SOA record lookup: check zone authority records
TL;DR. The SOA record sits at the apex of every zone and declares the primary name server, hostmaster email, serial number and refresh/retry/expire/minimum-TTL values.
How the SOA record works
Bumping the SOA serial is what tells secondary name servers to re-sync. Old-school operators bump it in YYYYMMDDnn format; most cloud DNS providers do this automatically on every change. Checking the SOA serial across global resolvers shows whether every authoritative server has picked up your latest zone edit.
Example SOA record
example.com. 3600 IN SOA ns.icann.org. noc.dns.icann.org. 2024010101 7200 3600 1209600 3600Check a SOA record live
Run the multi-resolver probe → and confirm propagation of your SOA record across 12 global resolvers in real time.
Reference
Spec: RFC 1035, RFC 1982.
SOA record FAQ
How do I check an SOA record? →
Enter a domain into dnsprobe and we read the SOA record from 12 global resolvers, letting you compare the serial number across servers to confirm a zone change has fully synced.
What does the SOA serial number do? →
The serial is a version number for the zone. When you raise it, secondary nameservers see a newer serial and pull a fresh copy of the zone, propagating your changes.
What are refresh, retry and expire in an SOA? →
They are timers for zone transfers: refresh is how often secondaries check for a new serial, retry is the wait after a failed check, and expire is how long stale data is served before the secondary stops answering.