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FreeMailCheck Tools SMTP TLS Certificate Checker " data-section="" data-keywords="certificate,issuer,subject,valid,tls,cipher" >
FREE EMAIL INFRASTRUCTURE TOOL

SMTP TLS Certificate Checker

Inspect SMTP STARTTLS certificate and TLS metadata when the remote server and scanner network allow a handshake.

What this tool checks

Inspect SMTP STARTTLS certificate and TLS metadata when the remote server and scanner network allow a handshake.

FreeMailCheck reports only evidence it can observe. Network-dependent or message-level evidence can remain unknown when it cannot be verified reliably.

How to use this tool

  1. Enter the requested domain, hostname, IP address or email-header data.
  2. Run the check and wait for FreeMailCheck to collect the available DNS, SMTP or message evidence.
  3. Review the result details and warnings before changing a production mail configuration.

Understanding the results

This tool reports evidence that can be observed at the time of the check. DNS propagation, remote SMTP policies, network restrictions and unavailable message-level evidence can affect results.

An unknown result is not automatically a failure. FreeMailCheck avoids treating unavailable evidence as proof of an email configuration problem.

Related FreeMailCheck tools

SMTP Checker → STARTTLS Checker → SMTP TLS Cipher Checker → MTA-STS Checker → TLS-RPT Checker →