Each Zone contains one SOA Record, which holds the following parameters for the Zone:
- 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 the Responsible Person: The email address of the person responsible for maintenance of the Zone.
- Serial Number: 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 by our Servers when changes to the Zone or its Records are made.
- Refresh Interval: How often Secondary DNS Servers should check if changes are made to the zone.
- Retry Interval: How often Secondary DNS Server should retry checking, if changes are made - if the first refresh fails.
- Expire Interval: 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.).
There you would find 5 editable fields:
- Responsible Person: The email address of the person responsible for maintenance of the Zone.
- Refresh: The Refresh Interval indicates how often Secondary Name Servers should check if changes are made to the Zone. You can decide your own value for this Interval.
- Retry: The Retry Interval indicates how often the Secondary Name Servers should retry checking, if changes are made - if the first refresh fails.
- Expire: The Retry Interval indicates 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.
- TTL: This is the Time To Live for this Record. Any Server which once queries this Record will query it again after this time interval. The ideal TTL is 86400, which is 1 day. It can not be set to less than 14400, i.e. 4 hours.
Apart from these, the SOA Record also includes a parameter Serial. This is a number that is automatically generated by our Servers. All Secondary Name Servers cache the Serial Number in the SOA Record, such that when a Serial Number change is detected by Secondary DNS Servers, it updates its Records with the changes. This number is automatically increased by our Servers when changes to the Zone or its Records are made.