This file lists RFC's by number and title. "make" fetches the RFC's and adds references back to the source code where they are referenced. Not all RFC's in this list have been implemented yet. Also see IANA assignments, https://www.iana.org/protocols # Mail, message format, MIME 822 Standard for ARPA Internet Text Messages 1847 Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies 2046 Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types 2047 MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text 2049 Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples 2183 Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field 2231 MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations 3629 UTF-8, a transformation format of ISO 10646 3676 The Text/Plain Format and DelSp Parameters 3834 Recommendations for Automatic Responses to Electronic Mail 5234 Augmented BNF for Syntax Specifications: ABNF 5322 Internet Message Format 5598 Internet Mail Architecture 6854 Update to Internet Message Format to Allow Group Syntax in the "From:" and "Sender:" Header Fields 7405 Case-Sensitive String Support in ABNF 9228 Delivered-To Email Header Field https://www.iana.org/assignments/message-headers/message-headers.xhtml # SMTP 821 (obsoleted by RFC 2821) SIMPLE MAIL TRANSFER PROTOCOL 2821 (obsoleted by RFC 5321) Simple Mail Transfer Protocol 5321 Simple Mail Transfer Protocol 1870 SMTP Service Extension for Message Size Declaration 1985 SMTP Service Extension for Remote Message Queue Starting 2034 SMTP Service Extension for Returning Enhanced Error Codes 2852 Deliver By SMTP Service Extension 2920 SMTP Service Extension for Command Pipelining 2505 Anti-Spam Recommendations for SMTP MTAs 2852 Deliver By SMTP Service Extension 3207 SMTP Service Extension for Secure SMTP over Transport Layer Security (STARTTLS) 3030 SMTP Service Extensions for Transmission of Large and Binary MIME Messages 3461 Simple Mail Transfer Protocol (SMTP) Service Extension for Delivery Status Notifications (DSNs) 3462 (obsoleted by RFC 6522) The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages 3463 Enhanced Mail System Status Codes 3464 An Extensible Message Format for Delivery Status Notifications 3798 (obsoleted by RFC 8098) Message Disposition Notification 3848 ESMTP and LMTP Transmission Types Registration 3865 A No Soliciting Simple Mail Transfer Protocol (SMTP) Service Extension 3885 SMTP Service Extension for Message Tracking 3974 SMTP Operational Experience in Mixed IPv4/v6 Environments 4409 (obsoleted by RFC 6409) Message Submission for Mail 4468 Message Submission BURL Extension 4865 SMTP Submission Service Extension for Future Message Release 4954 SMTP Service Extension for Authentication 5068 Email Submission Operations: Access and Accountability Requirements 5248 A Registry for SMTP Enhanced Mail System Status Codes 5335 (obsoleted by RFC 6532) Internationalized Email Headers 5336 (obsoleted by RFC 6531) SMTP Extension for Internationalized Email Addresses 5337 (obsoleted by RFC 6533) Internationalized Delivery Status and Disposition Notifications 6008 Authentication-Results Registration for Differentiating among Cryptographic Results 6152 SMTP Service Extension for 8-bit MIME Transport 6409 Message Submission for Mail 6522 The Multipart/Report Media Type for the Reporting of Mail System Administrative Messages 6530 Overview and Framework for Internationalized Email 6531 SMTP Extension for Internationalized Email 6532 Internationalized Email Headers 6533 Internationalized Delivery Status and Disposition Notifications 6729 Indicating Email Handling States in Trace Fields 6857 Post-Delivery Message Downgrading for Internationalized Email Messages 7293 The Require-Recipient-Valid-Since Header Field and SMTP Service Extension 7372 Email Authentication Status Codes 7435 Opportunistic Security: Some Protection Most of the Time 7504 SMTP 521 and 556 Reply Codes 7505 A "Null MX" No Service Resource