What is DNS? Domain Name System Explained

January 9th, 2021

What is DNS? Domain Name System Explained

What is DNS?

When the internet was just a baby, a human user would easily match an IP address to a specific computer. To access the internet, you would type IP numbers such as 92.268.0.1 into your computer.

This didn't last as long as the number of networked computers increased. Today, although you can still use an IP address to access a website, DNS makes life easier with human-relatable addresses such DNSexamples.com. DNS is a directory of names and web addresses that matches with numbers and IP addresses.

Computers communicate with each other via IP addresses. Humans communicate to computers via domain names. DNS translates a given domain name into an IP address so that a web browser can send a question to servers and find and return answers.

How does DNS work?

DNS saves you from having to remember and type in a browser IP addresses, which have become super complex today. Look at how crazy IP addresses can look: "2001:0db8:0000:0000:0000:ff00:0042:7879."

Through the process of DNS resolution, DNS converts a hostname such as www.DNSexample.com into a machine-friendly IP address such as 12.244.233.165.

Each device connected to the internet has an IP address. The numbers above help find the right device, just like a building's street address in a local directory. Another good example is the contact list on your phone. It matches names of persons to numbers so that you only have to remember names instead of memorizing numbers.

DNS Resolution

Every time you load a webpage or open an email, a translation occurs between what you enter in your web browser and the IP address needed to locate your requested resource.

There is a universal DNS directory which, like the phone book app on your mobile device, matches (domain) names to (IP) numbers. Except in this, the directory is not stored in a single device. It is globally distributed and stored on DNS servers.

When you enter www.DNSexample.com into your web browser, the DNS Resolver first searches for the hostname in the local cache. If it isn't there, the resolver routes the request through many DNS name servers until it gets the IP address of the website you have requested. This is the DNS resolution process, and often it happens in mere seconds.

The resolution process is a coordinated effort between these DNS servers:

  • DNS resolver
  • The root server
  • TLD name server and
  • Authoritative name server

The Four Most Crucial DNS Servers

1. DNS Resolver

When you type and search for something in a browser, your device's first command is to find the IP address for the domain name. The device starts by connecting to the DNS resolver, also known as a recursive server.

The recursive server is the first gate to the internet and might be manned by your internet service provider, whether mobile or WIFI. The server is well connected to other DNS servers, and once allowed connection, it sends the request to a DNS Root Server then receives details of a TLD Name Server.

2. Root Server

The root server is a reference that functions in a similar manner to a library index, showing you where each book is located. After receiving the resolver's request, the root server responds with details of a TLD server, the host's specific location.

3. TLD Name Server

In www.DNSexample.com, the last part, .com, is the Top-Level Domain. The TLD server takes the query and provides details for the TLD. Think of the TLD server as the specific shelf of books in a library. It contains all the records for the requested host.

There is a specific name server for each TLD. As at now, there are more than 1500 TLDs including .com .org .biz .gov and country-specific TLDs such has co.uk.

4. Authoritative Name Server

The last step in resolving a query is the authoritative name server. If this server has access to the requested resource, it returns an IP address with a hostname back to the DNS resolver.

Summary of DNS resolution

The process starts with the DNS Resolver and ends at the Authoritative name server. The process entails requesting the matching IP address and location for a human-readable domain name.

Top-Level Domain servers play a critical role in the resolution. The request bounces from the librarian (the DNS resolver) to the index (the root server) and the specific bookshelf (the TLD server).

The TLD name server resolves the query by referring it to the Authoritative Nameserver responsible for the domain. This is the server that knows the IP address for the domain.

DNS in a nutshell

DNS service translates domain names to specific IP addresses to enable internet searches. DNS service providers optimize the process of DNS resolution via multi-server hosting in diverse geographic locations. DNS hosting improves the performance and security of client-server-network communication.