What is DNS?
A plain-English explanation of the Domain Name System — how it works, why it matters, and what it has to do with your website and email.
Every time someone visits your website, something invisible happens in the background. Their browser needs to find out exactly where your site lives on the internet. That process is handled by DNS — the Domain Name System. This guide explains what DNS is and why it matters for your business.
Quick summary
DNS is like the internet's phone book. It translates your domain name (like yourbusiness.com) into a number that computers use to find your website or deliver your email. When you move your website or change email providers, you update DNS records to point everything to the right place.
The simple version
Computers on the internet don't understand names like yourbusiness.com. They communicate using numbers called IP addresses (for example, 185.199.108.153). DNS is the system that translates one into the other.
Think of it like a contact list on your phone. You press "Call Mum" and your phone looks up her number. DNS does the same thing — you type a domain name and DNS looks up the IP address.
How a DNS lookup works
When someone visits your website, here's what happens behind the scenes:
The browser asks a DNS resolver. Your internet provider (or a service like Cloudflare or Google) runs a DNS resolver that handles lookups.
The resolver asks the authoritative nameserver. Your domain has authoritative nameservers — servers that hold the official DNS records for your domain.
The nameserver returns the answer. It tells the resolver: "This domain's IP address is 185.199.108.153."
The browser connects to that IP address. Your website loads.
This whole process takes milliseconds. You never see it happen.
What are DNS records?
DNS records are the individual instructions stored on your nameserver. Each record tells the internet something specific about your domain:
| Record type | What it does |
|---|---|
| A record | Points your domain to an IP address (your website server) |
| CNAME | Points one domain or subdomain to another domain name |
| MX | Directs email for your domain to your email provider |
| TXT | Stores text-based verification and security information |
See DNS records explained for a full guide to each type.
What are nameservers?
Nameservers are the servers that hold your DNS records. When someone looks up your domain, DNS knows to ask your nameservers for the answer. Your domain is pointed to a set of nameservers at your registrar, your host, or a service like Cloudflare.
Changing your nameservers points all DNS control to a new location. Changing individual DNS records makes smaller, targeted changes. See Nameservers vs DNS records for when to do each.
Why DNS changes take time
When you update a DNS record, the change doesn't happen everywhere instantly. DNS servers around the world cache (store) records for a set period — called the TTL (Time To Live). Until that cache expires, some visitors may still see the old setting.
This delay is called DNS propagation and usually takes anywhere from a few minutes to 48 hours. See DNS propagation: why changes take time.
What DNS has to do with email
Your email also relies on DNS. MX records tell the internet which servers handle email for your domain. SPF, DKIM, and DMARC records are security records that help ensure your email isn't marked as spam.
See Email DNS records for a full explanation.
Common questions
Related guides
- DNS records explained (A, CNAME, MX, TXT)
- Nameservers vs DNS records
- DNS propagation: why changes take time
- Email DNS records (MX, SPF, DKIM, DMARC)
- Common DNS problems & fixes
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