26 May 2021

Domain Name System (DNS)

 Domain Name System

The Domain Name System (DNS) is one of the foundations of the internet, yet most people outside of networking probably don’t realize it. As they use it every day to do their jobs, check their email or waste time on their smartphones. It is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet. It associates various information with domain names assigned to each of the participating entities.

Each device connected to the Internet has a unique IP address which other machines use to find the device. DNS servers eliminate the need for humans to memorize IP addresses. It ensures the Internet is not only user-friendly but also works smoothly, loading the content users ask for quickly and efficiently.

How Does DNS Work

DNS is the cornerstone of how the Internet operates. Computer refers to a DNS server to find the corresponding IP address, every time you type a domain name into your browser. Let say you type a domain into your browser, such as example.com your computer will use a DNS server to resolve the IP address of that website’s server.

Once the IP address is  identified, your computer contacts the website’s server, which in turn serves your computer the website that you want to access.

The DNS Network

This is a database of website domains and IP addresses. Its key function is to store the data and link the domain names and IP addresses when requested. It includes other functions such as:

  1. Domain Namespace Hierarchy; this enables a user to quickly find the correct server that hosts the DNS records that they require.
  2. Distribution; here each server holds a small portion of data that are distributed over a vast network of connected servers.
  3. Record Maintenance; the process involves locating IP addresses connected to domain names and storing this data.

Domain Namespace

This is the hierarchical structure of the DNS servers.

DNS structure

The DNS Hierarchy

When you type a domain name into your browser, the computer checks cache to see if it has previously requested that domain name. DNS server receives a request when there is no record. The local DNS server checks to see if it has any records in its cache. If not, it locates the details of the name server that hosts the domain record for that particular domain.

In order for this to happen, the local DNS server breaks the domain name into sections. For example, www.domain.com.

  • com
  • domain
  • www

The ‘com’ section is known as the top-level domain (TLD). First the local DNS server will connect to a root name server to find details of the server that holds the domain info for this TLD. Once the TLD name server IP address is identified, the local DNS server will make a request to this new server to find out which name server holds details on the second part of the domain name (i.e. domain).

The local DNS server makes further requests for the name servers that contain data on domain.com and the www.domain.com, working down until the IP address is resolved. Your browser can then use this IP address to contact the server hosting the website. Need a domain? click here to get in touch with us and register.

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