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?
It depends on what you can consider “the ability”. If by ability you mean have to deploy a team of engineers working for a week to make it happens, that’s okay, if they’ve their system built for it things are different.
I can do this in like 5 seconds with my PiHole and not only am I not a network engineer, I would encourage people to never employ me as such.
So for an actual business that has a bigger budget than me ($0) and more hours to devote to it than me (.02), shouldn’t it be less of a problem?
Exactly and consider Cloudflare for instance, adding an “if domain block” is easy but then once you’ve thousands of servers running the same piece of software across the globe deploying updates and features becomes way slower and way harder. You’ve to consider tests, regressions, a way to properly store and sincronize the blocklists across nodes etc…
I’m not saying it can be done, because it can. But it will take longer and it will be a problem for someone. Besides you only have that point and click interface in your PiHole that allows you to do it in .02 because someone spend a few hours developing the feature. :)
This is what we’re trying to explain to you, this is how DNS works. Those thousands of servers? Recusrive DNS resolvers, ran by Cloudflare. All watching and caching the records from Cloudflare’s authoritative nameservers in near real time, because that’s how it was designed. You don’t need to test for regressions, figure out how to properly store and synchronize the “blocklist” (it’s not a blocklist, it’s changing a domain record or simply using a CNAME to point to the registrar) or whatever else, because DNS is continuous, and it was designed to do what you’re describing, in the 90’s.
Yes, if you’re updating your infrastructure, you’d want to test. But this isn’t that.
Ever ran into an expired domain and thought about how the registrar can just park an expired domain and make it an ad for themselves? That’s just them adding a CNAME in their authoritative nameservers, which gets distributed globally. The prior delinquent owner can still be hosting, but because they don’t have the authoritative nameserver they can’t use the domain anymore.
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.