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What is DNS and How Does it Work?
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Ever wondered how the internet knows where to take you when you type in a website URL? Well, that's where the domain name system (DNS) comes in. Let’s break it down
By Virgin Media Edit
- Published
- 18 March 2025
What is a domain name system (DNS)?
The Domain Name System (DNS) is essentially the phonebook of the internet. It takes a website’s name (like www.virginmedia.com) and looks up the correct "phone number" (IP address) so your computer can connect to the right server and load the website when you click on it.
When you type a website address into your browser, your computer doesn’t actually understand what you’re typing in. The DNS translates this human-friendly website name into numbers that computers can understand so that your computer knows where to take you.
Without the DNS, you would have to memories long strings numbers for every website you visit rather than simply typing out its name. This would make it incredibly difficult to find websites without using a search engine, which is why the DNS is so fundamental to the internet as we know it.
How does DNS work?
When you type a website address like www.google.com into your browser, your computer needs to find out the correct IP address (a series of numbers like 142.250.190.14) to connect to that website. DNS helps your computer find the correct IP address by translating the website name into numbers that computers can understand.
The process usually looks something like this:
When you type a website address like www.google.com into your browser, your computer needs to figure out the correct IP address (like 142.250.190.14) to reach that website.
Computers use IP addresses to communicate with each other, but since it's hard for humans to remember numbers, DNS helps translate the website name into an IP address. This process starts when your computer sends a request to a DNS resolver (a special server that handles DNS requests) to begin the search for the correct IP address.
If the DNS resolver doesn’t already know the IP address, it sends the request to a root server. It doesn’t know the exact IP address of the website you want, but it knows where to find more information to find it.
The root server will direct your request to the correct Top-Level Domain (TLD) server based on the ending of the website address (like .com, .org, or .net). For example, if you are looking for google.com, the root server will tell the resolver to ask the .com server.
The DNS resolver then sends your request to the TLD server. The TLD server handles all domain names with a specific ending, like .com or .org. For example, the .com server manages all websites ending in .com. The TLD server will not know the final IP address, but it will know which authoritative name server has the correct information.
The DNS resolver now contacts the authoritative name server. In the case of google.com, the TLD server would point the resolver to Google's authoritative server, which is responsible for holding the exact IP address for the domain you are trying to visit. Google’s authoritative server will respond with the correct IP address (like 142.250.190.14). Now the DNS resolver has the information it needs to guide your computer to the correct location.
Once the DNS resolver gets the correct IP address, it sends it back to your computer. Your computer then uses this IP address to create a direct connection to the website’s server, which responds by sending the website’s data (like text, images, and videos) to your browser so that you can load the page. All of this happens in just a few milliseconds, so the process feels almost instant when you open a website.
The role of DNS servers
DNS servers are the individual computers or machines that perform the work of looking up and providing the correct IP address when you type in a website name. Without DNS servers, the DNS system wouldn’t work because the servers handle the actual process of searching for and delivering IP addresses.
When you type a website address into your browser, your computer sends a request to a DNS server (called a resolver), which contacts other DNS servers (like the root server, TLD server, and authoritative server) to find the correct IP address.
These DNS servers work together to track down the right IP address and send it back to your computer. Once your computer has the IP address, it connects to the website’s server, and the website loads.
DNS servers vs DNS: What's the difference?
The domain name system (DNS) is the overall system that manages the process of translating website names to IP addresses, while DNS servers are the machines that actually carry out this process. Think of DNS as the service (like the internet's phonebook), and DNS servers as the tools that do the actual job of looking up the numbers.
Types of DNS servers
1. Recursive Resolver
The recursive resolver is the first DNS server your computer contacts when you type a website name. Its job is to find the correct IP address by asking other DNS servers for help. If the recursive resolver already has the IP address stored (cached) from a previous request, it will give you the answer right away. If not, it will ask other servers (like the root, TLD, and authoritative servers) to find the answer. The recursive resolver handles all the back-and-forth communication, so your computer only has to wait for the final answer.
