What the DNS checker shows
DNS tells browsers where your website lives and tells mail servers where to deliver your email. Enter a domain or subdomain, such as example.com or shop.example.com, and the checker lists its current public records in one place: A, AAAA, CNAME, MX, TXT and NS, plus the SOA record, with the time of the check.
For a root domain, the CNAME row also looks at the www. version, because that's where a CNAME usually lives (for example www.example.com → example.com).
The results are what our resolver sees at that moment. It isn't a worldwide propagation map: if you've just changed a record, some networks may still be serving the old answer for a while. You get 5 free checks without an account, shared across all the UpMonix tools, and 5 more with your email address.
Record types explained
| Record | What it does | What "wrong" looks like |
|---|---|---|
| A | Points a name to an IPv4 address (your web server) | An old server's address after a move, or an address you don't recognise |
| AAAA | The same, for an IPv6 address | An IPv6 address for a server that no longer answers on it; visitors on IPv6 get errors |
| CNAME | Makes one name an alias of another name | An alias to a service you've stopped using |
| MX | Says which servers accept email for the domain | Your old email provider still listed (see the MX checker) |
| TXT | Free text used for verification and email security (SPF, for example) | No SPF record, two SPF records, or verification strings you can't explain |
| NS | Names the nameservers in charge of the domain's DNS | Nameservers you didn't choose |
| SOA | Technical details of the zone: primary nameserver, serial number, timers | A serial number that changed when nobody made a change |
Common DNS problems and how to fix them
Site moved, but the A record still points to the old server
You've moved host, but visitors still land on the old server, or on an error once it's switched off. Compare the A (and AAAA) record with the address your new host gave you and update it where your DNS is managed. That's the provider named in the NS row, which isn't always your registrar.
CNAME at the root
DNS rules don't let a name that has a CNAME hold any other records (RFC 1034, section 3.6.2). The root of your domain always has NS and SOA records, so a CNAME there breaks things, often email first. Put the CNAME on www and use an A record at the root, or use your DNS provider's alias feature if it offers one (it may be called ALIAS, ANAME or CNAME flattening).
Missing SPF or DMARC records
SPF is a TXT record at the root that starts v=spf1 and lists who may send email for your domain. Without it, your messages are more likely to be marked as spam or rejected. The checker shows it in the TXT row. DMARC lives at a separate name, _dmarc.example.com. Enter that name in the checker to see your DMARC record in the TXT row. DKIM keys live at <selector>._domainkey.yourdomain. Your selector is in your email provider's settings (for example google, or selector1 and selector2), or in the s= tag of the DKIM-Signature header on an email you've received from your domain.
Nameservers changed unexpectedly
The NS records decide who controls all your other records. If they change without your say-so, whether through a registrar mistake or a compromised account, your website and email can be pointed anywhere. Log in to your registrar, change your password, turn on two-factor authentication and set the nameservers back. Our guide to DNS hijacking covers the warning signs.
When a one-off check isn't enough
DNS problems are quiet: nothing on your site tells you a record changed overnight. UpMonix records your known-good DNS and nameserver settings and emails you when something important changes, so you can put it right before traffic or email goes astray.
DNS and nameserver monitoring are included on every plan. The Free plan is free forever for one domain, with no credit card needed, and adds uptime, SSL, domain expiry and MX checks. Paid plans add more monitors, faster checks and more alert channels: see pricing.
FAQ
How long do DNS changes take?
It depends on the record's TTL (time to live), which tells resolvers how long they may cache the old answer. A change is live at your DNS provider straight away, but a network that cached the old record can keep using it until the TTL runs out. Lowering the TTL a day before a planned change helps it take effect faster.
What's the difference between A and CNAME?
An A record points a name straight at an IPv4 address, such as your web server. A CNAME points a name at another name, and the visitor's resolver then looks that name up. CNAMEs suit services that manage their own addresses, such as a shop platform. You can't use a CNAME at the root of your domain.
Can I check TXT records for email verification?
Yes, for records on the name you enter. The TXT row shows everything published there, including SPF and most verification strings from Google, Microsoft and similar services. For DMARC or DKIM, enter the full name, such as _dmarc.example.com or selector._domainkey.example.com, and the checker shows the TXT record published there. If your DKIM record is a CNAME, as some providers such as Microsoft 365 publish it, the checker shows the CNAME and no TXT record; look up the CNAME target to see the key.
Will UpMonix alert me if my DNS changes?
Yes. DNS monitoring and nameserver monitoring are included on every UpMonix plan, including Free, which is free forever for one domain. UpMonix compares your records with a known-good baseline and emails you when important records such as A, AAAA or CNAME change, or when your nameservers do.
Is this tool free?
Yes. You can run 5 checks without an account, shared across all the UpMonix tools, and add your email address to unlock 5 more. Cookies must be enabled. If you'd like your DNS watched continuously, create a free UpMonix account for one domain.