Comment by otterley
11 hours ago
In DNS, the owner of each record has full control over its TTL. Intermediary DNS servers are required to honor them and are not permitted to replace TTLs with their own.
11 hours ago
In DNS, the owner of each record has full control over its TTL. Intermediary DNS servers are required to honor them and are not permitted to replace TTLs with their own.
DNS servers do in fact do that but it would not be a good look for the world's largest DNS provider.
I don't think cloudflare cares about how it looks, also I think Google is bigger.
Actually that is not true. The IETF has expanded the definition of “TTL” and explicitly permits resolvers to serve “stale” RRs beyond their expiration time.
https://www.rfc-editor.org/info/rfc8767/
As a corollary, there is obviously no floor on refetching unexpired RRs, of course, except for efficiency concerns.
That's only when the authoritative server cant be reached though
You are obliged to pass on the TTL, you're not obliged to cache according to it.
At least in my country (UK) I know of no law relating to DNS caching.
Why throwaway perfectly good data every few minutes that is only modified every couple of years, just so someone can move their domain quickly when they eventually wish to? It is my contention that a [caching] DNS service can do far better. Trusting user (domain owner) input blindly is not for me.
It's not some sort of public law with public enforcement, but it is in the RFCs that govern the protocol.
I should be a bit clearer here; the TTL is an upper bound on how long it can be cached. Caches are free to consult more frequently but not less frequently. That said, out of respect for upstream cache operators and authoritative servers, most DNS caches honor TTLs as best they can.
The IETF isn't the internet police. You don't have to follow its advice.
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