What is Domain Name System (DNS)
The Domain Name System (DNS) is how human-friendly website addresses are linked to their equivalent machine-friendly destinations. Consider it something like a telephone exchange, except on a much more massive scale.
On the web, every single device must have a unique IP address. When you type in a simple address like Google.com, it is the DNS that translates that into an IP in order to see where the user is trying to go.
While that may sound simple enough, the way the DNS works is a little more involved. Let’s consider the steps involved.
How the DNS Works
As the name implies, the DNS isn’t a single component that does all the work, but a system. It comprises a few segments that each has their own role to play in domain resolution.
The segments involved in the process are the DNS Recursor, Root Nameserver, TLD Nameserver, and Authoritative Nameserver.
There are concrete steps in how these work sequentially:
- You type in the website address (for example, HostScore.com)
- That address is sent to a DNS Recursive Resolver (or simply DNS Resolver)
- DNS Resolver checks with a DNS Root Nameserver
- A TLD DNS Server address is sent to the DNS Resolver
- DNS Resolver sends a request to the necessary TLD
- The TLD Server sends the IP address to the DNS Resolver
- DNS Resolver then send the correct IP address of the website to your browser
To help you better understand the process, here’s a short description of what some of these things are and do:
- DNS Resolvers are designed to wait for queries from web browsers. When a query is received, it will then find the associated IP address.
- DNS Root Nameservers serve queries specifically in the DNS root zone. This network is made up of hundreds of servers around the world divided into 13 groups.
- Authoritative Nameservers hold DNS records for domains. It provides this information when queried about domain names in a zone.
- DNS Records contain information about domains such as the Address Record (A Record), Canonical Name (CNAME), and Mail Exchanger (MX Entry).
- TLD refers to Top Level Domain and is the topmost level of domain names.
As you can see, the process is relatively complex. However, it has to be in order to efficiently translate the massive number of IP addresses and domain names in existence. Today, there are over 1.7 billion websites in existence, with more being created each day.
For website owners however, an area of greater interest is normally the Nameservers. As with almost everything related to our websites, Nameservers come with varying performance profiles.
What are Nameservers?
Nameservers store the records our domain names are associated with. They are usually managed by domain name registrars or sometimes, web hosting services providers. Each Nameserver can store the information for many websites.
That’s why in a lot of cases, you’ll see many websites with the same Nameservers. For example, if you’re using a free Cloudflare account, chances are that your Namservers will be the same as hundreds of others;
Also, as you can see, each domain name needs a pair of Nameserver addresses for your website. This is redundancy in case a query fails to get a response from one address, then it’ll check with the secondary address.
DNS resolution typically only occupies a fraction of your website loading time. However, once you add up everything that contributes, it still remains one of the factors that you can actually improve fairly easily.