DNS, the Domain Name System, translates domain names such as wikipedia.org into IP addresses.
People use memorable names, while network software ultimately needs numerical Internet Protocol addresses to locate servers. DNS provides a distributed naming system that connects those human-readable names with records containing IPv4 or IPv6 addresses and other information.
A DNS lookup can involve a recursive resolver, root name servers, top-level-domain servers, and authoritative name servers. The result may be temporarily stored in a cache according to its time to live, or TTL. Caching reduces repeated queries and improves response speed.
DNS does more than find web servers. It also supports mail-exchange records, aliases, text records, and other services. DNS is separate from HTTP: DNS finds an address, while HTTP or HTTPS governs the transfer of web resources after a connection is made.