At home I run a Raspberry Pi with PiHole. Every device obtain its IP via DHCP and some devices have a reserved address. The router is configured to offer my Raspberry Pi as primary DNS, for every device this works well, except for my laptop with Ubuntu.
Quite often (like every day) my DNS is changed to my second DNS option. I can revert this change with resolvectl dns <interface> <ip>, but IMHO this should not happen. If I assign a primary DNS, it should be the one used, not matter what, unless it cannot be reached.
What could be the reason for having Ubuntu changing my primary DNS?
Update:
This is what the logs says about the automatic change. Aparently, there is no reason to pickup the second DNS over the first.
