When a visitor types your domain, something faster than a blink happens: the name becomes an IP address through the Domain Name System. If one record is wrong, the site will not load or email will not arrive, and it will look like a hosting failure when the cause is a single line in your DNS panel.
What DNS really is
Imagine a giant phone book spread across the internet: the name on the left, the number on the right. DNS servers are that book, and records are the lines. Your browser asks a resolver for the number, then connects to the server that holds your files.
The records you will actually meet
| Record | What it does | When to change it |
|---|---|---|
| A | Points to an IPv4 address | Changing hosts |
| AAAA | Points to IPv6 | Supporting modern networks |
| CNAME | Alias to another name | www or third-party services |
| MX | Mail receiving servers | Changing email provider |
| TXT | Verification and policy text | Ownership and SPF |
| NS | Authoritative name servers | Moving DNS to a new host |
| SOA | Zone administration data | Rarely |
Check your records now
You do not need a terminal. Use the free DNS lookup tool, enter your domain without www, and read the table with TTL values. The first rule of diagnosis: never fix what you have not measured.
Common mistakes that break sites
- A typo in the A record: only some visitors see the site, others land on a stranger's server.
- No www record: the root domain works, www shows a not-found page.
- Deleting MX records: email seems broken while messages are routed to a dead host.
- Impatience after editing: propagation takes minutes to hours depending on TTL, and repeated edits multiply the confusion.
When you must edit records
Three cases cover most work: moving hosting (A and CNAME), changing email (MX and TXT), and verifying a third-party service (TXT). If your job is connecting a domain to hosting for the first time, follow connecting a domain with name servers.
What TTL really does
TTL is how many seconds a record may stay cached by resolvers. A record with 3600 may take an hour to change for everyone; 300 takes five minutes. Before a big migration, lower the TTL to 300 a day ahead, make the change, then raise it again. Many edits that «did not work» were correct and simply had not propagated yet.
DNS or hosting? How to tell in four checks
- Inspect the A record: a wrong IP means the problem is DNS.
- Open the site by IP address; if it loads, name resolution is the fault.
- Test from another network or a phone; different results mean caching.
- Read the SOA record to confirm which server owns the zone.
These four checks save hours of support messages, and the lookup tool shows all of them without an account.
A useful habit
- Check your current records and save a copy before any change.
- Compare the A record with the IP your host gave you.
- Confirm www exists, and mail records if you use email on the domain.
- If HTTPS fails after the change, read common SSL errors.
DNS is not an engineer-only detail. It is the first thing you need when something breaks, and the first thing that saves you a support ticket and a long wait.
Three real cases
Case one: moving hosts; update both the A record and www, and lower TTL a day earlier. Case two: mail stops; check MX first, then SPF in TXT. Case three: SSL fails after connecting; usually a missing CNAME or a stale A record pointing to the old server. Keep a short dated note of every change and the next incident becomes minutes, not hours.
A checklist before any edit
Before touching a record: save the current values, confirm the IP with your host, and know how long propagation will take at that TTL. After the edit, check from another device or an external tool so your own cache does not mislead you.