Categories
DNS

DNS: What is it?

DNS is a complex topic, and it deserves special attention. A long time ago, there was no Internet. However, today we can not imagine the world without it, and DNS is one of its main pieces. So let’s explain a little bit more about it. 

What does DNS mean?

DNS stands for Domain Name System. It is an essential part of the Internet that serves a great purpose. This infrastructure makes the experience on the Internet for humans simple and easy. The functionality it provides is enormous. At its core, the DNS has a large database with the existing domain names and the IP addresses that correspond to them.

If you are searching for detailed information, check the following article about the Domain Name System!

When you want to visit a website, you type the website’s domain name. That triggers an extensive DNS process. This domain name has to be translated to a language that machines understand (IP addresses). That action is necessary to achieve successful communication between the machines. When the domain name that is requested is finally associated with the required IP address, it is sent to the user’s browser. Then, the website can be loaded and reached successfully.

In the days before DNS was created, it was necessary to enter the IP address and not a simple domain name. Imagine what a challenge that was! DNS provided easy communication between humans and machines.

The hierarchy

The Domain Name System is constructed hierarchically. The separate levels are responsible for the different essential parts.   

  • On the highest DNS level is the Root level. That is the place where the root name servers exist. It is represented with a dot at the end. (examplesite.com.)They are the first move for resolving a domain name. These root name servers hold the world register of top-level domains. 
  • The Top Level Domain (TLD) is the next level below the Root one. Here exist various TLD servers. Each of them is responsible for the different TLDs, such as .com, .org, .net, .eu, and so on. This level is expressed with the extension of the domain. (examplesite.com)
  • The next level below is the Second Level Domain (SLD). The Second Level Domain is ordinarily the part of the URL that identifies the domain name of the website. (examplesite.com)
  • One level down is the Subdomain. These are the further components of the domain name. They are beneficial for the organization and could navigate through several sections of the website. (blog.examplesite.com)

What is a DNS lookup?

DNS lookup is a searching process. It repeats millions of times every day.

This process begins when a visitor enters a domain name on the browser. On the other hand, it makes a request to a recursive DNS server wanting DNS information, such as IP address and DNS records. 

The recursive server is going to check for that data in its cache. If it is still there, it will answer with it the query. In case it is not, the recursive server will proceed with asking the root server. The root is going to show the accountable Top Level Domain (TLD) nameserver for that specific domain. Next, the recursive is going to request from the TLD server to point to the authoritative nameserver that is for the exact domain. Finally, the recursive server will receive from this last server the requested IP address.

The recursive server gets back to the browser with the IP address, and the website can be reached.

Actually, it takes a lot more time to explain it, rather than for it to happen!

Suggested article: DNS Load balancing explained

Leave a Reply

Your email address will not be published.