{name} {ttl} addr-class NS Name server's_name
IN NS ucbarpa.Berkeley.EDU.
The Name Server record, NS, lists the name of a machine that provides domain service for a particular domain. The name associated with the RR is the domain name, and the data portion is the name of a host that provides the service. Workstations providing name service need not be located in the named domain. There should be one NS record for each master server (primary or secondary) for the domain. If you use more than approximately 10 to 15 NS records for a zone, you may exceed DNS datagram size limits.NS records for a domain must exist in both the zone that delegates the domain and in the domain itself. If the name server host for a particular domain is itself inside the domain, then a glue record is needed. A glue record is an Address (A) record that specifies the address of the server. Glue records are needed only in the server delegating the domain, not in the domain itself. For example, if the name server for domain SRI.COM is KL.SRI.COM, then the NS and glue A records on the delegating server look like this:
SRI.COM. IN NS KL.SRI.COM. KL.SRI.COM. IN A 10.1.0.2The administrators of the delegating and delegated domains should ensure that the NS and glue A records are consistent and remain so.