Domain Name System (DNS)

DNS (Domain Name System) is a naming system that translates human-readable website addresses (for example, example.com) into numerical IP addresses required by computers to exchange data over a network. DNS functions as the “phone book of the internet,” ensuring fast and accurate connections between users and servers.

What is DNS

The abbreviation DNS stands for Domain Name System. Its primary function is to map domain names to IP addresses. When a user enters a website address in a browser, the DNS system determines which server hosts the resource and directs the request to the correct destination.

Without DNS, users would need to remember long numeric addresses (such as 192.168.1.1), making it one of the core technologies that ensure the usability and accessibility of the internet.

How DNS Works

DNS operates on a multi-level hierarchical structure of servers that process user queries step by step:

1. Recursive query – when a user enters a domain, the browser contacts a local DNS server (usually operated by the ISP or the operating system).
2. Root DNS servers – if the record isn’t found locally, the query is forwarded to one of the root servers, which point to where the top-level domain (TLD) servers are located (e.g., .com, .ru, .org).
3. Top-Level Domain (TLD) servers – these direct the query to the authoritative servers responsible for the specific domain.
4. Authoritative DNS server – this server contains the precise record of the domain and returns the corresponding IP address.

Once the IP address is obtained, the browser connects to the appropriate server, and the DNS client caches the result for faster access next time. The system is globally distributed to ensure fault tolerance, speed, and load balancing across millions of domains.

Use Cases

DNS is used in all types of network interactions where fast and reliable address resolution is required:

• Web infrastructure – routing user requests to websites, APIs, and cloud services.
• Corporate networks – managing internal domains, load balancing, and enhancing security.
• Cloud and CDN solutions – distributing traffic geographically and improving response times.
• Security systems – filtering malicious domains and protecting users from phishing attacks.

Providers and data centers often operate their own DNS servers to manage client domains, maintain website stability, and minimize latency.

Advantages

The DNS system makes the internet scalable, user-friendly, and secure. Its key advantages include:

• Simplified navigation – users interact with readable domain names instead of numerical IP addresses.
• Flexibility and scalability – administrators can change routes or servers without disrupting website availability.
• Reliability – the distributed DNS structure ensures resilience even if some servers fail.
• Security – technologies like DNSSEC (Domain Name System Security Extensions) protect users from data spoofing and redirection to phishing sites.

DNS also contributes to faster website loading by caching and distributing requests to the nearest servers.

Example

A user enters company.ru in their browser. The ISP’s recursive DNS server sends a query and receives the IP address of the hosting server. The browser then establishes a connection, and the page loads. On subsequent visits, the cached record allows for much faster access.

For corporate clients, a service provider can configure a dedicated DNS to manage subdomains, redirects, and traffic balancing between data centers.

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