What Is DNS and How Does It Work?

DNS stands for Domain Name System. It is one of the most important parts of how the internet works, but most people only hear about it when something goes wrong. If you have ever connected a domain name to web hosting, set up business email, changed nameservers, added an SSL certificate or moved a website to a new host, you have already dealt with DNS.

In simple terms, DNS connects easy-to-remember domain names, such as example.co.uk, to the servers that store websites, handle email and run online services. Without DNS, visitors would need to remember long IP addresses instead of typing normal website names into their browser.

DNS can seem technical at first, but the basic idea is straightforward. Your domain name has records attached to it. Those records tell the internet where your website lives, where your email should be delivered, and which services are authorised to work with your domain.

What does DNS mean?

DNS means Domain Name System. It acts like a directory for the internet. People use domain names because they are easy to read and remember. Computers and servers use IP addresses because they need precise network locations. DNS connects the two.

For example, a visitor may type a domain name into their browser. Behind the scenes, DNS helps the browser find the correct server. Once the correct server is found, the website can load. This happens quickly and usually without the visitor noticing.

A helpful way to understand DNS is to compare it to a contact list on your phone. You tap a person’s name, but your phone uses their actual phone number to make the call. DNS works in a similar way. You type a domain name, but the internet uses DNS to find the correct server address.

Why DNS matters for your website

DNS is important because it controls where your domain points. If DNS is set up correctly, visitors reach your website, emails arrive in the right inbox, SSL certificates can validate, and connected services work as expected. If DNS is wrong, your website may not load, email may stop working, or visitors may be sent to the wrong place.

For small businesses, DNS is especially important because it affects trust. A customer may not know what DNS is, but they will notice if your website is offline, your emails bounce or your checkout does not work. Good DNS setup helps keep your online presence reliable.

DNS is also important when moving hosting. If you move a website to a new provider but do not update the correct DNS records, visitors may continue seeing the old website or may not reach the site at all. This is why tools such as our DNS Propagation Checker and DNS Lookup can be useful when checking domain changes.

How DNS works step by step

When someone visits a website, several DNS checks can happen very quickly in the background. The exact process can vary depending on caching and the visitor’s network, but the general flow is easy to understand.

1. The visitor types your domain name into a browser.
2. The browser checks whether it already knows the correct address.
3. If not, the request is sent to a DNS resolver, often provided by the visitor’s internet provider or public DNS service.
4. The resolver checks where the domain’s DNS records are managed.
5. The authoritative DNS server returns the relevant record, such as an A record.
6. The browser uses that answer to connect to the correct web server.
7. The website loads from the hosting server.

This process may sound long, but it usually happens in a fraction of a second. DNS is designed to be fast, distributed and cached so the internet does not need to repeat the full lookup every single time.

What are nameservers?

Nameservers tell the internet where your domain’s DNS records are managed. When you register a domain, it will use a set of nameservers. These may belong to your domain registrar, your hosting company, a DNS provider or another service.

If your domain is like a business name, the nameservers are like the office that keeps the official instructions for that name. They tell other systems where to find the DNS records for your domain.

Changing nameservers is a bigger change than editing a single DNS record because it can move DNS management from one provider to another. If you change nameservers without copying all existing records, services such as email, website hosting, verification records or third-party tools may stop working.

Common DNS record types

DNS records are individual instructions attached to a domain name. Each type of record has a different job. You do not need to memorise every record type, but understanding the most common ones makes it much easier to manage a website or domain.

A records explained

An A record is one of the most common DNS records. It points a domain or subdomain to an IPv4 address. If your website hosting provider gives you a server IP address, your domain’s A record can be used to point visitors to that server.

For example, your main domain might have an A record pointing to your web hosting server. When someone visits the domain, DNS returns that IP address, and the browser connects to the hosting server.

A records are often used when moving a website to a new host. Instead of changing nameservers, you may update the A record to point the domain to the new server. This can be useful if you want to keep DNS managed in the same place while changing only the website hosting.

CNAME records explained

A CNAME record points one hostname to another hostname. A common example is pointing www.example.co.uk to example.co.uk. This means the www version follows the main domain’s destination.

CNAME records are also used by many third-party services. For example, a platform may ask you to create a CNAME record to connect a branded subdomain, verify ownership or route traffic to their system.

One important point is that a CNAME record normally points to another hostname, not directly to an IP address. If you need to point directly to an IP address, an A record or AAAA record is usually used instead.

MX records and email delivery

MX records control where email for your domain is delivered. If you use professional email such as you@yourdomain.co.uk, your domain needs the correct MX records so mail knows where to go.

This is why email can break during hosting moves if DNS is changed carelessly. A website and email can be hosted in different places. You might have your website on one hosting platform and your email with another provider. If you change nameservers and forget to copy the MX records, email delivery may stop.

If you need email using your own domain, our Business Email Hosting page explains options for professional domain-based email. When setting up email, you may also need TXT records for SPF, DKIM and DMARC to improve authentication and reduce delivery problems.

TXT records, SPF, DKIM and DMARC

TXT records are flexible DNS records that store text information. They are commonly used for verification and email security. When a service asks you to prove you own a domain, it may give you a TXT record to add. Once added, the service checks DNS to confirm the record exists.

TXT records are also important for email authentication. SPF helps define which servers are allowed to send email for your domain. DKIM helps sign messages so receiving mail servers can check they have not been altered. DMARC tells receiving servers how to handle messages that fail authentication checks.

These records are not just technical extras. They can affect whether your emails arrive in inboxes, land in spam or get rejected. For a business that relies on email enquiries, invoices, quotes or customer support, correct email DNS records are very important.

