SMTP Test Tool StruisICT
Use this command to install SMTP Test Tool:
winget install --id=StruisICT.SmtpTestTool -e smtp-test-tool is a single static binary that lets IT teams verify SMTP / IMAP / POP3 connectivity, exercise STARTTLS / SSL / AUTH paths, and translate cryptic 5.7.x bounce codes into IT-actionable remediation steps. Ships with a CLI and a native GUI in one download; runs entirely on rustls (no OpenSSL); stores credentials in the Windows Credential Manager.