General
People write website addresses in text, but computers communicate with each other using numbers. The solution to this communication problem is DNS (Domain Name System), the Internet’s name service system that converts web page addresses such as resources.crmservice.com into a form that computers can understand, i.e. IP addresses. It is a kind of Internet telephone directory that allows a computer to match the address of a web page you enter with the correct destination based on the number.
DNS is an important part of any website. To ensure the safe delivery of your emails, you need to update the DNS TXT record of your website. For more information on this topic, see the article Managing and checking DNS records.
So how does DNS work?
The purpose of DNS is to direct a visitor to a website to the right place by converting the name into numbers that other computers can read. So when you type the address of a website into the address bar of your browser, the following sequence of events occurs:
- Once the website address is typed into your browser’s address bar, a DNS query begins, looking for the IP address corresponding to the address you typed.
- The query is routed to global root servers that know the DNS information for all domains in the world. This information is verified and used to determine the next TLD name server check.
- The TLD name server is the domain name extension, which can be the extension of a specific country such as .fi in Finland and .se in Sweden, but it can also be the commonly used extension .com, .org or .net. So, for example, if you search for example.fi, the .fi TLD name server will be used to search for the name servers of the domain name of the example.fi website. In the case of the example.com site, the .com TLD name server would be queried.
- The domain name server is the location where the DNS zone file for the desired website is located. This zone file in turn contains all the individual DNS records, such as the DNS TXT record and the various sub-domains, such as support.example.fi in the case of ww.example.fi. The initial query looks up the IP address from the A record that lists the IP addresses, from which the computer then retrieves the content of the website example.fi and displays it in your browser.
This whole process happens very quickly and also sounds very technical, so let’s break this process down into a more understandable form with an example.
DNS example
You know you want to go to Example (example.fi) and reach customer support at Ess (support.example.fi), but you don’t know where Ess’s office is. However, you know that there is an information point where you can ask.
- You go to the information desk and give the receptionist (address field in your browser) the details of Ess (tuki.esimerkki.fi). The receptionist will give you a contact number (IP address) and you will be directed to the waiting room.
- The contact number will take you to the receptionist (root server), who will check your details and tell you that you can get help from the Info Point’s Finland section, which has information on all Finnish (.fi) companies.
- You go to the Info-Point’s Finland department (TLD name server for .fi addresses) and they will retrieve your company details and direct you to the right address in the company’s office located in Helsinki.
- Finally, you arrive at the company’s office (example.fi) where a receptionist (DNS zone file) is waiting for you. When you tell them who you want to speak to, the receptionist will look at Essi’s details and tell them which floor and room (support.example.fi) Essi is on.