Definitions of domain name and internet terms

Country Code Top Level Domain ccTLD



Domain Name System. Computers that are connected up to the internet communicate with each other by means of the Internet Protocol (IP) and have at least one IP address that identifies their computer on a unique basis. This is a number in the format or 2001:db8::37. Since it is difficult to remember numbers of this type, the "Domain Name System" DNS was developed, which allows users to employ words or names in the internet. This means that the website of SWITCH, for example, can be accessed not only via the IP address of its webserver, but also via the domain name A further advantage of the DNS is that the domain name remains the same even if the IP address of the webserver is changed (such as in the case of a provider change).

The name space in the DNS has a hierarchical structure; the convention is for the individual levels of the hierarchy to be separated by dots and for the highest level to be written on the far right.

The domain name is translated into the corresponding IP address of the target computer by the name servers. This is done in the manner set out in simplified terms below (taking the example of a .ch domain name). For a domain name to work in the internet, there must be at least one name server which can provide information on the IP address of the computer on which services such as WWW or e-mail are running. These name servers must be entered, together with the domain name, in the zone file for the Top Level Domain ch. This is done automatically once these name servers have been entered for the corresponding domain name in the SWITCH database. If the domain name is now called up in the browser, enquiries are submitted to the name servers for the Top Level Domain ch. These pass on the enquiry to one of the name servers that has been entered for this domain name, which then sends back the IP address of the webserver. The browser now has the IP address of the server it was looking for, and can request the desired document from this server.

See also Domain name, Name server, IP address


DNSSEC is an extension of the Domain Name System (DNS), that ensures the authenticity and integrity of the data in DNS replies. More about DNSSEC

Domain Name

Domain names are an addressing method used to identify computers in the internet. They make it possible for users to employ words and terms instead of rows of figures (IP addresses).

See also DNS, IP address


A network protocol for transferring files over TCP/IP networks. This is used to transfer files between computers via the internet, such as for transferring the files for a website to the webserver.

Generic Top Level Domain gTLD



The natural or legal person in whose name a domain name is registered.

Hosting, Webhosting

Webhosting or hosting is the term used for accommodating a website on a provider's server that is connected up to the internet. The webhoster is a service provider who makes memory space available on a server for the files that make up a website. Customers can administer their own data there.

See also FTP

Host Name

The host name is the name that unambiguously identifies a computer in its network. In a URL, the host name comes straight after the designation of the protocol and before the domain name. In many cases, the host name is allocated according to the purpose for which the computer is used. The most familiar example of this is the "www" in URLs. This designation has become established as the host name of the computer on which the WWW service runs, i.e. the webserver. Whether a website is called up with or without the www in front of the domain name will depend on the configuration at the provider's (sometimes both are possible).


Internet Assigned Numbers Authority. An organisation which organises the allocation of IP addresses, Top Level Domains and IP protocol numbers. IANA is a sub-department of ICANN in organisational terms.


Internet Corporation for Assigned Names and Numbers. ICANN coordinates the allocation of the following designations, which need to be unique worldwide for the internet to function:

  • domain names
  • IP addresses
  • protocol parameters and port numbers

ICANN additionally coordinates the stable operation of the Root Name Server System in the internet.


Internationalized Domain Names. These are domain names which are permitted to contain characters other than the ASCII characters allowed to date, including characters with umlauts and accents. A standard has been introduced for depicting domain names which contain non-ASCII characters in the form of valid ASCII strings.

More about domain names containing accents and umlauts

IP, IP Address, IPv4, IPv6

IP is the abbreviation for Internet Protocol, a network protocol that is widely used in computer networks. IP addresses allow the logical addressing of devices (hosts) in IP networks such as the internet. A host has at least one unique IP address. An IP address written in IP Version 4 generally takes the form of a sequence of four numbers, each separated by dots, e.g. IPv6 (Internet Protocol Version 6) is the successor to Version 4. IPv6 addresses are 128 bits in length (IPv4 addresses: 32 bits). This considerably extends the number of addresses. Example for a IPv6 address: 2001:db8::37.

The IP address space is currently administered worldwide by five Regional Internet Registries (RIRs): RIPE NCC, ARIN, APNIC, LACNIC and AfriNIC. The RIR responsible for Europe is RIPE NCC, which is based in Amsterdam. RIPE NCC allocates large address blocks to its members, the Local Internet Registries (LIRs). These are local Internet Service Providers who, in turn, allocate IP addresses to their customers.

