DNS is the directory that turns your domain name into the addresses of the machines that actually serve your website and handle your email. Those are usually separate services, and DNS is what points each part of your domain at the right one. It is invisible while correct and it takes everything down at once when it is not.
The three separate things
Most confusion comes from assuming the domain, the website, and the email are one purchase. They are three arrangements that can each sit with a different company.
- The domain is a name you lease from a registrar. It is not storage and it holds nothing.
- The website lives on a hosting server, which has its own address.
- The email is handled by a mail service, which may be the same host or a separate provider.
DNS is the layer that connects the name to the other two. Understanding that the website and the email are pointed independently explains most of what goes wrong, because it is entirely possible to move one and break the other.
The records worth knowing
| Record | What it does |
|---|---|
| A | Points the domain at the server holding the website |
| CNAME | Points one name at another name, commonly used for subdomains |
| MX | Directs email to whichever service handles your mail. Independent of the website |
| TXT | Holds verification records and mail authentication such as SPF and DMARC |
| NS | States which company's nameservers are authoritative for the domain |
That last one sits above the others. Nameservers decide who is answering the question at all, so pointing them somewhere new means all the records at the old location stop applying.
Where things break
Changing nameservers and losing everything else
The most common serious failure. Nameservers are pointed at a new host, the website works, and email stops, because the MX records existed at the old provider and were never recreated. Mail sent during that window is generally not recoverable.
Editing records at the wrong place
Records can be edited at the registrar or at the host, and only whichever holds the nameservers is actually in effect. Businesses regularly spend an afternoon changing records that are having no effect at all because the nameservers point elsewhere.
Forgetting the authentication records
SPF and DMARC live in TXT records. Moving mail without recreating them means messages start being rejected or filed as junk, and the symptom is silence rather than an error.
Two records fighting
An old record left in place alongside a new one produces intermittent behaviour, which is the hardest kind to diagnose because it works when you check it.
Why changes are not instant
Every record carries a value telling other networks how long to remember the answer before asking again. Until that time expires, networks continue serving the previous answer.
This is why a change appears to work for you and not for a colleague, and why "it has not propagated yet" is a real explanation rather than an excuse. It also explains the standard practice of lowering that value a day or two before a planned move, so the switch takes minutes rather than hours, which is set out in moving hosts without downtime.
What to know about your own setup
- Which company holds the domain, and whether the account is in your business name.
- Where the nameservers point, since that determines where records must be edited.
- Who handles your email, which is frequently not the same company as the website.
- Whether you can access all of the above, which is the question that turns a two-hour job into a two-week one when it is answered late.
Writing those four answers on one page, with who holds each login, is twenty minutes of work that saves a great deal at the worst possible moment. It is the same document recommended in what you should receive at the end of a project.
The rule worth applying
Before changing anything, export or screenshot the entire current zone. Every record, exactly as it stands.
Records are easy to change and there is frequently no history and no undo. A copy taken beforehand turns a mistake into a five-minute correction rather than an afternoon of reconstructing what used to be there while the phone is not receiving email.
Frequently asked questions
What is DNS in simple terms?
The directory that turns your domain name into the addresses of the machines serving your website and handling your email. Those are separate services, and DNS points each part of the domain at the right one.
Why did my email stop when I moved my website?
Almost certainly because nameservers were changed and the MX records existed only at the old provider. Website and email are pointed independently, so moving one without recreating the other breaks mail.
Where do I edit my DNS records?
Wherever the nameservers point, which may be the registrar or the host. Editing records at the other location has no effect at all, which catches people out regularly.
Why do DNS changes take time to appear?
Each record carries a value telling networks how long to cache the answer. Until it expires they keep serving the previous one, which is why a change can work for you and not for someone else.
What should I know about my own DNS setup?
Which company holds the domain, where the nameservers point, who handles your email, and whether you can access all three. Those four answers on one page prevent most emergencies.
What should I do before changing DNS?
Export or screenshot the entire current zone first. There is usually no history and no undo, so a copy turns a mistake into a five-minute fix rather than an afternoon of reconstruction.
West Coast Media Solutions Inc. provides web design, web development, hosting, digital marketing, and business consulting to organisations across Canada, drawing on more than twenty-five years in the field.
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