| 733 | Standard for the format of ARPA network text messagesD. Crocker, J. Vittal, K.T. Pogran, D.A. Henderson · obsoleted by RFC 822 | Unknown | November 1977 |
| 791 | Internet ProtocolJ. Postel | Internet Standard | September 1981 |
| 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 |
| 1034 | Domain names - concepts and facilitiesP. Mockapetris | Internet Standard | November 1987 |
| 1035 | Domain names - implementation and specificationP. Mockapetris | Internet Standard | November 1987 |
| 1506 | A Tutorial on Gatewaying between X.400 and Internet MailJ. Houttuin | Informational | August 1993 |
| 1652 | SMTP Service Extension for 8bit-MIMEtransportJ. Klensin, N. Freed, M. Rose, E. Stefferud, D. Crocker · obsoleted by RFC 6152 | Draft Standard | July 1994 |
| 1733 | Distributed Electronic Mail Models in IMAP4M. Crispin | Informational | December 1994 |
| 1767 | MIME Encapsulation of EDI ObjectsD. Crocker | Proposed Standard | March 1995 |
| 1939 | Post Office Protocol - Version 3J. Myers, M. Rose | Internet Standard | May 1996 |
| 1985 | SMTP Service Extension for Remote Message Queue StartingJ. De Winter | Proposed Standard | August 1996 |
| 2033 | Local Mail Transfer ProtocolJ. Myers | Informational | October 1996 |
| 2045 | Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message BodiesN. Freed, N. Borenstein | Draft Standard | November 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 |
| 2142 | Mailbox Names for Common Services, Roles and FunctionsD. Crocker | Proposed Standard | May 1997 |
| 2181 | Clarifications to the DNS SpecificationR. Elz, R. Bush | Proposed Standard | July 1997 |
| 2369 | The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header FieldsG. Neufeld, J. Baer | Proposed Standard | July 1998 |
| 2442 | The Batch SMTP Media TypeN. Freed, D. Newman, J. Belissent, M. Hoy | Informational | November 1998 |
| 2480 | Gateways and MIME Security MultipartsN. Freed | Proposed Standard | January 1999 |
| 2505 | Anti-Spam Recommendations for SMTP MTAsG. Lindberg | Best Current Practice | February 1999 |
| 2645 | ON-DEMAND MAIL RELAY (ODMR) SMTP with Dynamic IP AddressesR. Gellens | Proposed Standard | August 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 |
| 2919 | List-Id: A Structured Field and Namespace for the Identification of Mailing ListsR. Chandhok, G. Wenger | Proposed Standard | March 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 |
| 3297 | Content Negotiation for Messaging Services based on EmailG. Klyne, R. Iwazaki, D. Crocker | Proposed Standard | July 2002 |
| 3458 | Message Context for Internet MailE. Burger, E. Candell, C. Eliot, G. Klyne | Proposed Standard | January 2003 |
| 3461 | Simple Mail Transfer Protocol (SMTP) Service Extension for Delivery Status Notifications (DSNs)K. Moore | Draft Standard | January 2003 |
| 3462 | The Multipart/Report Content Type for the Reporting of Mail System Administrative MessagesG. Vaudreuil · obsoleted by RFC 6522 | Draft Standard | January 2003 |
| 3463 | Enhanced Mail System Status CodesG. Vaudreuil | Draft Standard | January 2003 |
| 3464 | An Extensible Message Format for Delivery Status NotificationsK. Moore, G. Vaudreuil | Draft Standard | January 2003 |
| 3501 | INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1M. Crispin · obsoleted by RFC 9051 | Proposed Standard | March 2003 |
| 3798 | Message Disposition NotificationT. Hansen, Ed., G. Vaudreuil, Ed. · obsoleted by RFC 8098 | Draft Standard | May 2004 |
| 3801 | Voice Profile for Internet Mail - version 2 (VPIMv2)G. Vaudreuil, G. Parsons | Draft Standard | June 2004 |
| 3834 | Recommendations for Automatic Responses to Electronic MailK. Moore | Proposed Standard | August 2004 |
| 3851 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Message SpecificationB. Ramsdell, Ed. · obsoleted by RFC 5751 | Proposed Standard | July 2004 |
| 3864 | Registration Procedures for Message Header FieldsG. Klyne, M. Nottingham, J. Mogul | Best Current Practice | September 2004 |
| 3885 | SMTP Service Extension for Message TrackingE. Allman, T. Hansen | Proposed Standard | September 2004 |
| 4021 | Registration of Mail and MIME Header FieldsG. Klyne, J. Palme | Proposed Standard | March 2005 |
| 4142 | Full-mode Fax Profile for Internet Mail (FFPIM)D. Crocker, G. Klyne | Proposed Standard | November 2005 |
| 4143 | Facsimile Using Internet Mail (IFAX) Service of ENUMK. Toyoda, D. Crocker | Proposed Standard | November 2005 |
| 4288 | Media Type Specifications and Registration ProceduresN. Freed, J. Klensin · obsoleted by RFC 6838 | Best Current Practice | December 2005 |
| 4289 | Multipurpose Internet Mail Extensions (MIME) Part Four: Registration ProceduresN. Freed, J. Klensin | Best Current Practice | December 2005 |
| 4356 | Mapping Between the Multimedia Messaging Service (MMS) and Internet MailR. Gellens | Proposed Standard | January 2006 |
| 4409 | Message Submission for MailR. Gellens, J. Klensin · obsoleted by RFC 6409 | Draft Standard | April 2006 |
| 4550 | Internet Email to Support Diverse Service Environments (Lemonade) ProfileS. Maes, A. Melnikov · obsoleted by RFC 5550 | Proposed Standard | June 2006 |
| 4880 | OpenPGP Message FormatJ. Callas, L. Donnerhacke, H. Finney, D. Shaw, R. Thayer · obsoleted by RFC 9580 | Proposed Standard | November 2007 |
| 4954 | SMTP Service Extension for AuthenticationR. Siemborski, Ed., A. Melnikov, Ed. | Proposed Standard | July 2007 |
| 5068 | Email Submission Operations: Access and Accountability RequirementsC. Hutzler, D. Crocker, P. Resnick, E. Allman, T. Finch | Best Current Practice | November 2007 |
| 5228 | Sieve: An Email Filtering LanguageP. Guenther, Ed., T. Showalter, Ed. | Proposed Standard | January 2008 |
| 5235 | Sieve Email Filtering: Spamtest and Virustest ExtensionsC. Daboo | Proposed Standard | January 2008 |
| 5248 | A Registry for SMTP Enhanced Mail System Status CodesT. Hansen, J. Klensin | Best Current Practice | June 2008 |
| 5321 | Simple Mail Transfer ProtocolJ. Klensin | Draft Standard | October 2008 |
| 5322 | Internet Message FormatP. Resnick, Ed. | Draft Standard | October 2008 |
| 5335 | Internationalized Email HeadersA. Yang, Ed. · obsoleted by RFC 6532 | Experimental | September 2008 |
| 5336 | SMTP Extension for Internationalized Email AddressesJ. Yao, Ed., W. Mao, Ed. · obsoleted by RFC 6531 | Experimental | September 2008 |