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My little LAN is connected to two ISPs and I internally run ULAs so I can make explicit client-to-ISP assignments by centrally NATing my clients onto the respective ISP prefix.
All Windows applications from ping to Edge can access the IPv6 internet without any issues. Nevertheless, probably thanks to the ULA, Windows 10 reports "no IPv6 internet access" upon checking the status of the LAN interface.
There must be some method that this part of the Windows OS uses to decide whether it has a routable IPv6 internet address or not. I already tried to play with the prefixpolicies table in netsh.exe, but to no avail, mainly because I'm having a hard time understanding the incredibly scarce documentation.
Is there some setting anywhere (netsh.exe, registry, where else?) where I can add an ULA range so all parts of Windows 10 recognize they do have working IPv6 internet access despite ULAs being in use?
unixtippse
Posted 2018-10-02T06:18:42.890
Reputation: 121
It's probably the ULA range. These are not expected to be globally routable, and prefix translation is generally considered doing it wrong. – Michael Hampton – 2018-10-02T12:53:22.673
IPv6 is designed to work without NAT, and ULA addresses are explicitly not globally routable. Windows is not wrong when it reports you have no internet connection, according to the IPv6 standaard – Sander Steffann – 2018-10-02T14:54:46.950
I have the he.net t-shirt and I've heard all the arguments for and against IPv6 NAT many many times. The PCs do have a perfectly working IPv6 internet connection, but it's being reported as faulty, although actually working, on Windows 10 only. Is that report based on anything configurable or not? This is much more of a Windows question rather than an IPv6 one. – unixtippse – 2018-10-02T17:42:23.887