Josua Schmid explaining the inner workings of the domain name system (DNS)

IP addresses

The internet works with IP addresses. Every computer has a number. Almost like a phone number. By the way, it really used to be a phone number. You may remember your first modem. First you dial in. Then you could exchange data. Today, it still works in a similar way.

Domain names

But since you can't remember numbers very well, you name them. In the past, a list of names was kept for each IP address on each computer.

In the long run, this is impractical. That's why DNS, the Domain Name System, was introduced. This is a distributed address book. From it you can find out which IP address you need to connect to, for example, if you want to visit the Renuo website

How it works

You enter a URL in the browser bar. Then the distributed address book is queried via a so-called name server. If the nameserver doesn't know the domain name yet (i.e. doesn't know which IP address belongs to the name) it has to query further up in the hierarchy itself. This can go up to the 13 world root servers. They then know in the last instance who is responsible for the name administration of the .ch top-level domain.

As soon as it is clear which IP address belongs to a domain name, the browser establishes a connection with the server hosting the website.


Domain names are in the memory of people and programs (including web links) and are therefore valuable. It is important to know who owns a domain and who exercises control over it. The administrative hierarchy for domain names can be viewed in two strands of control: administrative and technical

Administratively at the top of the Internet is the American-based global organization ICANN. According to the dotted line, it delegates rights and duties to OFCOM for the .ch top-level domain. Further down is the company Renuo as owner of the domain

Technically, IANA takes care of the central servers of the domain name system. It cedes the technical administration of the ch domain to Switch. The operations team of Renuo then takes over the technical responsibility of

The registrars are still administratively interposed in an intermediary role. They forward administrative matters automatically (and manually) to OFCOM.


One could think that DNS loses relevance in the age where you ask Google anyway, because Google shows you the content without you having to enter a URL in the browser bar. However, Google is also only a very well organized list of names. And if these names no longer point to the right place, real life may become dangerous. The media once circulated a picture from Turkey describing which DNS server (,, you have to enter on your own computer in order to circumvent state censorship.

This political discourse is also being played out in Switzerland as "deleting instead of blocking". Some say that a censorship apparatus is necessary because deleting at the source is a Sisyphean task. The others do not want a censorship apparatus at all. It is important to know: since the casino vote, there is a legal basis for "blocking" in Switzerland.