DNS propagation
The lag between changing a DNS record and everyone seeing it, caused by cached answers expiring rather than by any distribution.
Updated August 14, 2026
DNS propagation is the delay between saving a record and every visitor seeing the new value. The name is misleading, because nothing is being propagated. Your authoritative nameservers carry the new value the instant you save it; the delay lives entirely in the caches between them and your visitor. Every resolver that asked earlier holds its answer until that answer's lifetime runs out, and only then asks again.
The consequence is worth internalising: the wait is governed by the record's previous lifetime, not the new one. Lowering a record's time to live and changing it in the same sitting does nothing for the caches already holding the old copy — they keep it for the old duration. Plan a move in two steps: lower the value, wait out the old lifetime, then make the change.
This also explains the strangest symptom of connecting a short domain — it works for a colleague and not for you. Your resolver or browser is still holding the previous answer. Query the authoritative servers directly, or test in a fresh private window, before deciding the setup failed.