SMTP SASL SASL AUTH DIGEST-MD5 SASL AUTH PLAIN SASL DOWNGRADE RFC2831 RFC4954 # # Server-side AUTH DIGEST-MD5 PLAIN REPLY "AUTH DIGEST-MD5" 334 Rubbish REPLY * 501 AUTH exchange cancelled by client REPLY "AUTH PLAIN" 334 PLAIN supported REPLY AHVzZXIAc2VjcmV0 235 Authenticated # # Client-side smtp !SSPI debug crypto SMTP DIGEST-MD5 authentication with SASL downgrade 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 DIGEST-MD5 * AUTH PLAIN AHVzZXIAc2VjcmV0 MAIL FROM: RCPT TO: DATA QUIT mail body .