Following the Mailman: Tracking Your Email's Route

When a script or cron job sends mail and you need to confirm what actually happened on the wire, the mail utility has a built-in verbose flag that dumps the full SMTP conversation to stderr.

Usage

mail -v <recipient>

Replace <recipient> with the target address. Once you press Enter, the utility prompts for the message body. After you close the message (typically with Ctrl+D), the verbose output shows the complete SMTP handshake, including:

• The EHLO / HELO greeting and server response
• MAIL FROM and RCPT TO exchanges
• The DATA block with the message headers and body
• The final QUIT and server confirmation

Why It Helps

Most mail delivery failures are silent. The command exits with code 0, the script moves on, and the message simply never arrives. Running with -v lets you see exactly where the transaction breaks: a rejected recipient, a TLS negotiation failure, or a relay that drops the message after accepting it.

Tips

• Combine with 2>&1 | tee /tmp/mail-debug.log to capture the output for later review.
• If your system uses mailx or s-nail instead of the classic mail, the -v flag works the same way.
• For sendmail directly, the equivalent is sendmail -v <recipient>.

• SysAdmin

• Bash
• Troubleshooting