| 822 | STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGESD. Crocker · obsoleted by RFC 2822 | Internet Standard | August 1982 |
| 2385 | Protection of BGP Sessions via the TCP MD5 Signature OptionA. Heffernan · obsoleted by RFC 5925 | Proposed Standard | August 1998 |
| 2409 | The Internet Key Exchange (IKE)D. Harkins, D. Carrel · obsoleted by RFC 4306 | Historic | November 1998 |
| 2743 | Generic Security Service Application Program Interface Version 2, Update 1J. Linn | Proposed Standard | January 2000 |
| 3530 | Network File System (NFS) version 4 ProtocolS. Shepler, B. Callaghan, D. Robinson, R. Thurlow, C. Beame, M. Eisler, D. Noveck · obsoleted by RFC 7530 | Proposed Standard | April 2003 |
| 3720 | Internet Small Computer Systems Interface (iSCSI)J. Satran, K. Meth, C. Sapuntzakis, M. Chadalapaka, E. Zeidner · obsoleted by RFC 7143 | Proposed Standard | April 2004 |
| 3723 | Securing Block Storage Protocols over IPB. Aboba, J. Tseng, J. Walker, V. Rangan, F. Travostino | Proposed Standard | April 2004 |
| 3748 | Extensible Authentication Protocol (EAP)B. Aboba, L. Blunk, J. Vollbrecht, J. Carlson, H. Levkowetz, Ed. | Proposed Standard | June 2004 |
| 4120 | The Kerberos Network Authentication Service (V5)C. Neuman, T. Yu, S. Hartman, K. Raeburn | Proposed Standard | July 2005 |
| 4251 | The Secure Shell (SSH) Protocol ArchitectureT. Ylonen, C. Lonvick, Ed. | Proposed Standard | January 2006 |
| 4272 | BGP Security Vulnerabilities AnalysisS. Murphy | Informational | January 2006 |
| 4301 | Security Architecture for the Internet ProtocolS. Kent, K. Seo | Proposed Standard | December 2005 |
| 4322 | Opportunistic Encryption using the Internet Key Exchange (IKE)M. Richardson, D.H. Redelmeier | Informational | December 2005 |
| 4422 | Simple Authentication and Security Layer (SASL)A. Melnikov, Ed., K. Zeilenga, Ed. | Proposed Standard | June 2006 |
| 4430 | Kerberized Internet Negotiation of Keys (KINK)S. Sakane, K. Kamada, M. Thomas, J. Vilhuber | Proposed Standard | March 2006 |
| 4945 | The Internet IP Security PKI Profile of IKEv1/ISAKMP, IKEv2, and PKIXB. Korver | Proposed Standard | August 2007 |
| 4953 | Defending TCP Against Spoofing AttacksJ. Touch | Informational | July 2007 |
| 5041 | Direct Data Placement over Reliable TransportsH. Shah, J. Pinkerton, R. Recio, P. Culley | Proposed Standard | October 2007 |
| 5056 | On the Use of Channel Bindings to Secure ChannelsN. Williams | Proposed Standard | November 2007 |
| 5201 | Host Identity ProtocolR. Moskowitz, P. Nikander, P. Jokela, Ed., T. Henderson · obsoleted by RFC 7401 | Experimental | April 2008 |
| 5246 | The Transport Layer Security (TLS) Protocol Version 1.2T. Dierks, E. Rescorla · obsoleted by RFC 8446, RFC 9846 | Proposed Standard | August 2008 |
| 5386 | Better-Than-Nothing Security: An Unauthenticated Mode of IPsecN. Williams, M. Richardson | Proposed Standard | November 2008 |