SMTP DSN # Server-side # Special Replies, so the server does not have to understand DSN REPLY MAIL 250 Ok REPLY RCPT 250 Ok # Client-side smtp SMTP DSN From: different To: another body smtp://%HOSTIP:%SMTPPORT/%TESTNUMBER --mail-rcpt "%LTrecipient@example.com%GT NOTIFY=SUCCESS,FAILURE" --mail-from "%LTsender@example.com%GT RET=HDRS" -T - # Verify data after the test has been "shot" EHLO %TESTNUMBER MAIL FROM:%LTsender@example.com%GT RET=HDRS RCPT TO:%LTrecipient@example.com%GT NOTIFY=SUCCESS,FAILURE DATA QUIT From: different To: another body .