DNS TTL and Propagation: Why Changes Take Time

Quick answer: DNS TTL controls how long a resolver may cache a record before asking for fresh data. That is why a DNS change can appear at different times in different places.

TTL is a cache instruction

A low TTL generally allows changes to be picked up sooner, while a higher TTL can reduce repeated DNS queries. Resolvers can also have operational behavior that affects exactly when a cached response expires.

How to troubleshoot a change

Check the authoritative answer and compare results from multiple resolvers. Do not assume that one local cached answer represents the entire internet.

Use DNS Lookup to inspect current public DNS results.