DNS propagation checker

After you change a DNS record, resolvers around the world keep serving the old answer until their cached copy expires. Propagation is the time it takes for all of them to fetch the new one. Nothing is pushed out: each resolver updates when its TTL runs out.

Up to the TTL of the old record, which is often 5 minutes to 1 day. A change of nameservers at the registrar can take up to 48 hours, because the top-level domain servers cache the delegation too.

Enter the domain, choose the record type you changed, and press Check. The tool asks four public resolvers at once and shows whether they agree, with the TTL left on each cached answer.

Large sites and CDNs answer with a different address in each region on purpose, to send visitors to a nearby server. For those, a difference in A or AAAA records is normal and not a propagation problem.

Plan ahead. A day before the change, lower the TTL on the records you will change to 300 seconds. After the change, every resolver picks up the new value within 5 minutes. Raise the TTL again afterwards.