alt Hacker NewsIn 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.
Replies
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.
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.
DNS servers do in fact do that but it would not be a good look for the world's largest DNS provider.