Record for Domains That Accept No Mail 8098 Message Disposition Notification 8601 Message Header Field for Indicating Message Authentication Status 8689 SMTP Require TLS Option # SPF 4408 (obsoleted by RFC 7208) Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1 6652 Sender Policy Framework (SPF) Authentication Failure Reporting Using the Abuse Reporting Format 7208 Sender Policy Framework (SPF) for Authorizing Use of Domains in Email, Version 1 7208-eid5436 errata: header-field FWS 7208-eid6721 errata: corrected smtp example response 7208-eid4751 errata (not verified): ptr mechanism 7208-eid5227 errata (not verified): ptr lookup order 7208-eid6595 errata (not verified): 2 void lookups vs exists 7208-eid6216 errata (not verified): ptr in multiple requirements example from appendix A.4 # DKIM 6376 DomainKeys Identified Mail (DKIM) Signatures 6376-eid4810 errata: q= qp-hdr-value 6376-eid5070 errata: tag-spec 4686 Analysis of Threats Motivating DomainKeys Identified Mail (DKIM) 4871 (obsoleted by RFC 6376) DomainKeys Identified Mail (DKIM) Signatures 5016 Requirements for a DomainKeys Identified Mail (DKIM) Signing Practices Protocol 5585 DomainKeys Identified Mail (DKIM) Service Overview 5672 (obsoleted by RFC 6376) DomainKeys Identified Mail (DKIM) Signatures -- Update 5863 DomainKeys Identified Mail (DKIM) Development, Deployment, and Operations 6377 DomainKeys Identified Mail (DKIM) and Mailing Lists 8032 Edwards-Curve Digital Signature Algorithm (EdDSA) 8301 Cryptographic Algorithm and Key Usage Update to DomainKeys Identified Mail (DKIM) 8463 A New Cryptographic Signature Method for DomainKeys Identified Mail (DKIM) # DMARC 7489 Domain-based Message Authentication, Reporting, and Conformance (DMARC) 7489-eid5440 errata: valid dmarc records with(out) semicolon 7489-eid6729 errata (not verified): publicsuffix list only for ICANN DOMAINS 7960 Interoperability Issues between Domain-based Message Authentication, Reporting, and Conformance (DMARC) and Indirect Email Flows 9091 Experimental Domain-Based Message Authentication, Reporting, and Conformance (DMARC) Extension for Public Suffix Domains # DKIM/SPF/DMARC 8616 Email Authentication for Internationalized Mail # Greylisting 6647 Email Greylisting: An Applicability Statement for SMTP # DNSBL/DNSWL 5782 DNS Blacklists and Whitelists 8904 DNS Whitelist (DNSWL) Email Authentication Method Extension # DANE 6698 The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA 7218 Adding Acronyms to Simplify Conversations about DNS-Based Authentication of Named Entities (DANE) 7671 The DNS-Based Authentication of Named Entities (DANE) Protocol: Updates and Operational Guidance 7672 SMTP Security via Opportunistic DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) # TLS-RPT 8460 SMTP TLS Reporting 8460-eid6241 Wrong example for JSON field "mx-host". # MTA-STS 8461 SMTP MTA Strict Transport Security (MTA-STS) # ARC 8617 The Authenticated Received Chain (ARC) Protocol # ARF 5965 An Extensible Format for Email Feedback Reports 6650 Creation and Use of Email Feedback Reports: An Applicability Statement for the Abuse Reporting Format (ARF) 6591 Authentication Failure Reporting Using the Abuse Reporting Format 6692 Source Ports in Abuse Reporting Format (ARF) Reports # IMAP 1730 (obsoleted by RFC 2060) INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4 2060 (obsoleted by RFC 3501) INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1 3501 (obsoleted by RFC 9051) INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1 9051 Internet Message Access Protocol (IMAP) - Version 4rev2 1733 DISTRIBUTED ELECTRONIC MAIL MODELS IN IMAP4 2087 IMAP4 QUOTA extension 2088 (obsoleted by RFC 7888) IMAP4 non-synchronizing literals 2152 UTF-7 A Mail-Safe Transformation Format of Unicode 2177 IMAP4 IDLE command 2180 IMAP4 Multi-Accessed Mailbox Practice 2193 IMAP4 Mailbox Referrals 2342 IMAP4 Namespace 2683 IMAP4 Implementation Recommendations 2971 IMAP4 