| 1191 | Path MTU discoveryJ. Mogul, S. Deering | Draft Standard | November 1990 |
| 1939 | Post Office Protocol - Version 3J. Myers, M. Rose | Internet Standard | May 1996 |
| 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 |
| 2522 | Photuris: Session-Key Management ProtocolP. Karn, W. Simpson | Experimental | March 1999 |
| 2712 | Addition of Kerberos Cipher Suites to Transport Layer Security (TLS)A. Medvinsky, M. Hur | Proposed Standard | October 1999 |
| 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 |
| 4279 | Pre-Shared Key Ciphersuites for Transport Layer Security (TLS)P. Eronen, Ed., H. Tschofenig, Ed. | Proposed Standard | December 2005 |
| 4301 | Security Architecture for the Internet ProtocolS. Kent, K. Seo | Proposed Standard | December 2005 |
| 4340 | Datagram Congestion Control Protocol (DCCP)E. Kohler, M. Handley, S. Floyd | Proposed Standard | March 2006 |
| 4346 | The Transport Layer Security (TLS) Protocol Version 1.1T. Dierks, E. Rescorla · obsoleted by RFC 5246 | Historic | April 2006 |
| 4347 | Datagram Transport Layer SecurityE. Rescorla, N. Modadugu · obsoleted by RFC 6347 | Historic | April 2006 |
| 4443 | Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) SpecificationA. Conta, S. Deering, M. Gupta, Ed. | Internet Standard | March 2006 |
| 4492 | Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS)S. Blake-Wilson, N. Bolyard, V. Gupta, C. Hawk, B. Moeller · obsoleted by RFC 8422 | Informational | May 2006 |
| 4821 | Packetization Layer Path MTU DiscoveryM. Mathis, J. Heffner | Proposed Standard | March 2007 |
| 5216 | The EAP-TLS Authentication ProtocolD. Simon, B. Aboba, R. Hurst | Proposed Standard | March 2008 |
| 5238 | Datagram Transport Layer Security (DTLS) over the Datagram Congestion Control Protocol (DCCP)T. Phelan | Proposed Standard | May 2008 |
| 5246 | The Transport Layer Security (TLS) Protocol Version 1.2T. Dierks, E. Rescorla · obsoleted by RFC 8446, RFC 9846 | Proposed Standard | August 2008 |
| 5281 | Extensible Authentication Protocol Tunneled Transport Layer Security Authenticated Protocol Version 0 (EAP-TTLSv0)P. Funk, S. Blake-Wilson | Informational | August 2008 |
| 5288 | AES Galois Counter Mode (GCM) Cipher Suites for TLSJ. Salowey, A. Choudhury, D. McGrew | Proposed Standard | August 2008 |
| 5289 | TLS Elliptic Curve Cipher Suites with SHA-256/384 and AES Galois Counter Mode (GCM)E. Rescorla | Proposed Standard | August 2008 |
| 5406 | Guidelines for Specifying the Use of IPsec Version 2S. Bellovin | Best Current Practice | February 2009 |
| 5489 | ECDHE_PSK Cipher Suites for Transport Layer Security (TLS)M. Badra, I. Hajjeh | Informational | March 2009 |
| 5741 | RFC Streams, Headers, and BoilerplatesL. Daigle, Ed., O. Kolkman, Ed., IAB · obsoleted by RFC 7841 | Informational | December 2009 |
| 6298 | Computing TCP's Retransmission TimerV. Paxson, M. Allman, J. Chu, M. Sargent | Proposed Standard | June 2011 |