Networking Guide
Chapter 6, Configuring the Domain Name Service

DNS resource record syntax

DNS resource record syntax

Resource records use this general syntax:

   {name}    {ttl}    address class    record type    record specific data

``name''
This field is always the name of the domain record and it must always appear in the first column. For all resource records except the first in a file, the name can be left blank. In such cases, the name of the previous resource record is used.

``ttl''
This ``time-to-live'' field is optional. It specifies how long this data is stored in the database. If this field is left blank, the default time-to-live is specified in the Start of Authority resource record.

``address class''
This field lists one of three classes: IN for Internet addresses, HS for a limited subset of MIT/Athena ``Hesiod'' data, and ANY for all other address classes.

``record type''
This field shows the type of this record.

``record specific data''
Data in this field is dependent on the type of the resource record.

Case is preserved in name and data fields when loaded into the name server. All comparisons and lookups in the name server database are case-insensitive.