Inbound routing
MX records identify the servers designated to receive mail for the domain.
Free email DNS tool
Check the DNS behind business email.
Inspect MX routing, SPF, DMARC, an optional DKIM selector, CAA and DNSSEC-related resolver state before an email migration or deliverability investigation.
Results
Email DNS
What each check means
Authentication records have different jobs.
Sending authorization
SPF is normally published as a TXT record beginning with v=spf1. Multiple independent SPF records can create policy problems.
Alignment + policy
DMARC is published below _dmarc and describes alignment/policy/reporting behavior.
Message signatures
DKIM public keys are selector-specific. The tool checks the selector you provide rather than guessing one.
Certificate-authority policy
CAA is not an email-authentication record, but it is useful infrastructure context for the same domain.
DNS validation context
The resolver AD flag indicates that the recursive resolver authenticated the DNS response. It does not make email content trustworthy.
Changing mail providers?
Inventory DNS before the cutover.
Record current MX, SPF, DKIM, DMARC and verification records before changing nameservers or mail routing.