One unit of data in the domain name system. A resource record defines some attribute for a domain name such as an IP address, a string of text, or a mail route.

A resource record consists of five components:

A Resource record starts with a domain name , usually a fully qualified domain name. If anything other then a fully qualified domain name is used, the name of the zone the record is in will automaticly be appended to the end of the name.

Second is the TTL, in seconds, defaults to the minimum value determined in the SOA record.

Third is the Record class: Internet, Hesiod, or Chaos

Fourth is the record type: CNAME, PTR, A, etc.

Fifth is the record data: (depends on record type) If the record data includes a domain name that is not a Fully Qualified Domain Name it goes through the same appending process as the domain name at the start of the record.

Many servers will permit comments as a sixth component.