RFC 1731 

Proposed Standard 

John G. Myers, IMAP4 Authentication Mechanisms, December 1994.

RFC 2195 

Proposed Standard 

J. Klensin, R. Catoe, P. Krumviede, IMAP/POP AUTHorize Extension for Simple Challenge/Response, September 1997.

RFC 2222 

Proposed Standard 

John G. Myers, Simple Authentication and Security Layer (SASL), October 1997.

RFC 2246 

Proposed Standard 

T. Dierks, C. Allen, The TLS Protocol Version 1.0, January 1999.

RFC 2505BCP 30 

Best Current Practice 

G. Lindberg, Anti-Spam Recommendations for SMTP MTAs, February 1999.

RFC 2554 

Proposed Standard 

John G. Myers, SMTP Service Extension for Authentication, March 1999.

RFC 2595 

Proposed Standard 

C. Newman, Using TLS with IMAP, POP3, and ACAP, June 1999. (Supported by MMP, POP and IMAP.)

RFC 2831 

Proposed Standard 

P. Leach, C. Newman, Using Digest Authentication as a SASL Mechanism, May 2000. (Not yet supported by MMP.)

RFC 3207 

Proposed Standard 

P. Hoffman, SMTP Service Extension for Secure SMTP over Transport Layer Security, February 2002.