What Is the Domain Name System (DNS)?

In today’s digital world, the internet has become an essential part of everyday life. We use websites, send emails, and interact on social media daily. Yet, few people consider how communication between our devices and remote servers works. In this article, we’ll explain in simple terms what DNS is, its role in internet functionality, and how it helps us seamlessly navigate the web.

DNS Basics

What is DNS? The Domain Name System (DNS) is a distributed hierarchical system that translates human-readable domain names into numerical IP addresses that computers use to communicate with each other. It is the backbone of the internet, making access to websites possible.

For instance, when you type www.example.com into your browser, your computer doesn’t inherently know where to send the request. DNS identifies the corresponding IP address, allowing your device to establish a connection with the correct server. In essence, the Domain Name System acts like the internet’s «phone book».

How Does DNS Work?

The operation of DNS involves several steps:

1. User Request: The user enters a domain name into their browser.
2. Caching: The computer checks its local cache for information about the domain.
3. Querying a Recursive DNS Server: If the information isn’t cached, the request is sent to the nearest DNS server, often provided by the user’s internet service provider.
4. Iterative Queries: The recursive server contacts root DNS servers, followed by top-level domain (TLD) servers (e.g., .com, .net), and finally the authoritative DNS server for the domain.
5. IP Address Retrieval: Once the chain of queries is complete, the recursive server obtains the IP address and relays it to the user.
6. Website Connection: The browser uses the retrieved IP address to establish a connection with the server hosting the website.

This process ensures quick and efficient internet navigation while hiding the complexity of network interactions from users. Without DNS, we’d need to memorize long numerical sequences instead of user-friendly domain names.

Types of DNS Records

DNS servers store various types of records that provide information about a domain:

• A Record (Address Record): Links a domain name to an IPv4 address, the most common type of DNS record;
• AAAA Record: Similar to an A record but for IPv6 addresses;
• CNAME Record (Canonical Name Record): Indicates that a domain is an alias for another domain;
• MX Record (Mail Exchange Record): Specifies mail servers responsible for receiving emails for a domain;
• TXT Record: Contains text information used for purposes like authentication and security (e.g., SPF, DKIM);
• NS Record (Name Server Record): Points to authoritative NS servers for a domain.

Understanding these record types is essential for managing websites, ensuring network security, and maintaining resource availability.

Types of DNS Services

There are several types of DNS services, each providing unique functions:

Using different DNS services optimizes network performance, enhances connection speed, and ensures security.

What Are NS Servers?

NS servers (Name Servers) are crucial elements in the Domain Name System. They store and provide information about which DNS servers are authoritative for a specific domain.

When registering a domain, you specify NS servers that handle queries for your domain. Proper configuration of NS servers ensures that users can access your website or other resources without issues. Changing NS servers can affect site availability, so it’s important to carefully manage updates and settings.

NS servers play a key role in managing DNS zones, which define responsibility for specific domain names. These zones contain all necessary records for a domain’s operation, including A records, MX records, and others.

FAQ

What is DNS caching?

DNS caching is a temporary storage of domain information on your device or server. When you visit a website, its IP address is saved in the cache. For subsequent requests, the browser retrieves the IP address from the cache, significantly speeding up page loading.

What is a DNS resolver?

A DNS resolver is a specialized server that translates human-readable domain names like www.example.com into IP addresses such as 142.250.186.142. When you enter a website address in your browser, your computer sends a query to the resolver, which then returns the corresponding IP address.

What is a DNS zone?

A DNS zone is a collection of records that map domain names to their respective IP addresses. Each zone corresponds to a specific top-level domain (e.g., .com, .ua) and contains information about all subdomains and resources associated with that domain.