Fallback secondary upstream DNS

[borpin]

I want to specify a secondary upstream DNS server but I only want to use it if the primary actually fails. Currently it seems there is no priority so once it has started using the secondary, it keeps on using it.

Is that possible to specify with the current implementation (V5)?

[yubiuser]

It's not possible via web gui, but dnsmasq can do it.
Search for "strict-order" in the forum.

[borpin]

Great thanks.

As a note to anyone who finds this, add a file such as /etc/dnsmasq.d/02-strict.conf, with a single line of strict-order.

Note your preferred DNS should be listed as #2 in the Custom List (ref "strict-order" seems to be working in reverse - #4 by DL6ER)

@DL6ER, would be really great to have this as a check box so PiHole could simply add the directive and then add the servers into the conf file in the logical order.

[yubiuser]

GUI Supported strict-order

Assume a local business has a domain 'taco.rentals'. They setup a pi-hole with some upstream DNS servers. For this example, lets say the upstream point to their local DNS server and OpenDNS for additional filtering. Every so often when the business tries to resolve local services such as ad.taco.rentals or fileserver.taco.rentals. These local domain names resolve about 70% of the time because some of the queries to the local DNS sever while others go to the OpenDNS server. You can set up strict-…