Which engineer invented the Domain Name System in 1983?

Paul Mockapetris invented the Domain Name System in 1983.

Before DNS, the growing ARPANET relied on a centrally maintained HOSTS.TXT file that mapped computer names to numerical addresses. As more networks and machines joined, maintaining one master file became impractical. Paul Mockapetris designed DNS as a distributed and hierarchical alternative.

DNS divides names into levels, such as host, domain, and top-level domain. Specialized name servers can answer queries for their own portions of the namespace, while resolvers obtain and cache results for users and applications.

The system is commonly described as an Internet phone book, but that analogy is incomplete. DNS can provide several kinds of records, including mail-routing MX records and text TXT records, not just address mappings. Mockapetris’s design also introduced delegation, allowing separate organizations to administer different parts of the global namespace.