Domain Name System

The domain name system (DNS) is a name service that converts the known user domain (for example, “”) into the corresponding IP address. If you send the domain name as a query in the address bar, the domain is translated from the DNS to subsequently transfer the request to the appropriate server.

A domain consists of several parts:

  • DNS Root
  • Top level domain (TDL)
  • Second level domain (SDL)
  • One or more subdomains
  • Hostname

Top level domain

The top level domain, which represents geographic assignments (country code top level domain - ccTLD) is placed after the root level. Examples for this are:

  • de” for Germany
  • fr” for France
  • it” for Italy.

The TLD can also represent organizations.

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Second level domain

The second-level domain (SLD) appears in the hierarchy after the DNS root and TLD. It is usually the name of the service provided. Any combination of TLD and SLD must be unique worldwide. Examples of this can be seen above in the first graph.


All subsequent domains are subdomains. Subdomains can be, for example, an online store system under the domain (SLD) of your own website. This can be implemented any way you prefer. Examples:


Another use of subdomains is multilingual websites. That way you can divide your page clearly in different languages. The domains may look like this for the different pages:

  •” (German)
  •” (English)
  •” (French)