DNS is often described as the internet’s address book. Each domain has a small set of records — individual entries that tell the world where your website lives, where to deliver your email, and who is allowed to issue SSL certificates for you.
You don’t need to memorise them, but knowing what each one does makes migrations, email setups and troubleshooting far less stressful. Here is every record type a small business is likely to meet.
The Records at a Glance
| Record | What it does | Typical example |
|---|---|---|
| A | Points a name to an IPv4 address | example.co.uk → 203.0.113.10 |
| AAAA | Points a name to an IPv6 address | example.co.uk → 2001:db8::10 |
| CNAME | Makes one name an alias of another name | www → example.co.uk |
| MX | Says which servers receive your email | 10 mail.example.co.uk |
| TXT | Free text — used for SPF, DKIM, DMARC and verification | v=spf1 include:... ~all |
| NS | Names the servers that hold your DNS | ns1.yourhost.com |
| CAA | Limits which authorities can issue SSL certificates | 0 issue "letsencrypt.org" |
| SOA | Admin details for the zone, including a serial number | Managed by your DNS host |
A and AAAA Records — Where Your Website Lives
An A record connects a name (like example.co.uk or shop.example.co.uk) to the IPv4 address of the server that hosts it. An AAAA record does the same for IPv6. When you move hosting, these are usually the records that change.
Common mistake: updating the A record for example.co.uk but forgetting www — so one address shows the new site and the other shows the old one.
CNAME Records — Aliases
A CNAME says “this name is the same as that name”. It is handy for subdomains that should follow another address automatically — for example pointing www at your main domain, or a subdomain at a third-party service.
Rules worth knowing: a name that has a CNAME cannot have any other records, and you can’t put a CNAME on the bare domain itself (example.co.uk) because it must also hold NS and SOA records. Use an A record there instead.
MX Records — Where Your Email Goes
MX records tell other mail servers where to deliver email for your domain. Each one has a priority number: lower numbers are tried first, higher numbers act as backups.
Common mistake: moving your website and accidentally deleting or changing the MX records — email quietly stops arriving. Always note your MX records before a migration. (If you don’t have a business email on your domain yet, here’s why it’s worth having.)
TXT Records — Proof and Protection
TXT records hold text that other services read. The important ones for email are:
- SPF — lists the servers allowed to send email for your domain.
- DKIM — publishes a key that receiving servers use to verify your messages haven’t been tampered with.
- DMARC — tells receivers what to do with messages that fail SPF or DKIM, and where to send reports.
Together they help your email reach inboxes and make your domain much harder to spoof. TXT records are also used to verify domain ownership for services like Google Search Console.
Common mistake: having two separate SPF records. There must be only one — combine the entries into a single record. Our free email checker spots this and other SPF, DKIM and DMARC problems; for the full picture read SPF, DKIM and DMARC explained.
NS Records — Who Runs Your DNS
NS (nameserver) records say which company’s servers hold all your other records. Changing nameservers moves your entire DNS to a new provider in one go — so the new provider must already have your records set up. Read how to change nameservers safely.
CAA Records — SSL Guardrails
A CAA record lists which certificate authorities may issue SSL certificates for your domain. It is optional, but it stops a certificate being issued by an authority you never use. If you add one, make sure it includes every authority you rely on — or certificate renewals can fail.
SOA — The Zone’s Paperwork
The SOA (Start of Authority) record holds administrative details, including a serial number that increases when the zone changes. Your DNS host manages it for you.
TTL — The Setting on Every Record
Every record carries a TTL (time to live) that tells resolvers how long they may cache it. It is the single biggest factor in how quickly changes appear — see what TTL is and what to set it to.
Check Any Record in Seconds
Our free DNS checker looks up A, AAAA, CNAME, MX, NS, TXT and CAA records straight from your nameservers and from major public resolvers, so you can see exactly what the world sees.
Frequently Asked Questions
Should www be an A record or a CNAME?
Either works. A CNAME to your main domain means you only update one A record when you move hosting; an A record gives you independent control.
Do I need AAAA records?
Only if your server has an IPv6 address. If it doesn’t, leave AAAA out rather than pointing it somewhere wrong.
I added a record but it isn’t working yet.
New records usually appear within minutes, but resolvers may have cached a “doesn’t exist” answer. Check it with the DNS checker and read how propagation works.
