Free DNS Checker

What are DNS records?

DNS records are structured answers published by a domain’s authoritative DNS provider. When a browser, email server, certificate authority, or hosted service needs information about a domain, it asks DNS for a particular record type. The answer can point traffic to an IP address, identify a mail server, delegate authority to nameservers, or prove that a domain owner added a required verification value.

DNS is distributed and cached. That design makes it resilient, but it also means changes are not always visible everywhere at the same moment. Time to live, often called TTL, tells resolvers how long they can keep an answer before asking again.

What does this DNS checker show?

This checker queries public DNS for A, AAAA, CNAME, MX, NS, and TXT records. The result groups answers by type and shows lookup errors when a supported record type cannot be resolved. Missing records are not always failures. For example, many domains have A records but no AAAA records, or MX records only when the domain receives email.

• A and AAAA records show IPv4 and IPv6 addresses.
• CNAME records show aliases to another hostname.
• MX records show mail exchangers and their priorities.
• NS records show authoritative nameservers.
• TXT records show text values used for verification and email policy.

How to check A, AAAA, CNAME, MX, NS, and TXT records

Enter a domain, run the lookup, and review each record group. For a website, start with A, AAAA, or CNAME because those records usually determine where web traffic goes. For email, review MX and TXT records together because mail delivery often depends on both routing and sender policy. For delegation problems, compare NS records with the nameservers configured at the registrar.

If you are checking a subdomain, enter that exact hostname. Records can exist on app.example.com even when example.com has different answers. DNS is hierarchical, and the record that matters is the one clients are actually asking for.

Common DNS issues

• A or AAAA records point to an old server after a migration.
• A CNAME exists where another record type is expected, or another record exists where a CNAME must stand alone.
• MX records are missing, duplicated, or pointed at the wrong mail provider.
• NS records differ between the registrar and authoritative DNS provider.
• TXT records for SPF, DKIM, DMARC, or service verification were removed or copied incorrectly.
• DNS propagation is still in progress because resolvers are honoring cached records until TTL expires.

The best first step is to identify which record type is involved in the broken workflow. A website outage often starts with A, AAAA, or CNAME. Email delivery issues often start with MX and TXT. Certificate validation issues may involve CAA or TXT records, though this public checker focuses on the six common record types listed above.

Why DNS changes can break websites

DNS changes can break websites because they change where clients go before a web server ever receives a request. A single record can move traffic to a new IP address, remove a CDN, send users to a parked page, or disconnect a subdomain from its hosted service. If the destination does not have the right HTTPS certificate or application configuration, the site can fail even though the DNS lookup itself succeeds.

Cached DNS answers can make incidents confusing. Some users may still reach the old destination while others reach the new one. That split behavior usually resolves as TTLs expire, but it can create a noisy transition window during migrations.

How to monitor DNS changes automatically

Manual lookups are helpful when you are debugging a specific domain. Automatic monitoring is useful when DNS should stay stable and unexpected changes need attention. Website Certs can store DNS snapshots for monitored domains and alert on important changes to supported record types.

After running a public lookup, use the result CTA to start monitoring that domain. Anonymous visitors are sent to registration with the checked domain in the URL. Signed-in users are sent to the new monitor flow with the same domain prefilled.

Related website checks

DNS explains where traffic goes, but it does not prove the endpoint is healthy. Use the SSL checker to inspect certificate expiration and trust details, or use the HTTPS checker to test status codes, redirects, TLS errors, and response health. Use the Email DNS Checker for MX, SPF, DKIM, DMARC, BIMI, MTA-STS, and TLS reporting records. Use the Security Headers Checker as a related website health tool for HSTS, CSP, Referrer-Policy, and other response headers.