NameServer

A name server, in the context of the Domain Name System (DNS), is a server that responds to queries about domain names. Name servers can act as recursive resolvers, which query other DNS servers on behalf of clients, or as authoritative servers, which hold DNS zone data and respond authoritatively for specific domains. In practice, many deployments combine roles: a recursive resolver may cache responses from authoritative servers to speed future queries.

When a client asks for the IP address of a domain, the query is typically handled by a recursive name server that begins at the DNS root zone, then follows the chain to top-level domain (TLD) servers, and finally to the authoritative name servers responsible for the domain. The authoritative servers provide definitive answers, which the recursive resolver caches for a period defined by DNS records' TTL.

DNS relies on various record types stored in zone files, including A (IPv4 address) and AAAA (IPv6 address) records, CNAME (canonical name), MX (mail exchanger), NS (nameserver delegation), and SOA (start of authority). An NS record delegates authority to other name servers, and an SOA record contains administrative information and cache timing.

Security and privacy considerations include DNSSEC, which signs DNS data to verify integrity, and transport-layer protections such as DNS over TLS (DoT) and DNS over HTTPS (DoH) to prevent eavesdropping and tampering. Network operators manage name servers with software such as BIND, Microsoft DNS, or PowerDNS, configuring zone files and service parameters.