I noticed that Quad 9 is not able to respond to the spy.pet
query:
$ dig spy.pet @9.9.9.9 +short
;; communications error to 9.9.9.9#53: timed out
But Cloudflare DNS is able to do it:
$ dig spy.pet @1.1.1.1 +short
104.26.0.165
104.26.1.165
172.67.74.73
And to be sure, I checked another domain with the same TLD to rule out the option that Quad9 is unable to handle the .pet
TLD, but I received a correct answer…
$ dig hello.pet @9.9.9.9 +short
3.64.163.50
Does Quad9 censor DNS queries?
The ability to selectively respond to DNS requests is integral to the function of DNS. The only real issue here is that there isn’t a standard response code indicating the reason for not returning the record like there is in http
The availability of such feature and how useful it might be to block something is dependent on the actual implementation (software) you’re using.