MX record lookup
List a domain's mail exchangers and priorities, confirm each resolves to a reachable address, and catch the misconfigurations that break inbound mail.
What this catches
Every problem below is one this tool detects and explains, with the record to publish.
An MX host does not resolve to an address
A mail exchanger is published but its hostname has no A or AAAA record.
An MX host resolves to a private address
A published mail exchanger points into private address space and is unreachable from the internet.
An MX record points at an alias
MX targets must be hostnames with address records, not CNAMEs.
Domain declares that it does not accept mail
A null MX record is published, which is the correct way to say so.
No MX records found
This domain publishes no mail exchangers, so it cannot receive email.
Only one mail exchanger is published
There is no backup path if this host becomes unreachable.
Related tools
- Full domain health checkCheck SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT and BIMI for any domain in one pass, with the exact records and the fix for anything that is wrong.
- SPF checkerLook up a domain's SPF record, validate its syntax, and count the DNS lookups it costs — including every nested include — against the limit of ten.
- DMARC checkerLook up and validate a domain's DMARC record, read back what its policy actually does, and see what is needed to move to enforcement.
- DKIM checkerCheck a DKIM selector for a domain, validate the record, and read the key strength. Leave the selector blank to probe the selectors common providers use.