Overview#DNS Resource Records are the basic information elements of the Domain Name System.
DNS Resource Records of the same type are described as a resource record set (RRset). The order of resource records in a set, which is returned by a DNS resolvers to an application, is undefined, but often servers implement round-robin ordering to achieve load balancing. The Domain Name System Security Extensions (DNSSEC), however, work on the complete set of resource record in canonical order.
Resource record (RR) fields
|NAME||Name of the node to which this record pertains||Variable|
|TYPE||Type of RR in numeric form (e.g., 15 for MX RRs)||2|
|TTL||Count of seconds that the RR stays valid (The maximum is 231−1, which is about 68 years)||4|
|RDLENGTH||Length of RDATA field||2|
|RDATA||Additional RR-specific data||Variable, as per RDLENGTH|