| 821 | Simple Mail Transfer ProtocolJ. Postel · obsoleted by RFC 2821 | Internet Standard | August 1982 |
| 822 | STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGESD. Crocker · obsoleted by RFC 2822 | Internet Standard | August 1982 |
| 1123 | Requirements for Internet Hosts - Application and SupportR. Braden, Ed. | Internet Standard | October 1989 |
| 1891 | SMTP Service Extension for Delivery Status NotificationsK. Moore · obsoleted by RFC 3461 | Proposed Standard | January 1996 |
| 1939 | Post Office Protocol - Version 3J. Myers, M. Rose | Internet Standard | May 1996 |
| 2046 | Multipurpose Internet Mail Extensions (MIME) Part Two: Media TypesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2047 | MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII TextK. Moore | Draft Standard | November 1996 |
| 2049 | Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and ExamplesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2060 | Internet Message Access Protocol - Version 4rev1M. Crispin · obsoleted by RFC 3501 | Proposed Standard | December 1996 |
| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 2305 | A Simple Mode of Facsimile Using Internet MailK. Toyoda, H. Ohno, J. Murai, D. Wing · obsoleted by RFC 3965 | Proposed Standard | March 1998 |
| 2306 | Tag Image File Format (TIFF) - F Profile for FacsimileG. Parsons, J. Rafferty | Informational | March 1998 |
| 2311 | S/MIME Version 2 Message SpecificationS. Dusse, P. Hoffman, B. Ramsdell, L. Lundblade, L. Repka | Historic | March 1998 |
| 2401 | Security Architecture for the Internet ProtocolS. Kent, R. Atkinson · obsoleted by RFC 4301 | Proposed Standard | November 1998 |
| 2440 | OpenPGP Message FormatJ. Callas, L. Donnerhacke, H. Finney, R. Thayer · obsoleted by RFC 4880 | Proposed Standard | November 1998 |
| 2487 | SMTP Service Extension for Secure SMTP over TLSP. Hoffman · obsoleted by RFC 3207 | Proposed Standard | January 1999 |
| 2821 | Simple Mail Transfer ProtocolJ. Klensin, Ed. · obsoleted by RFC 5321 | Proposed Standard | April 2001 |
| 2822 | Internet Message FormatP. Resnick, Ed. · obsoleted by RFC 5322 | Proposed Standard | April 2001 |
| 3191 | Minimal GSTN address format in Internet MailC. Allocchio | Draft Standard | October 2001 |
| 3192 | Minimal FAX address format in Internet MailC. Allocchio | Draft Standard | October 2001 |
| 3207 | SMTP Service Extension for Secure SMTP over Transport Layer SecurityP. Hoffman | Proposed Standard | February 2002 |
| 3302 | Tag Image File Format (TIFF) - image/tiff MIME Sub-type RegistrationG. Parsons, J. Rafferty | Draft Standard | September 2002 |
| 3464 | An Extensible Message Format for Delivery Status NotificationsK. Moore, G. Vaudreuil | Draft Standard | January 2003 |
| 3949 | File Format for Internet FaxR. Buckley, D. Venable, L. McIntyre, G. Parsons, J. Rafferty | Draft Standard | February 2005 |