The domain registry in turn configures the authoritative name servers for that top-level domain with delegations for each server for the zone. The registrar provides the names of these servers to the domain registry for the top-level domain containing the zone. When a domain is registered with a domain name registrar, the zone administrator provides the list of name servers (typically at least two, for redundancy ) that are authoritative for the zone that contains the domain. If the server for a zone is not also authoritative for its parent zone, the server for the parent zone must be configured with a delegation for the zone. The fully qualified domain names of the authoritative name servers of a zone are listed in the NS records of that zone. Įvery domain name appears in a zone served by one or more authoritative name servers. The contents of a zone are either manually configured by an administrator, or managed using Dynamic DNS. DNS provides a mechanism whereby the primary for a zone can notify all the known secondaries for that zone when the contents of the zone have changed. Examples of such mechanisms include DNS zone transfers and file transfer protocols. A secondary server for a zone uses an automatic updating mechanism to maintain an identical copy of the primary server's database for a zone. It is identified in the start-of-authority (SOA) resource record. A primary server for a zone is the server that stores the definitive versions of all records in that zone. Īn authoritative name server can either be a primary server or a secondary server. Name servers can also be configured to give authoritative answers to queries in some zones, while acting as a caching name server for all other zones. An authoritative-only name server returns answers only to queries about domain names that have been specifically configured by the administrator. A DNS name server is a server that stores the DNS records, such as address (A, AAAA) records, name server (NS) records, and mail exchanger (MX) records for a domain name (see also List of DNS record types) and responds with answers to queries against its database.Īn authoritative name server is a name server that gives answers in response to questions asked about names in a zone. Below the root, Internet resources are organized into a hierarchy of domains, administered by the respective registrars and domain name holders. DNS servers, which are located all over the world, translate domain names into IP addresses, giving them control over which server (a user), may access via a given domain. The top hierarchy of the Domain Name System is served by the root name servers maintained by delegation by the Internet Corporation for Assigned Names and Numbers (ICANN). Internet name servers implement the Domain Name System. The Domain Name System maintains the domain namespace and provides translation services between these two namespaces. The Internet maintains two principal namespaces: the domain name hierarchy and the IP address system.
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