SMTP SMTP AUTH LOGIN SASL-IR RFC4954 # # Server-side AUTH LOGIN REPLY AUTH 334 UGFzc3dvcmQ6 REPLY MTIzNA== 235 Authenticated # # Client-side smtp SMTP login authentication with initial response mail body smtp://%HOSTIP:%SMTPPORT/920 --mail-rcpt recipient@example.com --mail-from sender@example.com -u test:1234 --sasl-ir -T - # # Verify data after the test has been "shot" EHLO 920 AUTH LOGIN dGVzdA== MTIzNA== MAIL FROM: RCPT TO: DATA QUIT mail body .