MX lookup & SMTP test
See which servers receive mail for a domain — and test each one live: SMTP banner, STARTTLS and certificate.
5 free checks per day · then from $0.04 per check — pricing
What the MX Lookup & SMTP Test checks
- MX records, null MX, CNAME targets
- IPv4/IPv6 addresses and reverse DNS
- Live SMTP banner and EHLO
- STARTTLS, TLS version and cipher
- Certificate trust, expiry and hostname
- MTA-STS, TLS-RPT and DANE
How it works
- 1
Enter a domain
- 2
We resolve the MX hosts and connect to them
- 3
Fix delivery and TLS problems
Frequently asked questions
Does the SMTP test send an email?
No. We connect, read the banner, send EHLO and STARTTLS, check the certificate and quit. No MAIL or RCPT command is sent.
What is MTA-STS?
A standard (RFC 8461) that tells sending servers to require a valid TLS connection to your MX hosts, preventing downgrade and interception attacks.