DNS resolution – Definition
The DNS resolution is a fundamental process that resolves a domain name to its IP address (IPv4 or IPv6). Without it, the entire Internet would work in a completely different way. However, it occurs behind the scenes because regular users don’t even notice that it is happening. People are used to typing a simple domain name, and the desired website is loaded in their browser. However, the user’s DNS query is actually traveling through several separate servers until it receives a full answer.
DNS resolution process explained
Regular users are used to connecting with their favorite websites in the blink of an eye. However, the entire DNS resolution process actually takes a long path. So, let’s’ explain a little bit more about the steps of this process, which begins with the user’s desire to visit a precise website for the very first time.
- The user makes a DNS query by writing the domain name into its browser’s address bar. That way, the DNS lookup for the needed IP address begins.
- The recursive DNS server obtains the DNS query and checks in its own DNS cache memory. The required IP address could still be available there. In case it is not found there, the recursive DNS server proceeds to the following steps.
- Тhe recursive DNS server proceeds and queries the Root server, which is on the top of the DNS hierarchy. The Root is able to provide information only for the location of the TLD (Top-Level Domain) server, such as .info, .net, .com, and so on.
- The DNS query is redirected to the TLD (Top-Level Domain) server responsible for the precise domain name. This server holds information about where is the needed name server for the domain.
- The recursive DNS server (DNS resolver) proceeds and requests information from the authoritative DNS server of the domain. This server carries the needed data (IP address) of the domain name, and it is the one capable of delivering an authoritative answer to the DNS recursive server.
- The recursive DNS server receives the information and contacts it back to the browser of the user. Additionally, it is going to store the IP address in its DNS cache memory to provide a quicker answer in the future.
- The user receives the IP address (IPv4 or IPv6), connects with the desired website, and caches it in the DNS cache.
So now you understand that the DNS resolution is an extensive process with several steps. Yet, at the same time, the user sees it as a few seconds.
Why is it important?
The DNS resolution process is crucial for humans. If it does not exist it would be a challenge for regular users to use the Internet and connect with their favorite websites. Back in the days when DNS (Domain Name System) did not exist, all IP addresses were saved in a single Host file. However, that was not practical anymore due to the fact that the devices wanting to connect to the Internet got a lot more.
Thanks to the development of DNS and the process of DNS resolution, we are easily accessing each website that we want by simply typing the domain name. We are not required to memorize complicated IP addresses.