What is DNS propagation?

DNS propagation is the process of DNS changes spreading across different networks and resolvers. When you update a DNS record, not everyone on the internet sees the change at the exact same time. Some networks may show the new result quickly, while others may keep using the old result until their cache refreshes.

This is why a website move can appear complete for one person but not another. You may see the new website on your office connection while someone else still sees the old site on mobile data. This does not always mean something is broken. It may simply mean DNS is still updating.

You can check DNS updates using our DNS Propagation Checker. This helps you see whether a domain record has updated across different locations. If you want to inspect specific records, use our DNS Lookup tool.

What is TTL?

TTL stands for Time To Live. It tells DNS resolvers how long they can cache a DNS record before checking for a fresh answer. A shorter TTL can make future DNS changes appear more quickly, while a longer TTL can reduce repeated DNS lookups.

TTL is especially useful to understand before moving a website or changing email provider. If you know a DNS change is coming, lowering the TTL in advance can help reduce the time old records remain cached. After the move is complete, the TTL can usually be increased again.

Not every DNS update is instant, even with a low TTL. Different networks and resolvers may behave differently. However, understanding TTL helps set realistic expectations when changing hosting, email or other domain services.

DNS and website hosting

DNS and website hosting are connected, but they are not the same thing. Your domain is the name people type. DNS tells the internet where that name should point. Hosting is the server space where the website files and databases live.

You can register a domain with one company, manage DNS with another, host the website with another, and use email with another. This flexibility is useful, but it also means DNS needs to be managed carefully. When something changes, the correct records must be updated.

If you are setting up a new website, start by choosing suitable UK Web Hosting. If your site uses WordPress, you may prefer WordPress Hosting. Once the hosting is ready, DNS records can be used to point your domain to the correct server.

DNS and SSL certificates

DNS can also affect SSL certificates. An SSL certificate helps your website load securely over HTTPS. Before many SSL certificates can be issued, the domain needs to point correctly or be verified through DNS.

If you have recently moved a website and the SSL certificate is not issuing, DNS may not have fully updated yet. The certificate provider needs to confirm that the domain points to the right place or that the required validation record exists.

Once SSL is active, visitors should be able to access your website securely. You can use our SSL Checker to check certificate details and expiry.

DNS and domain registration

Domain registration, DNS and hosting are often bundled together, but they are separate parts of your online setup. A domain registrar is where your domain name is registered. DNS is where the domain’s records are managed. Hosting is where the website lives.

You can register or transfer domains through our Domains page. Once you own a domain, DNS records decide how that domain behaves. This includes where the website points, where email is delivered and which external services can verify the domain.

WHOIS information is another part of the domain world. It can show registration-related details for a domain, depending on privacy rules and the domain extension. You can use our WHOIS Lookup tool to look up domain registration information.

Common DNS mistakes

Many website and email problems come from small DNS mistakes. A single incorrect character in a record can stop a service working. The good news is that most DNS issues can be fixed once you know what to look for.

• Changing nameservers without copying existing DNS records.
• Pointing the main domain to one server but forgetting the www version.
• Deleting MX records and accidentally breaking email delivery.
• Adding duplicate or conflicting records for the same hostname.
• Using an IP address where a CNAME target is required.
• Forgetting TXT records used for SPF, DKIM, DMARC or domain verification.
• Assuming DNS changes are instant everywhere.
• Not checking SSL after pointing a domain to new hosting.

Small business example: moving a website

Imagine a local accountant moving their website to a new host. The website uses the main domain for visitors, business email for enquiries, and a TXT record for a third-party booking tool. If they only update the nameservers and forget to copy the email and verification records, the website may move but email or booking features could break.

A better approach is to record all existing DNS records first. Then set up the new hosting, test the website, update the required A record or nameservers, check propagation, confirm SSL and test email. This careful process reduces the risk of disruption.

Small business example: setting up email

A small online shop may use one provider for the website and another for email. The shop’s website DNS records point visitors to the hosting server, while MX records send email to the mail provider. TXT records handle SPF, DKIM and DMARC.

If the shop later changes web hosting, the website records may need updating, but the email records may need to stay the same. Understanding this difference helps prevent downtime and missed customer messages.

How to check your DNS records

If you are not sure where your domain points, DNS tools can help. A DNS lookup can show records such as A, CNAME, MX and TXT. This is useful when checking whether a website points to the correct server or whether email records are in place.

Use DNS Lookup when you want to inspect specific records for a domain. Use the DNS Propagation Checker when you have recently changed DNS and want to see whether the update is appearing across different locations.

If your website is not loading, you can also use the Website Status Checker to see whether the site is responding. For HTTPS issues, use the SSL Checker.

Domain extension guides

DNS Connects Your Domain to Services

After choosing a domain extension, DNS records connect the domain to hosting, email and other online services.

Helpful domain guides

Compare Domain Extensions → .net Domain Registration → .org Domain Registration →

FAQs about DNS

Final thoughts

DNS is one of the hidden systems that keeps websites, email and online services working. Most visitors never think about it, but every domain depends on it. When DNS is correct, your website loads, your email arrives, SSL works and connected services can verify your domain.

The most important thing to remember is that DNS controls direction. It tells the internet where your domain should send website traffic, email and verification requests. Before changing DNS, always understand what each record does, make a copy of existing records and test everything after the change.

Whether you are launching your first website, moving to a new host, setting up business email or checking SSL, a basic understanding of DNS can save time, prevent downtime and make your website easier to manage.