DNS explained: the records behind your domain, and why one typo takes you offline
A handful of text entries decide whether your website loads and your email arrives. Here's what each one does — and which mistakes take a business down for a day.
You own a domain. It cost about ten dollars. And somewhere behind it sits a short list of text entries that decide whether your website loads, whether your email arrives, and whether a customer searching for you finds anything at all.
Most business owners never see that list. That's usually fine — right up until something breaks, and every explanation online assumes you already know what an A record is.
This is what's actually in there.
What DNS is
Computers talk in numbers: 103.89.13.175. People remember names: yourbusiness.com. DNS is the phone book that translates between the two.
When someone types your domain, their browser asks the DNS system "where does this live?", gets an address back, and goes there. The whole exchange takes milliseconds and nobody notices — until an entry is wrong, and then nothing works and there's no error message explaining why.
The records that matter
A — where the website lives
Points your domain at a server's IP address.
yourbusiness.com A 103.89.13.175
That's it. Change this and your site moves. Get it wrong and visitors see nothing, a stranger's site, or a browser error.
CNAME — an alias for another name
Says "this name is really that other name".
www.yourbusiness.com CNAME yourbusiness.com
⚠️ Which is why www.yourbusiness.com sometimes works and yourbusiness.com doesn't, or the reverse. They're two separate entries, and plenty of sites only ever configured one.
MX — where the email goes
Mail eXchange: which servers receive email for your domain.
yourbusiness.com MX 10 mx.zoho.com
⛔ This is the one that causes silent disasters. MX records are completely independent of your website. Move your site to a new host, let them "set up your DNS", and if they don't copy the MX records across, your website works perfectly while your email quietly stops arriving. Customers write to you. Nothing bounces. You find out days later.
TXT — notes that machines read
Free-form text used for verification and email authentication. This is where SPF, DKIM and DMARC live — the three records that decide whether your email reaches the inbox or spam. We wrote about those separately.
NS — who is in charge
Which servers hold the authoritative answers for your domain. Change these and you've moved your entire DNS management somewhere else.
The mistakes that actually take businesses offline
Migrating a site and forgetting the MX records. The most expensive one, because it fails silently. The website looks perfect. The email is gone.
Two SPF records. A domain may have exactly one. Add a second when you change email providers and neither is valid — everything starts landing in spam, weeks after a change nobody connects it to.
Waiting on propagation that already happened. DNS answers are cached for a set time (the TTL). Change a record with a 24-hour TTL and some of the internet keeps using the old answer for a day. ⭐ Drop the TTL to five minutes before a planned migration and the switch is nearly instant.
Letting someone else own your domain. If your agency registered it in their account, you don't control your own DNS — and getting it back is a negotiation, not a setting. ⛔ The domain should always be registered in your name, on your account. Always.
A registrar's cheap first year. Some sell a .com for a few dollars and renew it at several times that. It isn't a scam, it's the business model — but it's worth knowing before you commit.
What we actually do about it
None of this is difficult. It's just unforgiving: one wrong character and something stops working, usually without telling you.
So when we set up hosting, DNS is our job:
- Point the domain, correctly, and check the MX records survive the move before we touch anything
- Configure SSL so it issues and renews on its own
- Set up email authentication and confirm it passes
- Lower the TTL before a migration, so the switch is minutes rather than a day
- Keep the domain registered in your name, on your account — we ask for access, not ownership, and you can remove it whenever you like
⭐ You never open a DNS panel. That's the point of paying someone: not that it's hard, but that it's the sort of thing that quietly ruins a Tuesday.