What is a domain name server

The Domain Name System is a directory service on the Internet. It is similar to a worldwide distributed telephone book in which one or more telephone numbers (IP addresses) are stored for a name. The DNS is therefore indispensable in order to be able to reach service offers on the Internet (e.g. online shopping or travel bookings). Because only with the DNS can you navigate to a website by entering a URL such as https://www.denic.de or sending an email to [email protected] The participants on the Internet are computers. In order to be able to communicate with each other, each computer has a unique IP address, e.g. B. 192.0.2.122 or even 2001: db8: 85a3 :: 8a2e: 370: 7334. The DNS maps the entered URL (e.g. www.denic.de) to this combination of numbers.

How does the DNS work?

The Domain Name System is a redundantly operated, hierarchical and decentralized system for managing names. It distributes the responsibilities and ensures the uniqueness of the names in the individual hierarchy levels. This is done using a tree-like structure of the namespace. The root of the tree ("root") branches into various sub-branches, the well-known top level domains such as B. .de, .net or .com. These in turn branch out into further sub-branches, the so-called second level domains, etc. (see figure).

The DNS does not only link computer names and IP addresses with one another. It also stores and outputs further information about the services that are linked to a domain. A DNS query can also be used, for example, to determine which computer is used as the e-mail server for the domain in question or what the name of the domain's name server is.