[help] systemd-resolved how to keep DNS server order?
I have a pi hole in my network and I set it as my primary DNS server, and my router (a Mikrotik) as secondary. DHCP sets the DNS servers as pihole, mikrotik in this exact order and I want to keep it that way. I know systemd-resolved uses some algorithm to set the fastest dns as current server, but I don't want/need that. Is there some way to do configure it to just let it be?
You can't. Well, you shouldn't rely on queries going out in any particular order. All of your DNS servers should behave the same way as clients may fail from the first one to a secondary.
Why do you care which one is being used? What are you trying to do?
I want to have ads blocked with pihole and at the same time to have local DNS served by the router. I know pihole does local DNS, but RouterOS (mikrotik) is much better suited for that.
Yes, you can configure systemd-resolved to use the DNS servers in the order provided without dynamically switching based on speed. Here’s how you can do it:
Replace IP_of_pihole and IP_of_mikrotik with your actual DNS IP addresses. This tells systemd-resolved to only use the DNS servers in the order you've specified.
Prevent automatic DNS changes by network manager:
If you're using NetworkManager, create a drop-in configuration to prevent it from overriding DNS settings: