| 793 | Transmission Control ProtocolJ. Postel · obsoleted by RFC 9293 | Internet Standard | September 1981 |
| 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 |
| 2595 | Using TLS with IMAP, POP3 and ACAPC. Newman | Proposed Standard | June 1999 |
| 2979 | Behavior of and Requirements for Internet FirewallsN. Freed | Informational | October 2000 |
| 3207 | SMTP Service Extension for Secure SMTP over Transport Layer SecurityP. Hoffman | Proposed Standard | February 2002 |
| 3501 | INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1M. Crispin · obsoleted by RFC 9051 | Proposed Standard | March 2003 |
| 3848 | ESMTP and LMTP Transmission Types RegistrationC. Newman | Draft Standard | July 2004 |
| 4033 | DNS Security Introduction and RequirementsR. Arends, R. Austein, M. Larson, D. Massey, S. Rose | Proposed Standard | March 2005 |
| 4346 | The Transport Layer Security (TLS) Protocol Version 1.1T. Dierks, E. Rescorla · obsoleted by RFC 5246 | Historic | April 2006 |
| 4422 | Simple Authentication and Security Layer (SASL)A. Melnikov, Ed., K. Zeilenga, Ed. | Proposed Standard | June 2006 |
| 4954 | SMTP Service Extension for AuthenticationR. Siemborski, Ed., A. Melnikov, Ed. | Proposed Standard | July 2007 |
| 5034 | The Post Office Protocol (POP3) Simple Authentication and Security Layer (SASL) Authentication MechanismR. Siemborski, A. Menon-Sen | Proposed Standard | July 2007 |
| 5068 | Email Submission Operations: Access and Accountability RequirementsC. Hutzler, D. Crocker, P. Resnick, E. Allman, T. Finch | Best Current Practice | 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 |
| 5280 | Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) ProfileD. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, W. Polk | Proposed Standard | May 2008 |
| 5321 | Simple Mail Transfer ProtocolJ. Klensin | Draft Standard | October 2008 |
| 5322 | Internet Message FormatP. Resnick, Ed. | Draft Standard | October 2008 |
| 6066 | Transport Layer Security (TLS) Extensions: Extension DefinitionsD. Eastlake 3rd | Proposed Standard | January 2011 |
| 6125 | Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)P. Saint-Andre, J. Hodges · obsoleted by RFC 9525 | Proposed Standard | March 2011 |
| 6186 | Use of SRV Records for Locating Email Submission/Access ServicesC. Daboo | Proposed Standard | March 2011 |
| 6335 | Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number RegistryM. Cotton, L. Eggert, J. Touch, M. Westerlund, S. Cheshire | Best Current Practice | August 2011 |
| 6409 | Message Submission for MailR. Gellens, J. Klensin | Internet Standard | November 2011 |
| 6698 | The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSAP. Hoffman, J. Schlyter | Proposed Standard | August 2012 |
| 7469 | Public Key Pinning Extension for HTTPC. Evans, C. Palmer, R. Sleevi | Proposed Standard | April 2015 |
| 7525 | Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)Y. Sheffer, R. Holz, P. Saint-Andre · obsoleted by RFC 9325 | Best Current Practice | May 2015 |
| 7672 | SMTP Security via Opportunistic DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS)V. Dukhovni, W. Hardaker | Proposed Standard | October 2015 |
| 7817 | Updated Transport Layer Security (TLS) Server Identity Check Procedure for Email-Related ProtocolsA. Melnikov | Proposed Standard | March 2016 |
| 7841 | RFC Streams, Headers, and BoilerplatesJ. Halpern, Ed., L. Daigle, Ed., O. Kolkman, Ed. | Informational | May 2016 |
| 8174 | Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsB. Leiba | Best Current Practice | May 2017 |