nameservers

A nameserver is a server that participates in the Domain Name System (DNS) by storing and providing information about domain names and their associated IP addresses. Nameservers can be authoritative for specific zones or act as recursive resolvers that perform full lookups on behalf of clients.

In practice, a client query is sent to a recursive resolver, which queries root servers, then top-level domain (TLD) servers, and finally the authoritative nameservers for the requested domain to obtain the relevant resource records (such as A or AAAA records). The resolver caches responses to speed future inquiries and reduce load on authoritative servers.

Types and records: An authoritative nameserver holds a zone file containing resource records (RRs) for a domain, including NS records that delegate the zone and A/AAAA records that map names to IP addresses. Recursive resolvers may be provided by ISPs or operating systems. Glue records are A or AAAA records in parent zones that assist in delegating a zone when the name servers are within the domain itself.

Security and privacy: DNSSEC adds cryptographic signatures to DNS data to ensure data integrity and authenticity, though it does not encrypt queries. Privacy-conscious clients may use DNS over HTTPS or DNS over TLS to encrypt queries to resolvers.

Management and reliability: Domains point to their authoritative nameservers using NS records at the registrar. Good practice includes using multiple authoritative servers, load balancing, and anycast routing to improve availability.