2. Root Server
The root server is the first step in finding the correct server. There are only 13 sets of root servers in the world, and they act like a directory for top-level domains (TLDs) such as .com, .org, and .net. The root server doesn’t know the final IP address of a website, but it knows which TLD server to ask next. For example, if you are looking for google.com, the root server will direct the request to the .com TLD server.
3. Top-Level Domain (TLD) Server
The TLD server handles all domain names that share the same ending, like .com, .org, or .net. When the root server directs the request to the TLD server, it helps narrow down the search. For example, if you want to visit google.com, the .com TLD server will direct the request to the authoritative server for google.com.
4. Authoritative Name Server
The authoritative name server holds the actual IP address of the website you’re trying to visit. Once the request reaches this server, it responds with the correct IP address. For example, if you are trying to visit google.com, Google’s authoritative server will respond with the correct IP address, like 142.250.190.14. This is the final step before your computer can connect to the website’s server.
5. Caching DNS Server
A caching DNS server stores (or caches) the IP addresses of websites that have been recently visited. This allows your computer to skip the full DNS lookup process if you visit the same website again. For example, if you visit google.com frequently, the caching server may already have the IP address saved, which speeds up the connection time. Cached data usually expires after a certain period, but it helps make internet browsing faster and more efficient.
How do DNS servers affect internet speed?
DNS servers can affect your internet speed because they play a key role in how quickly your computer can find the IP address of a website. Every time you type a website address (like www.youtube.com) into your browser, your computer has to contact a DNS server to find the right IP address.
When the DNS server responds quickly, the website will start loading faster, but when the DNS server is slow or overloaded, it will take longer to find the IP address, which makes the website load more slowly. Here's why:
If a DNS server is well-maintained and located close to you, it can respond quickly to your request. Some DNS servers also store (or cache) the IP addresses of popular websites. This means that if you visit a popular site like google.com, the DNS server may already have the IP address saved, so it can respond almost instantly.
Some DNS servers also cache information about websites they’ve already looked up, so they don’t need to search for it every time so that website load even faster.
If the DNS server is overloaded with too many requests or is located far from your location, it can take longer to process your request. This creates a lag between the moment you hit "Enter" and the time the website starts loading or even cause the website to time out or fail to load altogether.
Still, DNS doesn’t control the actual internet speed (measured in Mbps), just how quickly your connection starts working when you request a website or service.
If you’ve got issues with slow internet speed, upgrading to a faster broadband speed is usually the only way to fix it. Not sure what speed you’ve got? Use our helpful broadband speed checker to see if your broadband is up to speed.
Does DNS Matter for Streaming and Gaming?
For activities like streaming videos or online gaming, DNS speed matters even more than usually browsing. That’s because a fast DNS server means your device can quickly connect to the streaming or gaming server, while a slow DNS server can cause a delay in the data going to and returning from the server and your device, leading to buffering and lag.
Online games need to send and receive data constantly to keep the gameplay smooth. Before the game starts, your device contacts a DNS server to find the game’s server, and a slow DNS server can increase the time it takes to start the game or cause lag during gameplay.
How to improve DNS speed
You can improve your internet speed by switching to a faster DNS server. Many people use the default DNS servers provided by their broadband provider, but these may not always be the fastest.
If you think your DNS is too slow, you can try Google DNS (8.8.8.8) or Cloudflare DNS (1.1.1.1), which are known for being faster and more reliable. You may notice quicker website loading times and a more responsive internet experience.
Upgrade to superfast Virgin Media broadband
If your DNS is fast and you're still experiencing internet speed issues, the issue may lie in your broadband package itself.
The easiest way to supercharge your broadband speed is to upgrade your broadband package. At Virgin Media, we’ve got a range of broadband and TV packages to suit every speed and budget with speeds ranging from 100 mbps with our M125 broadband to gigabit and beyond with Gig 1.
Not sure what you can get? Use our helpful postcode checker to see what speeds are available in your area.
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