DNS

Since its invention the main purpose of the Domain Name System (DNS) has been the “translation” of a logical domain name like www.hs-offenburg.de into an abstract and unique IP-address, similar to a phonebook, where all names are related to a unique phone number. Today DNS is a hierarchic database, distributed worldwide on thousands of name servers, administrating the internets’ namespace. Before the release of DNS every new computer joining the ARPANET received a file called HOSTS.TXT from SRI, containing all numeric addresses (z.B. 141.79.128.3) of all computers with the corresponding name (z.B. www.hs-offenburg.de). In the long run this system was not suitable for ARPANET, due to its rapid growth.

In search of a better system Paul Mockapetris wrote the first DNS implementation in 1983. One year later four students from Berkeley published the first UNIX-based implementation.
A domain name (hs-offenburg.de) consists of at least two parts, a top level domain (.de, .com, .org) and at least one sub domain (hs-offenburg). In „mi.hs-offenburg.de“ for example, the “mi” part would be a sub domain within the domain „hs-offenburg.de“. In order to interpret the domain name the software has to go through it segment by segment from right to left.

DNS in MI-Learning Computernetze
(in German)