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FreeMailCheck Tools SMTP TLS Cipher Checker " data-section="" data-keywords="cipher,tls,starttls,crypto" >
FREE EMAIL INFRASTRUCTURE TOOL

SMTP TLS Cipher Checker

Probe an SMTP hostname and inspect the TLS cipher observed after STARTTLS where the network permits it.

What this tool checks

Probe an SMTP hostname and inspect the TLS cipher observed after STARTTLS where the network permits it.

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 → TLS Certificate Checker → MTA-STS Checker → TLS-RPT Checker →