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Free SOA lookup

Look up the SOA record for any domain. Check the authoritative zone, the serial number, refresh timers and the minimum TTL.

Lookups use Cloudflare 1.1.1.1 from your browser.

Results appear here.

A stuck serial means the zone did not updateTenium’s DNS monitor notices when records change, which is the practical version of watching the SOA serial.

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What the SOA fields mean

The primary nameserver and the hostmaster mailbox come first. Then the serial (it should increase on every zone change), refresh (how often secondaries poll), retry (how soon to try again after a failure), expire (when secondaries stop serving a zone they cannot refresh) and the minimum TTL used as a negative-caching time.

Serial numbers

Many operators use YYYYMMDDnn. Two secondaries with different serials are serving different copies of the zone. That split is a common cause of “it works for some people”.

Related checks

NS lookup · DNS lookup · TXT lookup · DNS monitoring

Command-line equivalent

dig +multiline example.com SOA

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