Free tool
Email security check
See how well a domain is protected against spoofing and phishing: SPF, DMARC, DKIM and MTA-STS, checked from public DNS in seconds. No sign-up.
What is checked
SPF
Lists the servers allowed to send mail for the domain.
DMARC
Tells receivers what to do with mail that fails the checks: the setting that actually stops spoofing.
DKIM
Signs outgoing mail so it can be proven genuine and unaltered.
MTA-STS
Makes other mail servers use an encrypted connection when delivering to you.