SOA Lookup
Inspect DNS zone metadata
Review Start of Authority (SOA) details for a domain.
Type a domain to check SOA records.
What is an SOA record?
SOA records describe the primary nameserver and timing settings for a DNS zone.
Key SOA fields
Serial tracks changes, refresh and retry control zone transfers, and expire defines cache limits.
Why SOA matters
SOA values affect propagation, zone transfers, and the stability of authoritative DNS.
SOA records explained
Every DNS zone has one SOA record that defines the primary nameserver, contact, and timing values.
Serial, refresh, retry, expire, and minimum TTL values control zone transfers and caching behavior.
Example SOA record
SOA values are returned as named fields for the zone.
| Field | Value |
|---|---|
| nsname | ns1.example.com |
| hostmaster | hostmaster.example.com |
| serial | 2024020101 |
| refresh | 3600 |
| retry | 600 |
| expire | 1209600 |
| minttl | 300 |
Serial should increase whenever the zone changes.
Refresh, retry, and expire values are expressed in seconds.
Error glossary
NXDOMAIN
The domain does not exist in DNS. Check the spelling or registration status.
SERVFAIL
The resolver failed to answer. This can be caused by DNSSEC issues or upstream outages.
Timeout
The DNS server did not respond in time. Try again or check connectivity.
Frequently Asked Questions
What is the SOA serial number?
It is a version number for the DNS zone. It should increase with each change.
Why do refresh and retry values matter?
They control how often secondary servers check for updates and retry failed transfers.
Is SOA required for every domain?
Yes. Every DNS zone must publish an SOA record.