See also DNS

Name Server (Domain Name Server)

Name servers are an element of the DNS and administer the information about which IP addresses belong to which domain names. If the URL of a webpage is entered into a browser, a name server is required to supply the corresponding IP address so that the browser can establish a direct link with the page.

To ensure that a domain name will work in the internet, at least one name server must be configured for this domain name and entered in the registry's database and in the zone file.

See also DNS, IP address, zone file


Swiss Federal Office of Communications, the regulatory authority for domain names ending in .ch.

Office for Communications

Regulatory authority of the Principality of Liechtenstein for domain names ending in .li.


An Internet Service Provider (ISP) provides access to the internet (also known as an Access Provider). The majority of Providers also offer services associated with domain names and an internet presence (Hosting Providers).

Registry and Registrar

A registry is an organisation that administers the Domain Name System (DNS) for a particular country. It is responsible in particular for registering domain names with the corresponding country code Top Level Domain (ccTLD). SWITCH is the registry for Switzerland and Liechtenstein. It was contracted by OFCOM in Switzerland to register domain names ending in .ch and by the Office for Communications in the Principality of Liechtenstein to register domain names ending in .li.

A registrar is a company that has signed a contract with a registry (e.g. SWITCH) and offers its customers a range of services including domain name registration. The registrar is thus a resale partner of the registry.

List of accredited registrars


Réseaux IP Européens. A community of different organisations and individuals who operate IP networks in Europe and beyond. The aim of this community is to ensure the administrative and technical coordination required for the operation of the IP networks. The RIPE members operate the RIPE NCC (Network Coordination Centre) to this end, which holds responsibility for the allocation of IP adresses within Europe, among other things.

Second Level Domain

The second-highest level of the hierarchy in the DNS. In a URL, the Second Level Domain is positioned to the left of the Top Level Domain. SWITCH administers the Second Level Domains under the Top Level Domains ch and li.

Technical Contact

The private person or legal entity that is entered as the person responsible for technical matters for a domain name.

Top Level Domain TLD

The top level of the hierarchy in the DNS. In a domain name, the Top Level Domain is positioned on the extreme right. A distinction is drawn between general TLDs (Generic Top Level Domains, gTLDs) and country-specific TLDs (Country Code Top Level Domains, ccTLDs). Examples of gTLDs are com (commercial), org (organisation), and net (network). Examples of ccTLDs are ch (Switzerland), li (Liechentstein), de (Germany), fr (France), it (Italy). The designations of the ccTLDs are based on the standard ISO-3166.

See also Second Level Domain

List of all Top Level Domains compiled by IANA

Transfer and Transfer code

Transfer: When a domain name is transferred, responsibility for administering it passes from one registrar to another.

Transfer code: A transfer code is needed to transfer a domain name from one registrar to another. You can ask your current registrar for a transfer code and then forward it to the new registrar.


Uniform Resource Locator. A standardised method for locating resources in the internet (such as a webpage). URLs identify a resource via the access mechanism (transfer protocol, e.g. https) and the file location. A URL can thus be regarded as the address of a document.

In the example, "https" is the transfer protocol, "www" the host name, "" the domain name, and "/about/index.html" the path and the name of the document required.

Website, Webpage

A website denotes an internet presence in its entirety. A webpage is an individual page of the website.


A webserver is a program or a network service on a computer that is connected up to the internet (server) and which supplies the desired documents (e.g. a webpage and the graphics on it) when so requested (by a browser, for instance). One familiar webserver is the Apache HTTP Server.

The computer on which the webserver software or the WWW service runs, and on which the files for the website are located, is also called a webserver.


World Wide Web, the most well-known internet service today. The WWW information system based on hypertext was developed in 1992 by Tim Berners-Lee of the CERN nuclear research institute in Switzerland. Hypertext is a network-type structure of texts and other contents that are joined to each other by means of cross-references (hyperlinks). Hypertext documents have an address (URL) to identify them within the internet. This gives each individual document its own unambiguous designation within the internet. The documents can contain not only text but also multimedia elements, such as pictures, and video and audio information.

www (in the URL and in the internet address)

See Host name

Zone File

The zone file for the Top Level Domain CH contains a list of all the active .ch domain names with details of the competent name servers. The zone file is located on the name servers for the TLD CH. The same applies for the TLD LI. The information concerning the name servers for the individual domain names comes from the SWITCH database. The zone file is updated on an hourly basis.

The zone file for CH is publicly available. For more information, visit SWITCH's Open Data web page.

See also DNS