SMTP SMTP AUTH PLAIN SASL-IR RFC4616 RFC4954 # # Server-side REPLY EHLO 250 AUTH PLAIN REPLY AUTH 235 Authenticated # # Client-side smtp SMTP plain authentication with initial response mail body smtp://%HOSTIP:%SMTPPORT/user --mail-rcpt 907@foo --mail-from 907@from -u test:1234 --sasl-ir -T - # # Verify data after the test has been "shot" EHLO user AUTH PLAIN dGVzdAB0ZXN0ADEyMzQ= MAIL FROM:<907@from> RCPT TO:<907@foo> DATA QUIT mail body .