DNS, or the Domain Name System, is the system that translates human-readable domain names into IP addresses.
People can easily remember names such as example.com, but computers and network protocols use numerical IP addresses to locate services. When you visit a domain, a DNS resolver looks for the corresponding record, often using a cached answer or querying other DNS servers. The result tells the browser where to send its connection request.
DNS is hierarchical and distributed rather than being one giant central directory. Root name servers direct queries toward top-level domains such as .com or .org, and authoritative name servers provide the records for individual domains. This structure also lets organizations change server locations without forcing users to learn new names.
Paul Mockapetris developed DNS, and the system became essential to the Internet during the 1980s. DNS can provide both IPv4 and IPv6 addresses. It is sometimes called the Internet’s phone book, although it also supports mail routing and other records. DNS is not the same as DHCP: DHCP automatically configures network settings, while DNS resolves names.