I will mark it as the solution, though I suspect it will crop up more as this latest update to windows 10 is rolled out, but more importantly each time a "new" or "upgraded" app is rolled out. Windows seem to reset the network each time.
The first line in the IP
is actually the DNS address reported by Pi-hole at the conclusion of its re configure.
Since I do have root access on my router (yes Technicolor good guess by the way) I will investigate what I can do about disabling the IPv6 setup on it. Suspect it will be a bit tricky though, it is needed when pi-hole is not running.
Perhaps do some fancy sort of routing on the router for IPv6 only from the Raspberrypi.
Need to think on it a bit.I now know a little more on how IPv6 works, and on a bigger picture the implications of Apple developed their zero information setup protocol. I bet it was in part to make sure the user can't intervene so you can't put things like pi-hole in the mix and block their adds.
I will update the topic if i work out some solution to the router.
On my network I also have Tizen running (TV) and not sure if that does IPv6.
Again thanks for your help.
EDIT: On further thought, perhaps the router does not need to do any IPv6 at all. The internal network will not have IPv6 without the pi-hole (unless Tizen provides it) but that's OK.
No, bonjour / avahi / zeroconf do not contribute to your problem.
Your issue is this:
Your clients will correctly receive DNS servers via IPv6 as advertised on your network by both your router and Pi-hole, but your router doesn't allow you to configure to advertise Pi-hole's IPv6 address instead of its own.
IPv6 is working as intended, it's your router that's not playing along well.
Note that the DNS protocol doesn't care whether it's transported over IPv4 or IPv6.
DNS will flawlessly resolve hostnames to IPv4 as well as IPv6 addresses as requested, regardless whether that request was received via IPv4 or IPv6.
Provided your router supports it, disabling IPv6 completely is a good choice if you aren't sufficiently familiar with IPv6 yet.
I didn't articulate that very well. I didn't mean my problem, I meant the general case where there are multiple possibilities of DHCPIPv6 and that a client could have preferences hard coded into the client software by for instance, Microsoft or Apple.
One question though is what happens at startup of the raspberry pi if there is no DHCPIPv6 on the network, will it set itself up, then provide the service?
(i am thinking of power outages and uncontrolled restarts)
Well it turns out I can disable DHCPIPv6 on the router. (well sort of I can't actually tell whether it has stopped or reduced function).
But if I do, I get no DHCPIPv6. Raspberry Pi does not appear to implement DHCPIPv6 even though the packages seem to be there. Normally it probably doesn't need to but I would think that may be enabled in the future, particularly if it is sold as a desktop.
Pi-hole doesn't seem to either as a standalone, but it does propagate its addresses to the DHCPIPv6 on other devices (modem).
Guess I am going to delve a little deeper than I intended.