good evening,
I entered 2 DNS addresses in "Unbound DNS: DNS over TLS" and I need them to be processed with priority, so elect the primary and secondary.
If the first doesn't respond because it doesn't work, pass the execution to the second: can it be done?
When the first DoT server does not respond, Unbound treats it as unresponsive and applies a probing scheme with exponential backoff. Initially, failed queries receive a SERVFAIL response. Unbound then blocks the non-responsive server for a default period (typically 15 minutes, controlled by infra-ttl) and periodically sends a single probe query to test its availability.
During this time, Unbound automatically forwards new queries to the next available server in the configuration. Once the blocked server responds to a probe, it is reinstated into the pool for normal use