ID extension 3348 (obsoleted by RFC 5258) The Internet Message Action Protocol (IMAP4) Child Mailbox Extension 3502 Internet Message Access Protocol (IMAP) - MULTIAPPEND Extension 3503 Message Disposition Notification (MDN) profile for Internet Message Access Protocol (IMAP) 3516 IMAP4 Binary Content Extension 3691 Internet Message Access Protocol (IMAP) UNSELECT command 4314 IMAP4 Access Control List (ACL) Extension 4315 Internet Message Access Protocol (IMAP) - UIDPLUS extension 4466 Collected Extensions to IMAP4 ABNF 4467 Internet Message Access Protocol (IMAP) - URLAUTH Extension 4469 Internet Message Access Protocol (IMAP) CATENATE Extension 4549 Synchronization Operations for Disconnected IMAP4 Clients 4551 (obsoleted by RFC 7162) IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization 4731 IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned 4959 IMAP Extension for Simple Authentication and Security Layer (SASL) Initial Client Response 4978 The IMAP COMPRESS Extension 5032 WITHIN Search Extension to the IMAP Protocol 5092 IMAP URL Scheme 5161 The IMAP ENABLE Extension 5162 (obsoleted by RFC 7162) IMAP4 Extensions for Quick Mailbox Resynchronization 5182 IMAP Extension for Referencing the Last SEARCH Result 5255 Internet Message Access Protocol Internationalization 5256 Internet Message Access Protocol - SORT and THREAD Extensions 5257 Internet Message Access Protocol - ANNOTATE Extension 5258 Internet Message Access Protocol version 4 - LIST Command Extensions 5259 Internet Message Access Protocol - CONVERT Extension 5267 Contexts for IMAP4 5464 The IMAP METADATA Extension 5465 The IMAP NOTIFY Extension 5466 IMAP4 Extension for Named Searches (Filters) 5524 Extended URLFETCH for Binary and Converted Parts 5530 IMAP Response Codes 5738 (obsoleted by RFC 6855) IMAP Support for UTF-8 5788 IMAP4 Keyword Registry 5819 IMAP4 Extension for Returning STATUS Information in Extended LIST 5957 Display-Based Address Sorting for the IMAP4 SORT Extension 6154 IMAP LIST Extension for Special-Use Mailboxes 6203 IMAP4 Extension for Fuzzy Search 6237 (obsoleted by RFC 7377) IMAP4 Multimailbox SEARCH Extension 6851 Internet Message Access Protocol (IMAP) - MOVE Extension 6855 IMAP Support for UTF-8 6858 Simplified POP and IMAP Downgrading for Internationalized Email 7162 IMAP Extensions: Quick Flag Changes Resynchronization (CONDSTORE) and Quick Mailbox Resynchronization (QRESYNC) 7162-eid5055 errata: space after untagged OK 7377 IMAP4 Multimailbox SEARCH Extension 7888 IMAP4 Non-synchronizing Literals 7889 The IMAP APPENDLIMIT Extension 8437 IMAP UNAUTHENTICATE Extension for Connection Reuse 8438 IMAP Extension for STATUS=SIZE 8440 IMAP4 Extension for Returning MYRIGHTS Information in Extended LIST 8457 IMAP "$Important" Keyword and "\Important" Special-Use Attribute 8474 IMAP Extension for Object Identifiers 8508 IMAP REPLACE Extension 8514 Internet Message Access Protocol (IMAP) - SAVEDATE Extension 8970 IMAP4 Extension: Message Preview Generation 9208 IMAP QUOTA Extension 9394 IMAP PARTIAL Extension for Paged SEARCH and FETCH 5198 Unicode Format for Network Interchange # Lemonade profile 4550 (obsoleted by RFC 5550) Internet Email to Support Diverse Service Environments (Lemonade) Profile 5383 Deployment Considerations for Lemonade-Compliant Mobile Email 5423 Internet Message Store Events 5442 LEMONADE Architecture - Supporting Open Mobile Alliance (OMA) Mobile Email (MEM) Using Internet Mail 5550 The Internet Email to Support Diverse Service Environments (Lemonade) Profile 5551 Lemonade Notifications Architecture # Mailing list 2369 The Use of URLs as Meta-Syntax for Core Mail List Commands and their Transport through Message Header Fields 2919 List-Id: A Structured Field and Namespace for the Identification of Mailing Lists # Sieve 3028 (obsoleted by RFC 5228) Sieve: A Mail Filtering Language 5228 Sieve: An Email Filtering Language 5804 A Protocol for Remotely Managing Sieve