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SOA Record Lookup

Enter a domain to view its SOA record, including primary nameserver and zone serial number.

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How to use SOA Record Lookup

The SOA Lookup retrieves the Start of Authority record for a domain — the master record at the top of every DNS zone that holds its administrative settings: the primary name server, the responsible contact, the serial number, and the timers that govern how secondary servers refresh and how long failures are cached. The SOA record is foundational to how a zone is maintained and propagated, so reading it is essential when diagnosing replication problems between name servers or confirming that a zone update has actually been published.

  1. Enter the domain whose SOA record you want to read.
  2. Click Lookup to fetch the Start of Authority record.
  3. Note the primary name server and admin contact.
  4. Check the serial number to confirm the zone version.
  5. Review the refresh, retry, expire and TTL timers.

Inside the SOA record

The SOA record names the primary (master) name server for the zone and the email address of the administrator, with the @ written as a dot by convention. Its most operationally important field is the serial number, which the zone owner increments on every change; secondary servers compare serials to decide whether they need to pull a fresh copy. The remaining timers — refresh, retry, expire and minimum TTL — control how often secondaries check for updates, how soon they retry after a failure, when they stop serving stale data, and how long negative answers are cached.

SOA fields
FieldPurpose
MNAMEPrimary name server
RNAMEAdministrator email (dot for @)
SerialZone version number
Refresh / Retry / ExpireSecondary update timers
Minimum TTLNegative-answer cache time

Why the serial number matters most

When you change a DNS record but secondary name servers still serve the old value, the serial number is the first thing to check. Secondaries only fetch a new zone copy when the primary’s serial is higher than the one they hold, so an administrator who edits records but forgets to bump the serial leaves the secondaries unaware anything changed. Watching the serial increase confirms a change was published and gives the secondaries permission to update. This makes the SOA serial the single most useful field for diagnosing zone-propagation issues.

Glossary

SOA record
The Start of Authority record holding a zone’s administrative settings.
Serial number
A version number secondaries use to detect zone changes.
Primary name server
The master server holding the editable copy of a zone.
Refresh / retry / expire
Timers controlling how secondaries sync with the primary.
Minimum TTL
How long negative (not-found) answers are cached.

Related reading

Frequently Asked Questions

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Why use SOA Record Lookup?

  • Real-time DNS lookups using live resolver queries
  • Supports IPv4 and IPv6 addresses
  • No software to install — runs entirely in the browser
  • Results include TTL values and record priority

Common use cases

  • Verify DNS propagation after updating nameservers
  • Check MX records when troubleshooting email delivery
  • Look up SPF/DKIM/DMARC records for email security audits
  • Test whether a SSL certificate is valid and up to date
  • Find the IP address behind a domain name

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