| 3261 | SIP: Session Initiation ProtocolJ. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler | Proposed Standard | July 2002 |
| 3264 | An Offer/Answer Model with Session Description Protocol (SDP)J. Rosenberg, H. Schulzrinne | Proposed Standard | July 2002 |
| 3424 | IAB Considerations for UNilateral Self-Address Fixing (UNSAF) Across Network Address TranslationL. Daigle, Ed., IAB | Informational | November 2002 |
| 3435 | Media Gateway Control Protocol (MGCP) Version 1.0F. Andreasen, B. Foster | Informational | January 2003 |
| 3489 | STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs)J. Rosenberg, J. Weinberger, C. Huitema, R. Mahy · obsoleted by RFC 5389 | Proposed Standard | March 2003 |
| 3525 | Gateway Control Protocol Version 1C. Groves, Ed., M. Pantaleo, Ed., T. Anderson, Ed., T. Taylor, Ed. · obsoleted by RFC 5125 | Historic | June 2003 |
| 3711 | The Secure Real-time Transport Protocol (SRTP)M. Baugher, D. McGrew, M. Naslund, E. Carrara, K. Norrman | Proposed Standard | March 2004 |
| 4474 | Enhancements for Authenticated Identity Management in the Session Initiation Protocol (SIP)J. Peterson, C. Jennings · obsoleted by RFC 8224 | Proposed Standard | August 2006 |
| 4566 | SDP: Session Description ProtocolM. Handley, V. Jacobson, C. Perkins · obsoleted by RFC 8866 | Proposed Standard | July 2006 |
| 4787 | Network Address Translation (NAT) Behavioral Requirements for Unicast UDPF. Audet, Ed., C. Jennings | Best Current Practice | January 2007 |
| 5125 | Reclassification of RFC 3525 to HistoricT. Taylor | Informational | February 2008 |
| 5245 | Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer ProtocolsJ. Rosenberg · obsoleted by RFC 8445, RFC 8839 | Proposed Standard | April 2010 |
| 5389 | Session Traversal Utilities for NAT (STUN)J. Rosenberg, R. Mahy, P. Matthews, D. Wing · obsoleted by RFC 8489 | Proposed Standard | October 2008 |
| 5741 | RFC Streams, Headers, and BoilerplatesL. Daigle, Ed., O. Kolkman, Ed., IAB · obsoleted by RFC 7841 | Informational | December 2009 |
| 5751 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Message SpecificationB. Ramsdell, S. Turner · obsoleted by RFC 8551 | Proposed Standard | January 2010 |
| 5766 | Traversal Using Relays around NAT (TURN): Relay Extensions to Session Traversal Utilities for NAT (STUN)R. Mahy, P. Matthews, J. Rosenberg · obsoleted by RFC 8656 | Proposed Standard | April 2010 |
| 5853 | Requirements from Session Initiation Protocol (SIP) Session Border Control (SBC) DeploymentsJ. Hautakorpi, Ed., G. Camarillo, R. Penfield, A. Hawrylyshen, M. Bhatia | Informational | April 2010 |
| 6120 | Extensible Messaging and Presence Protocol (XMPP): CoreP. Saint-Andre | Proposed Standard | March 2011 |
| 6888 | Common Requirements for Carrier-Grade NATs (CGNs)S. Perreault, Ed., I. Yamagata, S. Miyakawa, A. Nakagawa, H. Ashida | Best Current Practice | April 2013 |