Hi vcunat, thanks for your answer,
here are some followup questions:
Is there any way to set up knot-resolver via command line?
I could connect to turris with SSH.
But I need to know the sequence of commands to execute. So that I can add OpenNIC DNS servers to some list where knot-resolver is doing the domain lookups. If this is possible to be done (is it?), then I should be able to ping grep.geek (a domain on alternative DNS tree)
My other question is,
Could knot-resolver be configured in such a way, that I could use both - the default DNS and OpenNIC DNS and knot-resolver would be smart enough to validate DNSSEC based on the default DNS?
EDIT:
maybe what I am looking for is called DNS zone forwarding. Because I wanna use classical DNS, but for some specific domains like .coin or .geek I wanna use OpenNIC DNS server to resolve these.