Scripts 3894 Sieve Extension: Copying Without Side Effects 5173 Sieve Email Filtering: Body Extension 5183 Sieve Email Filtering: Environment Extension 5229 Sieve Email Filtering: Variables Extension 5230 Sieve Email Filtering: Vacation Extension 5231 Sieve Email Filtering: Relational Extension 5232 Sieve Email Filtering: Imap4flags Extension 5233 Sieve Email Filtering: Subaddress Extension 5235 Sieve Email Filtering: Spamtest and Virustest Extensions 5260 Sieve Email Filtering: Date and Index Extensions 5293 Sieve Email Filtering: Editheader Extension 5429 Sieve Email Filtering: Reject and Extended Reject Extensions 5435 Sieve Email Filtering: Extension for Notifications 5437 Sieve Notification Mechanism: Extensible Messaging and Presence Protocol (XMPP) 5463 Sieve Email Filtering: Ihave Extension 5490 The Sieve Mail-Filtering Language -- Extensions for Checking Mailbox Status and Accessing Mailbox Metadata 5703 Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and Enclosure 5784 Sieve Email Filtering: Sieves and Display Directives in XML 6131 Sieve Vacation Extension: "Seconds" Parameter 6558 Sieve Extension for Converting Messages before Delivery 6609 Sieve Email Filtering: Include Extension 6785 Support for Internet Message Access Protocol (IMAP) Events in Sieve 8579 Sieve Email Filtering: Delivering to Special-Use Mailboxes 8580 Sieve Extension: File Carbon Copy (FCC) 9042 Sieve Email Filtering: Delivery by MAILBOXID 3431 (obsoleted by RFC 5231) Relational Extension 3598 (obsoleted by RFC 5233) Subaddress Extension 3685 (obsoleted by RFC 5235) Spamtest and VirusTest Extensions Also see http://sieve.info/documents # JMAP 8620 The JSON Meta Application Protocol (JMAP) 8621 The JSON Meta Application Protocol (JMAP) for Mail 8887 A JSON Meta Application Protocol (JMAP) Subprotocol for WebSocket 9007 Handling Message Disposition Notification with the JSON Meta Application Protocol (JMAP) 9219 S/MIME Signature Verification Extension to the JSON Meta Application Protocol (JMAP) 9425 JSON Meta Application Protocol (JMAP) for Quotas See implementation guide, https://jmap.io/server.html # Vouch by reference 5518 Vouch By Reference # TLS 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) 7525 Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) 8314 Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and Access 8996 Deprecating TLS 1.0 and TLS 1.1 8997 Deprecation of TLS 1.1 for Email Submission and Access # SASL 2104 HMAC: Keyed-Hashing for Message Authentication 2195 IMAP/POP AUTHorize Extension for Simple Challenge/Response 4013 (obsoleted by RFC 7613) SASLprep: Stringprep Profile for User Names and Passwords 4422 Simple Authentication and Security Layer (SASL) 4505 Anonymous Simple Authentication and Security Layer (SASL) Mechanism 4616 The PLAIN Simple Authentication and Security Layer (SASL) Mechanism 5802 Salted Challenge Response Authentication Mechanism (SCRAM) SASL and GSS-API Mechanisms 6331 Moving DIGEST-MD5 to Historic 7613 (obsoleted by RFC 8265) Preparation, Enforcement, and Comparison of Internationalized Strings Representing Usernames and Passwords 7677 SCRAM-SHA-256 and SCRAM-SHA-256-PLUS Simple Authentication and Security Layer (SASL) Mechanisms 8265 Preparation, Enforcement, and Comparison of Internationalized Strings Representing Usernames and Passwords # IDNA 3492 Punycode: A Bootstring encoding of Unicode for Internationalized Domain Names in Applications (IDNA) 5890 Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework 5891 Internationalized Domain Names in Applications (IDNA): Protocol 5892 The Unicode Code Points and Internationalized Domain Names for Applications (IDNA) 5893 Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA) 5894 Internationalized Domain Names for Applications (IDNA): Background, Explanation, and Rationale # ACME 8555 Automatic Certificate Management Environment (ACME) 8737 Automated Certificate Management Environment (ACME) TLS