SOA Records

Name of primary DNS server
The domain name of the primary DNS server for the zone.
The zone should contain a matching NS-record.

Mailbox of responsible person
The email address (replace @ with a dot) of the person responsible for maintenance of the zone.
The standard for this is the "hostmaster" username - such as "" (=

Serial number (see Zone Transfers)
Used by secondary DNS servers to check if the zone has changed.
If the serial number is higher than what the secondary server has, a zone transfer will be initiated.
This number is automatically increased when changes to the zone or its records are made.
Unless you have a specific reason for changing this numbers, it is best to let us manage it.
You should never decrease (lower) a serial number.

Refresh Interval (see Zone Transfers)
How often secondary DNS servers should check if changes are made to the zone.

Retry Interval (see Zone Transfers)
How often secondary DNS server should retry checking if changes are made - if the first refresh fails.

Expire Interval (see Zone Transfers)
How long the zone will be valid after a refresh.
Secondary servers will discard the zone if no refresh could be made within this interval.

Minimum (default) TTL
Used as the default TTL for new records created within the zone.
Also used by other DNS server to cache negative responses (such as record does not exist etc.).