| 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 |
| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 3261 | SIP: Session Initiation ProtocolJ. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler | Proposed Standard | July 2002 |
| 3501 | INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1M. Crispin · obsoleted by RFC 9051 | Proposed Standard | March 2003 |
| 3550 | RTP: A Transport Protocol for Real-Time ApplicationsH. Schulzrinne, S. Casner, R. Frederick, V. Jacobson | Internet Standard | July 2003 |
| 3851 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Message SpecificationB. Ramsdell, Ed. · obsoleted by RFC 5751 | Proposed Standard | July 2004 |
| 3986 | Uniform Resource Identifier (URI): Generic SyntaxT. Berners-Lee, R. Fielding, L. Masinter | Internet Standard | January 2005 |
| 4240 | Basic Network Media Services with SIPE. Burger, Ed., J. Van Dyke, A. Spitzer | Informational | December 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 |
| 4467 | Internet Message Access Protocol (IMAP) - URLAUTH ExtensionM. Crispin | Proposed Standard | May 2006 |
| 4468 | Message Submission BURL ExtensionC. Newman | Proposed Standard | May 2006 |
| 4505 | Anonymous Simple Authentication and Security Layer (SASL) MechanismK. Zeilenga | Proposed Standard | June 2006 |
| 4566 | SDP: Session Description ProtocolM. Handley, V. Jacobson, C. Perkins · obsoleted by RFC 8866 | Proposed Standard | July 2006 |
| 4722 | Media Server Control Markup Language (MSCML) and ProtocolJ. Van Dyke, E. Burger, Ed., A. Spitzer · obsoleted by RFC 5022 | Informational | November 2006 |
| 5022 | Media Server Control Markup Language (MSCML) and ProtocolJ. Van Dyke, E. Burger, Ed., A. Spitzer | Informational | September 2007 |
| 5092 | IMAP URL SchemeA. Melnikov, Ed., C. Newman | Proposed Standard | November 2007 |
| 5234 | Augmented BNF for Syntax Specifications: ABNFD. Crocker, Ed., P. Overell | Internet Standard | January 2008 |
| 5246 | The Transport Layer Security (TLS) Protocol Version 1.2T. Dierks, E. Rescorla · obsoleted by RFC 8446, RFC 9846 | Proposed Standard | August 2008 |
| 5464 | The IMAP METADATA ExtensionC. Daboo | Proposed Standard | February 2009 |
| 5524 | Extended URLFETCH for Binary and Converted PartsD. Cridland | Proposed Standard | May 2009 |
| 5593 | Internet Message Access Protocol (IMAP) - URL Access Identifier ExtensionN. Cook | Proposed Standard | June 2009 |