SMTP SASL SASL AUTH LOGIN SASL-IR RFC4954 # # Server-side AUTH LOGIN REPLY AUTH 334 UGFzc3dvcmQ6 REPLY c2VjcmV0 235 Authenticated # # Client-side smtp SMTP login authentication with initial response mail body smtp://%HOSTIP:%SMTPPORT/%TESTNUMBER --mail-rcpt recipient@example.com --mail-from sender@example.com -u user:secret --sasl-ir -T - # # Verify data after the test has been "shot" EHLO %TESTNUMBER AUTH LOGIN dXNlcg== c2VjcmV0 MAIL FROM: RCPT TO: DATA QUIT mail body .