What does DNS resolution mean?

The DNS resolution happens daily, and we don’t even notice it. So let’s explain a little bit more about it.

DNS resolution explained.

The process of DNS resolution is triggered by typing a domain name into the browser. Thanks to it, the domain names are quickly and easily translated to IP addresses. 

A particular domain name could have more than one IP address, for instance, one IPv4 address and one IPv6 address. Then the DNS resolution is going to proceed for both of them. However, in order to connect with the domain, we are going to need only one of these addresses.

The quick way for translating domain names become a necessity long ago. Back in the day, every existent IP address was saved in a Host file that was updated manually. But, as you know, the number of devices has increased tremendously, until, at some point, it was not effective anymore to search for IP addresses that way.

The Domain Name System (DNS) was launched, and the search and the Internet became a lot easier. The user only has to type the domain name, and it simply reaches the website. It is something we don’t even understand how quickly happens.

How does it work?

The DNS resolution follows several steps. The process begins when a user desires to visit a particular website for the first time. 

  1. The user types a domain name in their browser, and this is the beginning of the DNS query. The process of a DNS lookup is triggered, which is going to start seeking the required IP address of the domain name.
  2. The first stop of the DNS query is a DNS recursive server. This server is going to scan for the needed information (IP address) inside its cache memory. Afterward, it is going to interact with the other DNS servers to find and provide to the client the needed answer. The first server that the DNS recursive server is going to communicate with is going to be the Root server.
  3. The Root server is on the top level of the DNS hierarchy. It is going to view the Top-Level-Domain (TLD) extension of the queried domain name, for instance, .net, .info, .eu, etc. Then it is going to provide information about the location for the exact TLD server and redirect the query to it.
  4. Next, the recursive DNS server is going to interact with the TLD server for the specific domain name. The TLD server is going to give a response with the right nameserver for the domain name.
  5. Again, the recursive DNS server has to make another lookup and communicate with the authoritative DNS server for the domain name. Since it is authoritative for the inquired domain name, it is the one storing the IP address of the domain name and answers the query.
  6. After the recursive DNS server receives the answer, it transfers it to the user. In addition, it will keep it inside its cache memory for further usage.
  7. Finally, the user accepts it and also stores it in its cache memory. Then, it can, with the provided IP address, reach the website.

The user experience is just a brief moment of waiting, yet the DNS resolution process takes a lot of steps, and the DNS query proceeds through a number of servers on the way.

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