Every domain must have a Start of Authority record, it is a type of resource record containing information about the zone and especially zone transfers.
Serial number – Increments every time there is a change.
Primary Server – The FQDN of the primary or master name server for the zone file
Responsible person – mail address of the person responsible for the domain’s zone file
Refresh interval – The time that a secondary name server should wait between zone file update checks
Retry Interval – The time that a secondary name server should wait before trying to contact the primary name server after a failed attempt to check for a zone file update
Expires after – The time that the secondary name server will keep the zone file as valid.
Minimum TTL – Specifies the default Time To Live (TTL) for resource records
TTL for this record – the TTL of the SOA record
The SOA record can be modified in the GUI or by using dnscmd.exe
dnscmd /recordadd bigfirm.com @ SOA winserver.bigfirm.com mark.bigfirm.com 41 1800 60 2592000 7200