DNS: The Domain Name System (DNS) is a fundamental component of the Internet infrastructure that plays a key role in translating human-readable domain names into machine-readable IP addresses. This translation process enables users to access websites, send emails, and engage in online activities without the need to remember the complex numerical IP addresses associated with each web server. In this article, we will learn in detail what DNS is and how it works to ensure uninterrupted connectivity on the internet.
What is DNS?
The DNS, or Domain Name System, serves as the Internet’s address book. Instead of requiring users to remember numerical IP addresses (for example, 192.168.0.1), DNS translates human-friendly domain names (for example, www.example.com) into IP addresses that computers can understand. and may use to locate websites and services.
How DNS Works: Process
User input: When a user enters a web address (URL) into their browser, such as “www.example.com”, the browser initiates a request to access that website.
Local DNS resolver: The user’s device sends a query to the local DNS resolver, usually provided by their Internet service provider (ISP) or a third-party DNS service.
Caching: The local DNS resolver checks its cache to see if it already knows the IP address associated with “www.example.com”. If this happens, the resolver returns the IP address directly, speeding up the process.
Root DNS server: If the IP address is not cached, the local resolver contacts the root DNS server. Root servers are the top-level servers in the DNS hierarchy and maintain information about top-level domains (TLDs) such as “.com,” “.org,” “.net,” etc.
TLD DNS Server: The root server provides a referral to the appropriate TLD DNS server based on the TLD of the requested domain. For example, if the requested domain is “www.example.com”, the TLD DNS server for “.com” is contacted.
Authoritative DNS Server: The TLD DNS server responds with a referral to the authoritative DNS server for “example.com”. The authoritative DNS server stores the unique IP address associated with the requested domain.
IP address retrieval: The authoritative DNS server sends the IP address of the requested domain back to the local DNS resolver.
Caching (again): The local DNS resolver caches the IP address for future use and sends it to the user’s device.
Website Access: With the correct IP address, the user’s device can now connect to the web server hosting “www.example.com” and the website’s content is retrieved and displayed in the user’s browser.
DNS is an important behind-the-scenes process that makes the Internet user-friendly and accessible. This enables users to interact with websites using familiar domain names rather than needing to remember numerical IP addresses. Understanding how DNS works empowers users to appreciate the complexity and efficiency of the Internet infrastructure. From simple domain queries to complex referrals between servers, DNS ensures that we can navigate the digital landscape seamlessly and effortlessly.