What is a DNS SOA Record? | Definition, Function & Example
A DNS SOA Record (Start of Authority Record) is a critical DNS record that defines the primary source of information for a domain's DNS zone. It contains administrative details such as the primary name server, the email of the domain administrator, and timers for DNS synchronization between servers.
Key Functions of a DNS SOA Record:
- Designates zone authority: Identifies the master DNS server for a domain.
- Controls zone transfers: Provides refresh and retry intervals for secondary DNS servers.
- Stores administrative contact info: Includes the responsible party's email address.
- Tracks record changes: The serial number is incremented with each DNS update.
Example of a DNS SOA Record:
example.com. IN SOA ns1.exampledns.com. admin.example.com. (
2025052301 ; Serial
7200 ; Refresh (2 hours)
3600 ; Retry (1 hour)
1209600 ; Expire (2 weeks)
86400 ; Minimum TTL (1 day)
)
Note: The email is written as admin.example.com. instead of admin@example.com.
Best Practices for DNS SOA Records:
- Always increment the serial number after DNS updates.
- Use realistic timing values for refresh and retry intervals.
- Ensure the admin email and primary name server are correct and reachable.