Domain Name System (DNS)

A distributed naming system that stores records for domains, including addresses, aliases, mail routing, verification, and delegated name servers.

A resolver follows DNS delegations and caches records for their time to live. A web lookup may return IPv4 or IPv6 addresses directly, follow an alias, or point toward a content-delivery platform. Authoritative name servers publish the records; registrars manage registration and delegation, though one company may provide both services.

Builder example

A wrong record, stale cache, missing certificate validation, or incorrect delegation can make a healthy deployment unreachable. Changes do not literally spread to every server at once; resolvers retain cached answers until their TTL and local policies allow refresh.

Common confusion: A domain name is the readable address you register, such as example.com. DNS is the lookup system that maps that name to the numeric address of a server. Buying a domain does not connect it to anything until you set DNS records that point it at your host.