Short answer: DNS, the Domain Name System, turns a domain name into the address of the server behind it, like a phone book for the web. Your DNS records decide where your website, your email and your verifications point, and each change takes effect within the record’s TTL.
What DNS does
MDN describes DNS as a hierarchical and decentralized naming system. Its best-known job is the DNS lookup: turning a name such as a domain into the numeric IP address of the computer that hosts it.
Domain names exist because people can’t remember those numbers, and MDN notes that IP addresses can change over time. Google’s help calls DNS the phone book of the web. Our domain name guide covers how to choose one.
Your domain’s records live with the company that runs its DNS, often the registrar or your host. Our web hosting guide explains the server those records point to.
The DNS records that matter for a business
| Record | What it does | Typical use |
|---|---|---|
| A | Links a name to the address of the server that hosts it | Your website on its host |
| CNAME | Makes one name an alias of another | www pointing at your main domain |
| MX | Sends your domain’s email to the servers that hold your mailboxes | Your email provider |
| TXT | Holds text that outside services read | Domain verification, SPF, DKIM and DMARC |
| NS | Says which servers answer for your domain | The company that runs your DNS |
From Google Workspace Help’s DNS basics, read November 4, 2026.
A domain can have several MX records, each with a priority, so mail goes to the next server if the first can’t take it. TXT records also carry your email’s security settings, which our SPF, DKIM and DMARC guide covers.
How long DNS changes take
Every record has a TTL: the number of seconds before a change to it takes effect, because servers keep the previous answer that long. Google’s help gives the example of a TTL of 86,400 seconds, where a change can take up to 24 hours.
Google suggests 3,600 seconds while you work on your records, 300 seconds before a change you might want to undo quickly, and 86,400 once the records are configured correctly. A shorter TTL only works once the old period has run out.
How to change a DNS record safely
- Find out who runs your DNS: your name server records show it.
- Copy every current record before you change anything.
- Lower the TTL of the record you will change to 300 seconds, a day ahead.
- Make the change: A for a new host, MX for new email, CNAME for an alias, TXT for a verification.
- Check the new answer from a public resolver or a DNS lookup tool.
- Open your site and send a test email to and from your domain.
- Raise the TTL to 86,400 seconds once everything works.
When you move to a new host, the A record is the one that changes; our website migration guide covers the rest of that move.
Our own domain’s records
We read our own domain from a public resolver on November 4, 2026. It has one A record, pointing at our web server, with a TTL of 300 seconds. Google suggests that value around a change and 86,400 once records are configured correctly, so ours is set for a quick change. www is a CNAME, an alias of the main domain.
Two MX records send our email to our mail provider. Of the three TXT records at the root, one is our SPF policy and one verifies the domain for Google. A separate DMARC record tells receivers to reject mail that fails the checks.
Four name servers answer for the domain, each with a TTL of 86,400 seconds: the example Google gives of a change that can take up to 24 hours.
Before and after a DNS change
- You know who runs your DNS.
- You have a copy of every record.
- The TTL is short before the change.
- The site opens on the new address.
- Email arrives in both directions.
- The TTL goes back up once it works.
RememberDNS changes are quick to make and slow to undo. Copy your records and lower the TTL first.
Domain and hosting setups like these are part of the websites our web design team delivers.
Quick answers about DNS
What is DNS in simple terms?
The Domain Name System is the phone book of the web: it turns a name people can read, like a domain, into the numeric address of the computer that hosts the site, so the browser knows where to go.
What is an MX record?
A Mail Exchange record sends your domain’s email to the servers that host your mailboxes. A domain can have several, each with a priority, and mail goes to the next one if the first can’t take it.
What is the difference between an A record and a CNAME?
An A record points a name to the address of a server. A CNAME makes one name an alias of another, for example www pointing at your main domain, so you only keep the address in one place.
How long do DNS changes take?
Up to the record’s TTL. Google’s help gives the example of a TTL of 86,400 seconds, which can take up to 24 hours. It suggests 300 seconds before a change and 86,400 once the records are configured correctly.
Can DNS changes break my website or email?
Yes. A wrong A record sends visitors to the wrong server, and a wrong MX record sends email elsewhere. Keep a copy of your records before any change and test both right after.
Sources
Read on November 4, 2026. Google Workspace Help: DNS basics. MDN: DNS and What is a Domain Name?. Our case: our own domain’s records, read from a public resolver on November 4, 2026.