SMTP SASL SASL AUTH PLAIN RFC4616 RFC4954 # # Server-side AUTH PLAIN REPLY AUTH 334 PLAIN supported REPLY AHVzZXIAc2VjcmV0 235 Authenticated # # Client-side smtp SMTP plain authentication mail body smtp://%HOSTIP:%SMTPPORT/%TESTNUMBER --mail-rcpt recipient@example.com --mail-from sender@example.com -u user:secret -T - # # Verify data after the test has been "shot" EHLO %TESTNUMBER AUTH PLAIN AHVzZXIAc2VjcmV0 MAIL FROM: RCPT TO: DATA QUIT mail body .