You’ve bought a domain, or you’re moving your website to a new host, and somebody tells you to “just update the DNS”. Then you log in to your domain account and find a table full of letters: A, CNAME, MX, TXT, NS. Change the wrong one and your website disappears, or worse, your email stops arriving.
DNS isn’t as scary as it looks. Most small business domains only use a handful of record types, and each one has a single, simple job. This guide explains what each record does, how to point your domain at a new host safely, and the mistakes I see most often when I’m asked to sort out a domain that’s stopped working.
What DNS actually does
DNS (the Domain Name System) is the internet’s address book. People remember names like yourbusiness.co.uk, but computers connect to numbered IP addresses. When someone types your domain into a browser, or sends you an email, their device asks DNS where to go, and DNS answers using the records you’ve set.
Those records live with whoever runs your domain’s nameservers. That might be the company you registered the domain with, your web host, or a service like Cloudflare. Knowing which one it is matters, because that’s the only place your changes will have any effect.
NS records: who is in charge
NS (nameserver) records say which DNS service holds the records for your domain. You normally set them at your domain registrar, not inside the DNS table itself. They look something like this:
ns1.examplehost.co.uk
ns2.examplehost.co.ukIf you edit records with one company while your nameservers point to another, nothing will change. That’s the single most common reason I hear “I updated the DNS and nothing happened”. Check your nameservers first.
A and AAAA records: where your website lives
An A record points a name at an IPv4 address, the familiar four-number format like 203.0.113.10. An AAAA record does the same job for the longer IPv6 addresses. When you move to a new web host, they’ll give you the IP address of your new server, and the A record for your domain is usually what you change.
You’ll often see two entries: one for the bare domain (shown as @ or left blank) and one for www. Both need to lead to the same place, either with two A records or with www set up as a CNAME, which comes next.
CNAME records: an alias for another name
A CNAME says “this name is really that other name”. Instead of pointing at an IP address, it points at another hostname. It’s handy for www, and for services like website builders, booking systems or email platforms that ask you to point a subdomain at them.
One rule catches people out: under the DNS standards you can’t put a CNAME on the bare domain itself, and a name with a CNAME can’t have any other records. Some DNS providers offer workarounds (often called CNAME flattening or ALIAS records), but if yours doesn’t, use an A record for the bare domain.
MX records: where your email goes
MX (mail exchange) records tell the world which servers accept email for your domain. Each one has a priority number, and lower numbers are tried first. If you use Microsoft 365, Google Workspace or your host’s mailboxes, your provider will tell you exactly which MX records to add.
This is the record to be most careful with. Your website and your email don’t have to live in the same place, and often they don’t. If you move your site to a new host but your email stays with Microsoft 365, your MX records must stay exactly as they are.
TXT records: proof and permissions
TXT records hold short pieces of text that other services read. They’re used to prove you own a domain (Google, Microsoft and many other tools ask for one) and for the email authentication records SPF, DKIM and DMARC. If your emails are landing in junk, I’ve covered those in detail in Why are my emails going to spam?
A domain can have several TXT records, but it should only ever have one SPF record. Two SPF records is a common mistake, and it can make both of them fail.
TTL and propagation: why changes take time
Every record has a TTL (time to live), measured in seconds. It tells other servers how long they may remember the answer before asking again. A TTL of 3600 means an hour, and 86400 means a whole day.
That caching is why DNS changes aren’t instant. Until the old cached answer expires, some visitors will still reach your old server while others see the new one. Changing nameservers can take longer again, so hosts often quote up to 24 to 48 hours, although many changes show up much faster than that.
How to point your domain at a new host safely
Here’s the order I follow when I move a client’s website, which keeps downtime and lost email to a minimum:
- Write down your current records. Take a screenshot or export of every record before you touch anything, especially MX, TXT and any CNAMEs set up by other services.
- Lower the TTL a day ahead. Dropping the TTL on the records you’ll change to something short, such as 300 seconds (five minutes), means the switch takes effect quickly once you make it.
- Set up the site on the new host first. Copy the website across and check it works before you send any visitors to it.
- Change only what you need to. For most moves that’s the A record for the bare domain and
www. Leave the MX and TXT records alone unless your email is moving too. - Sort out SSL. Once the domain points at the new server, make sure an SSL certificate is issued so the site loads on
https://without warnings. - Keep the old hosting for a few days. Don’t cancel it until you’re sure everything, including email, is working from the new setup.
If you’re changing nameservers rather than single records, the new DNS provider starts with its own table. Recreate every record from your notes there before you switch the nameservers over, or your email can stop the moment the change goes live.
How to check your DNS records
You don’t need special software. Free tools such as Google Admin Toolbox Dig let you look up any record type for your domain. On a Mac or Linux computer, the dig command does the same from the terminal, and on Windows you can use nslookup:
dig yourbusiness.co.uk A
dig yourbusiness.co.uk MX
nslookup -type=mx yourbusiness.co.ukIf your host uses cPanel or Plesk, both have a DNS editor built in, but they only matter if your nameservers point to that server. My cPanel vs Plesk comparison explains where to find things in each.
Common DNS mistakes to avoid
- Editing DNS in the wrong place. Always check which nameservers your domain uses before making changes.
- Deleting MX records during a website move. The site comes back, but email quietly stops arriving.
- Forgetting the www version. The bare domain works but
www.yourbusiness.co.ukdoesn’t, or the other way round. - Two SPF records. Merge them into one record instead.
- Letting the domain expire. Every record stops working when the registration lapses, so keep auto-renew switched on and your contact email up to date.
Need help?
I set up domains, DNS, hosting and business email for small businesses in Milton Keynes and across the UK. If you’re moving host, your site has vanished after a DNS change, or you’d just like someone to check things over, get in touch and I’ll take a look.
