local traffic but you should also get a public IP if the IPv6 on the SH2 is configured correctly.

Re: IP6

CanardNoir — Mon, 24 Nov 2025 19:05:48 GMT

There are no user configurable items related to IP6 addresses on my Smart Hub. They are all set by BT.

Re: IP6

WSH — Mon, 24 Nov 2025 19:15:26 GMT

Is that a Smart Hub or a Smart Hub 2? It is certainly user configurable on the SH2, at least as to whether it is Stateless, Stateful or off

Re: IP6

CanardNoir — Mon, 24 Nov 2025 19:19:24 GMT

It's a SH2.

Allocation mode it set to "Both."

What should it be?

Re: IP6

licquorice — Mon, 24 Nov 2025 19:25:14 GMT

Doesn't really matter, but with Stateless IPv6 fine here

Re: IP6

licquorice — Mon, 24 Nov 2025 19:27:43 GMT

A quick test for IPv6 connectivity is https://loopsofzen.uk which is an IPv6 only site.

Re: IP6

WSH — Mon, 24 Nov 2025 19:31:41 GMT

It’s difficult to gauge your level of experience, so forgive me if I’m stating the obvious here, but unlike IPv4 only the public prefix is supplied by the ISP. I take it you appreciate that you’ll need to pass that to your devices by router advertisement and SLAAC if they are to get a functioning global address?

Re: IP6

CanardNoir — Mon, 24 Nov 2025 19:32:08 GMT

Re: IP6

licquorice — Mon, 24 Nov 2025 19:38:01 GMT

So can you reach https://loopsofzen.uk

Probably wise to mung your addresses

Re: IP6

CanardNoir — Mon, 24 Nov 2025 19:41:51 GMT

Using DHCP this is how my Win11 device network is configured (with IP6 enabled). This config does not allow gethelp.exe to connect to MS. Disabling IP6 (on the PC) does.

Re: IP6

licquorice — Mon, 24 Nov 2025 19:54:52 GMT

IPv6 doesn't use DHCP, its a whole different mechanism.

Re: IP6

CanardNoir — Mon, 24 Nov 2025 19:58:29 GMT

The addresses on the Win11 PC match the addresses in the router and I didn't put them there so it got them automatically from the router using whatever it uses.

Re: IP6

licquorice — Mon, 24 Nov 2025 20:05:47 GMT

You haven't answered if you can access loops of zen

Re: IP6

CanardNoir — Mon, 24 Nov 2025 20:07:14 GMT

I can 🙂

But still can't access MS Gethelp.exe using IP6.

Re: IP6

Crimliar — Mon, 24 Nov 2025 22:19:34 GMT

Gethelp.exe is a local executable file and doesn't depend on IPv4 or IPv6.

I've been using native IPv6 without issue since joining BT and have had no issues using the stateless mode on my third party router. Through DynV6 DDNS I even have a couple of device that I can make directly routable - when I choose to do so! That third party router is lacking a bit when it comes to stateful mode though.

Re: IP6

CanardNoir — Tue, 25 Nov 2025 08:38:01 GMT

Thank you, Crimliar but oh dear! Opinion is divided then!

MS think that gethelp.exe (whilst it executes locally on one's machine) needs to communicate with their servers to do its work. Without IP4 or IP6 connectivity further down the network stack (at the transport layer perhaps) enabling communication back and forth to the application layer, gethelp.exe returns the error page I'm experiencing saying it "can't access the app".

I thought it must be a bit like MSEdge or Outlook which, undeniably, execute locally but are not fully functional without the underlying network stack routing IP packets correctly and complain when they don't get the expected response to their comms attempts.

Certainly, MS's explanation seems to me to make sense and accounts for the behaviour I see on my Win11 device but they could be wrong and, as Crimliar implies, gethelp.exe doesn't actually need real-time access to their servers to do its work. My disabling IP6 causing it to work is just a co-incidence (or the influence of a evil spirit possessing my machine 😀).

Trying to resolve this dichotomy drove me, reluctantly, to various AI apps. They all seem to agree (or are subject to the same hallucination). The gist of their opinions is that gethelp.exe needs to communicate with MS servers or it returns an error (the same one I get) and BT have not finished rolling out IP6 across their infrastructure. There are, according to the AIs, various UK geographic areas currently unable to fully route IP6. It turns out I live in one of them. Who knew! AI's universal recommendation is to disable IP6 and use IP4. Which is exactly what seems to work for me.