| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 2246 | The TLS Protocol Version 1.0T. Dierks, C. Allen · obsoleted by RFC 4346 | Historic | January 1999 |
| 2396 | Uniform Resource Identifiers (URI): Generic SyntaxT. Berners-Lee, R. Fielding, L. Masinter · obsoleted by RFC 3986 | Draft Standard | August 1998 |
| 2401 | Security Architecture for the Internet ProtocolS. Kent, R. Atkinson · obsoleted by RFC 4301 | Proposed Standard | November 1998 |
| 2486 | The Network Access IdentifierB. Aboba, M. Beadles · obsoleted by RFC 4282 | Proposed Standard | January 1999 |
| 2828 | Internet Security GlossaryR. Shirey · obsoleted by RFC 4949 | Informational | May 2000 |
| 2833 | RTP Payload for DTMF Digits, Telephony Tones and Telephony SignalsH. Schulzrinne, S. Petrack · obsoleted by RFC 4733, RFC 4734 | Proposed Standard | May 2000 |
| 2916 | E.164 number and DNSP. Faltstrom · obsoleted by RFC 3761 | Proposed Standard | September 2000 |
| 3261 | SIP: Session Initiation ProtocolJ. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler | Proposed Standard | July 2002 |
| 3263 | Session Initiation Protocol (SIP): Locating SIP ServersJ. Rosenberg, H. Schulzrinne | Proposed Standard | July 2002 |
| 3264 | An Offer/Answer Model with Session Description Protocol (SDP)J. Rosenberg, H. Schulzrinne | Proposed Standard | July 2002 |
| 3265 | Session Initiation Protocol (SIP)-Specific Event NotificationA. B. Roach · obsoleted by RFC 6665 | Proposed Standard | July 2002 |
| 3310 | Hypertext Transfer Protocol (HTTP) Digest Authentication Using Authentication and Key Agreement (AKA)A. Niemi, J. Arkko, V. Torvinen | Informational | September 2002 |
| 3313 | Private Session Initiation Protocol (SIP) Extensions for Media AuthorizationW. Marshall, Ed. | Informational | January 2003 |
| 3319 | Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) ServersH. Schulzrinne, B. Volz | Proposed Standard | July 2003 |
| 3323 | A Privacy Mechanism for the Session Initiation Protocol (SIP)J. Peterson | Proposed Standard | December 2002 |
| 3325 | Private Extensions to the Session Initiation Protocol (SIP) for Asserted Identity within Trusted NetworksC. Jennings, J. Peterson, M. Watson | Informational | December 2002 |
| 3515 | The Session Initiation Protocol (SIP) Refer MethodR. Sparks | Proposed Standard | April 2003 |
| 3665 | Session Initiation Protocol (SIP) Basic Call Flow ExamplesA. Johnston, S. Donovan, R. Sparks, C. Cunningham, K. Summers | Best Current Practice | January 2004 |
| 3666 | Session Initiation Protocol (SIP) Public Switched Telephone Network (PSTN) Call FlowsA. Johnston, S. Donovan, R. Sparks, C. Cunningham, K. Summers | Best Current Practice | January 2004 |
| 3680 | A Session Initiation Protocol (SIP) Event Package for RegistrationsJ. Rosenberg | Proposed Standard | March 2004 |
| 3891 | The Session Initiation Protocol (SIP) "Replaces" HeaderR. Mahy, B. Biggs, R. Dean | Proposed Standard | September 2004 |
| 3966 | The tel URI for Telephone NumbersH. Schulzrinne | Proposed Standard | December 2004 |