Expected Behaviour:
VoIP phone DNS should be found after router's reboot
Actual Behaviour:
Router can't find VoIP DNS. Phone connects after manual setup only
I switched to a new router recently. I set everything up as before, except that the Pi Hole now also handles DHCP since the (newer!) router won't let me define specific IPs for my devices.
The internet works fine. But the router "loses" connection to the VoIP phone and I then cannot make or receive calls. When I go back into the router's menu and manually set up the phone again and save, everything works fine again. Until the router reboots. (And sometimes, it seems, the router loses the phone connection during normal operation without a reboot.)
This is the failure message:
"Registering with VoIP number XYZ failed: Reason: DNS error. (V001)"
When I disconnect the Pi and let the router choose the DNS, this does not happen and it finds the phone provider's DNS on startup just fine.
I tried to configure a secondary DNS aside from the Pi Hole, but that didn't change anything during boot-up. Also, the Pi of course doesn't filter properly anymore.
It seems to me that the new router can't find the VoIP provider's DNS because I set up the Pi as DNS provider. Again, when I manually connect the phone in the menu after reboot, everything is fine and dandy. But I surely cannot do that every time the router reboots or gets a new IP from the ISP.
So I was wondering if I can write something in some file on the Pi so that the router will find the phone's DNS on reboot. (This was not necessary with the older router.)
Is this possible? Has anyone else had a similar problem?
Opening ports 5060 and 5064 for VoIP also didn't help (and was not necessary for the old router anyway and is not recommended).
IPv6 is switched off in the router, like on the old one.
The Pi Hole, by the way, is always on during the router's reboot, so the router should find the DNS since the Pi is primary DNS provider.
Otherwise I will have to switch back to the older (and slower) router.
Thanks.