Technical Library

Domain Name System

Introduction

History

Background

Pieces

Resource Records

Integration

Through the 1970s, the ARPANET, an experimental wide-area computer network across the United States, was populated by just a few hundred hosts. All the information that one needed to know about these hosts was stored in a single file, HOSTS.TXT. This file held a name-to-address mapping for every host connected to the ARPANET and was maintained by the Network Information Center ("the NIC") of Stanford Research Institute (SRI) in Menlo Park, California. Changes for the file were submitted to the NIC, and compiled into a new HOSTS.TXT once or twice a week.

As the number of hosts grew very large, problems arose with HOSTS.TXT. The network traffic and processor load on SRI-NIC was becoming uncontrollable. There was no authority over host names as well. There was nothing to prevent someone from adding a host with a conflicting name and breaking the entire system. Another problem was maintaining consistency of the file across the entire network. Changes to the hosts or additions were being made before a copy of the file could reach all of the ARPANET.

This system of a flat name space obviously did not scale well. A name space system needed to be created to ensure the uniqueness of names. The new system would allow local administration of data and be available to the rest of the Internet. Keeping data up-to-date would be much easier.

Paul Mockapetris, of USC's Information Science Institute, designed the architecture of the new system, the Domain Name System (DNS), to solve these problems.

This new architecture involves a hierarchical name space. In this design, uniqueness of names would easily be ensured. Data can be kept up-to-date much easier with local management and the implementation of zones of authority.