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> When people say “we’re waiting for DNS to propagate”, what they actually mean is “we’re waiting for cached records to expire”. This shows a fundamental misun
by IncRnd 5y ago
> When people say “we’re waiting for DNS to propagate”, what they actually mean is “we’re waiting for cached records to expire”.
This shows a fundamental misunderstanding. It has nothing to do with push or pull. It also has nothing to do with when the information was propagated - before the request had been made or afterwards.
When you attempt to resolve a website's IP address from a URL, that is almost never done by sending a request to the authoritative server that owns that particular bit of information but to a caching resolver that requires the data gets propagated from the other server.
- Nevermark 5y agoCached records expiring doesn't "propagate" or "pull" or "push" anything. Cached records mean the next request will result in a cache miss, and so a higher level request up the chain. When that happens, a record is copied down the chain. Regardless of the mechanism, the data is now propagating.
- IncRnd 5y agoThat's mostly correct, but a new record isn't always propagated down the chain when there is a cache miss. Other resolvers may not yet have the updated record.