What is a DNS server and how does it work?

Imagine that the Internet is a huge city, full of buildings representing millions of websites. To find the address of each one, we need a guide to tell us how to get there. That role is fulfilled by the DNS, or Domain Name System, and DNS servers are the ones that make everything work without us even noticing.

A DNS server is a system that translates domain names (like cdmon.com) into IP addresses (like 46.16.58.60), which are the real codes that computers use to communicate with each other. This conversion happens in milliseconds every time you type an address into your browser. Without DNS servers, browsing the Internet would be like trying to call someone without knowing their number: impossible.

How do DNS servers work?

When you type a URL into your browser, a silent but fundamental process called «DNS resolution» begins. This process follows a series of steps:

1. Query the recursive DNS server: Your device asks a recursive DNS server (usually your Internet provider’s) if it knows the IP of the domain you’re looking for.
2. Ask the root DNS server: If the recursive doesn’t have the answer, it consults a root server, which tells it where to look next.
3. Query the TLD server: This server manages domains by extension (.com, .es, etc.) and knows who has the definitive information.
4. Query the authoritative server: This server has the exact IP address of the domain and returns it to your browser, which finally loads the web.

The circuit would be as follows:

1. We click on cdmon.com from our browser
2. The browser makes a request to the DNS server to find out which IP the domain cdmon.com points to
3. The DNS server returns the request with the IP associated with the domain
4. The browser makes the IP request to the server where it is hosted
5. The server returns the requested information and we can connect to the web hosted on the cdmon servers

All this happens in milliseconds.

Types of DNS servers

The DNS system relies on several types of servers that collaborate with each other to resolve domain name requests. Each has a specific role in the search chain, and understanding their differences is key to understanding the overall functioning of the system.

Recursive DNS server

It is the first server your browser contacts. Its job is to find the complete IP address, asking all the necessary questions until it reaches the authoritative server. It also caches the answers to speed up future queries.

Authoritative DNS server

It is the server that contains the final and definitive information about a domain. If you ask for cdmon.com, this is the one that has the correct and official answer.

Root DNS server

They are the starting point of the entire system. There are 13 sets of root servers worldwide, and their function is to indicate which is the appropriate TLD server for each query.

Relation with Browsing Speed

An efficient DNS can significantly improve the loading speed of a website. Why? Because it reduces the time it takes for the browser to translate a domain to its IP. Additionally, the use of cache in recursive servers avoids unnecessary searches and speeds up recurring visits.

Changing DNS server (for example, to a faster one than your ISP’s) can result in a much smoother browsing experience.

Common DNS Server Problems

Although robust, the DNS system is not perfect. Some of the most common problems are:

• Resolution errors: When the server cannot find the IP associated with a domain.
• DNS attacks (spoofing, DDoS): Malicious manipulations of DNS responses or server saturation.
• Propagation issues: When changing a domain’s DNS, it can take hours or days for the new information to update globally.
• Slowness or outages: A poorly managed DNS can cause even well-optimized sites to take time to load.

The DNS of cdmon

At cdmon we have a high-quality DNS infrastructure that guarantees speed, stability, and security. Our services include:

• High availability: Distributed and redundant server network.
• Optimized performance: Minimum response time thanks to strategically located servers.
• Advanced security: Implementation of DNSSEC to protect against manipulations.
• Easy management: Intuitive control panel to modify DNS records quickly and accurately.

If you wish, you can expand information about DNS servers in the following blog articles:

• DNSSEC: What is it and why is it important?
• How to check DNS propagation