IPV6 not working for windows.

[garry-w-x]

So I am new to Virgin. It was installed in July. Let me first say I know networking, it was my job for 30+ years. It is as far as I know a Sagecom modem. It introduces itself as Vincent. I was recently checking things out network wise and discovered that IPV6 is only providing local connectivity. This is a brand new window 11 lenovo. It says that from the network status for IPV6. The modem gives me 3 Internet routeable addresses. I have tried a second windows machine. I also have another residence and the provider is Rogers, running on an XB7 modem. IPV6 works fine from the same windows machine. Using https://test-ipv6.com/ gives 10/10 for the test on the XB7 and 0/10 on the Virgin Modem. This result is wired or wireless for two windows laptops. Strangely I have a Samsung S21-FE and the test works perfectly. I made sure that the cellular was turned off so that it would rule out using cell for a non-working local network.  So what is going on between windows 11 or 8.1 and the Virgin Modem? I am not currently at the Virgin location but will be there in a couple of days. From a technical perspective, the only thing I can think of is the Samsung is using a randomized MAC Address. When I get back there again I will change the windows mac to a locally administered one to see if anything changes. Looking for feedback from anyone. Wireshark indicates packets being sent to the modem default gateway mac with no response from any site set as the destination. 

[Toll Booth Willie · Accepted solution]

Be aware that there is an issue with the Vincent modem not assigning IPv6 addresses correctly. I started a thread a while back regarding apps not working correctly and later identified that it was related to IPv6. The last thing I heard, a couple of weeks ago, was that the tech team was working on a fix with the modem vendor.

[garry-w-x]

It's a weird one. It gives me 3 networks in the router advertisement. The one the phone picks must work and the one windows picks does not. Very strange. Is it possible to put the thing in bridge mode and get a decent router that can run ipv6. I went back to the cottage and ipv6 worked at first and then stopped working. My Rogers works like it should. 1 prefix not 3. Perhaps I should figure out the working prefix and static address my devices, at least for windows anyway. 

[garry-w-x]

It appears to have been fixed. I now get only one network from the modem and ipv6 works. 

Now the modem does not work as an ipv4 domain name server.  Manually configuring 8.8.8.8 and 8.8.4.4 in the interface works. Fortunately the ipv6 dns server ip works. Bad news is that Android prefers to use ipv4 dns and reports that the network is not connected to the internet unless I manually configure the dns as above. 

[Toll Booth Willie]

That's strange. Has your modem firmware version been updated recently? Mine has not, it's still sitting at 2.13 and I haven't seen a fix yet.