DNS Propagation Checker
Just changed a DNS record or moved hosting? See whether public resolvers in several countries already use the new value, compared directly with what your domain's nameserver answers.
DNS propagation, briefly.
What is DNS propagation?
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After a DNS record changes, resolvers around the world keep the old answer cached until its TTL runs out. Propagation is the time until every resolver uses the new value. The change itself is live on your nameserver right away; what you wait for is caches expiring.
How long does DNS propagation take?
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At most the TTL of the old record, usually 5 minutes to a day. A nameserver change at the registrar can take up to 48 hours, since NS records at TLD servers like .com usually have a TTL of 1 to 2 days. Lower the TTL a few hours before a move to make the switch faster.
Why do some resolvers give a different answer?
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Most often an old cached answer that has not expired yet. It can also be GeoDNS or load balancing (a CDN, say), which hands out different IPs per location on purpose, or a resolver that filters certain domains.
Can I use it from a terminal?
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Yes. curl 'ipku.in/en/tools/dns-propagation?q=example.com&type=MX' returns every resolver's answer as plain text, and /api/propagation/example.com?type=MX returns JSON.