F FreeMailCheck
☕ Support
FreeMailCheck Tools DKIM Key Length Checker " data-section="" data-keywords="key_bits,key_type,public_key,selector" >
FREE EMAIL INFRASTRUCTURE TOOL

DKIM Key Length Checker

Check an explicit DKIM selector and inspect RSA or Ed25519 key details, including detected key strength where available.

What this tool checks

Check an explicit DKIM selector and inspect RSA or Ed25519 key details, including detected key strength where available.

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

DKIM Checker → DKIM Selector Checker → DKIM Record Parser → DKIM Revocation Checker → DKIM Generator →