DNS is the phonebook of the internet.
Nameserver records gives a hint where to find the nameserver for the subdomain. See https://serverfault.com/.
These records shows the fingerprint of your SSH server. Your DNS server needs to have DNSSEC enabled, otherwise this will not work.
https://unix.stackexchange.com/questions/121880/how-do-i-generate-sshfp-records
Sometime it's nessesary to flush the DNS servers of the big companies. These are the URL's to activate.
Normally Knot is not logging anything. If you really want this, take a look at https://jpmens.net/.