SOA Record Lookup
Read a domain's Start of Authority record — its primary name server, serial number and zone-refresh timers.
The SOA (Start of Authority) record sits at the top of every DNS zone. It names the primary authoritative name server, the zone administrator's contact, a serial number that increments on each change, and the refresh/retry/expire/minimum timers secondary servers follow.
Checking the serial number is the quickest way to confirm a zone change has been published. Enter a domain above.
Frequently asked questions
What does the SOA serial number tell me?
It increments every time the zone is edited. If your secondary servers show an older serial than the primary, they haven't picked up your latest changes yet.
What are the refresh and retry timers?
They tell secondary name servers how often to check the primary for updates (refresh) and how soon to retry after a failure (retry).
What is the minimum/TTL value?
Historically the default record TTL; today it primarily sets the negative-cache TTL — how long "no such record" answers are cached.