Free DNS Checker
A free DNS and TXT checker. Inspect the MX, TXT, A, AAAA and NS records that decide where a domain's mail is routed.
What this checker does
It queries the MX, TXT, A, AAAA and NS records for a domain in one pass and prints what each resolver returns. MX records come back sorted by priority, so the delivery order is immediately readable.
Queries run live over DNS-over-HTTPS against public resolvers, so what is shown is what a third party sees rather than a cached local answer.
Reading the result
MX shows where mail for the domain is delivered. For Microsoft 365 expect one record ending mail.protection.outlook.com. More than one host from different providers usually means an old configuration was never removed.
TXT carries authentication. Used as a TXT checker, this returns every TXT record on the domain at once: look for a record beginning v=spf1, alongside any provider verification strings. DKIM and DMARC live at their own names and are easier to inspect with the dedicated checkers.
NS shows which nameservers are authoritative. If these are not the provider you are editing records at, your changes are being published somewhere nothing reads.
Failures that look fine
Editing at the wrong provider. A domain registered in one place but delegated elsewhere accepts edits that never take effect. The NS records settle it.
Leftover MX records. Mail is delivered to the lowest priority host that answers. A stale record with a lower number quietly wins.
Waiting on a long TTL. A record replaced an hour ago can still be served from caches for as long as the old TTL allowed. Nothing is broken; it has not expired yet.