Application-Layer Protocol Negotiation (ALPN) Challenge Extension # DNS 1034 DOMAIN NAMES - CONCEPTS AND FACILITIES 1035 DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION 1101 DNS Encoding of Network Names and Other Types 1536 Common DNS Implementation Errors and Suggested Fixes 2181 Clarifications to the DNS Specification 2308 Negative Caching of DNS Queries (DNS NCACHE) 3363 Representing Internet Protocol version 6 (IPv6) Addresses in the Domain Name System (DNS) 3596 DNS Extensions to Support IP Version 6 3597 Handling of Unknown DNS Resource Record (RR) Types 4343 Domain Name System (DNS) Case Insensitivity Clarification 4592 The Role of Wildcards in the Domain Name System 5452 Measures for Making DNS More Resilient against Forged Answers 6604 xNAME RCODE and Status Bits Clarification 6672 DNAME Redirection in the DNS 6891 Extension Mechanisms for DNS (EDNS(0)) 6895 Domain Name System (DNS) IANA Considerations 7766 DNS Transport over TCP - Implementation Requirements 8020 NXDOMAIN: There Really Is Nothing Underneath 8482 Providing Minimal-Sized Responses to DNS Queries That Have QTYPE=ANY 8490 DNS Stateful Operations 8767 Serving Stale Data to Improve DNS Resiliency 9210 DNS Transport over TCP - Operational Requirements # DNSSEC 3225 Indicating Resolver Support of DNSSEC 3658 Delegation Signer (DS) Resource Record (RR) 4033 DNS Security Introduction and Requirements 4034 Resource Records for the DNS Security Extensions 4035 Protocol Modifications for the DNS Security Extensions 4470 Minimally Covering NSEC Records and DNSSEC On-line Signing 4956 DNS Security (DNSSEC) Opt-In 5155 DNS Security (DNSSEC) Hashed Authenticated Denial of Existence 5702 Use of SHA-2 Algorithms with RSA in DNSKEY and RRSIG Resource Records for DNSSEC 5933 Use of GOST Signature Algorithms in DNSKEY and RRSIG Resource Records for DNSSEC 6014 Cryptographic Algorithm Identifier Allocation for DNSSEC 6781 DNSSEC Operational Practices, Version 2 6840 Clarifications and Implementation Notes for DNS Security (DNSSEC) 8198 Aggressive Use of DNSSEC-Validated Cache 8624 Algorithm Implementation Requirements and Usage Guidance for DNSSEC 8749 Moving DNSSEC Lookaside Validation (DLV) to Historic Status 9077 NSEC and NSEC3: TTLs and Aggressive Use 9157 Revised IANA Considerations for DNSSEC 9276 Guidance for NSEC3 Parameter Settings # HTTP 2616 Hypertext Transfer Protocol -- HTTP/1.1 7230 Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing 9110 HTTP Semantics # Websockets 6455 The WebSocket Protocol # More 3339 Date and Time on the Internet: Timestamps 3986 Uniform Resource Identifier (URI): Generic Syntax 5617 (Historic) DomainKeys Identified Mail (DKIM) Author Domain Signing Practices (ADSP) 6186 (not used in practice) Use of SRV Records for Locating Email Submission/Access Services 7817 Updated Transport Layer Security (TLS) Server Identity Check Procedure for Email-Related Protocols # WebDAV 4918 HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) 3253 Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning) 3648 Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol 3744 Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol 4437 Web Distributed Authoring and Versioning (WebDAV) Redirect Reference Resources 5323 Web Distributed Authoring and Versioning (WebDAV) SEARCH 6578 Collection Synchronization for Web Distributed Authoring and Versioning (WebDAV) # CalDAV 4791 Calendaring Extensions to WebDAV (CalDAV) 5689 Extended MKCOL for Web Distributed Authoring and Versioning (WebDAV) 6638 Scheduling Extensions to CalDAV 6764 Locating Services for Calendaring Extensions to WebDAV (CalDAV) and vCard Extensions to WebDAV (CardDAV) 7809 Calendaring Extensions to WebDAV (CalDAV): Time Zones by Reference 7953 Calendar Availability # iCal 5545 Internet Calendaring and Scheduling Core Object Specification (iCalendar) 5546 iCalendar Transport-Independent Interoperability Protocol (iTIP) 6047 iCalendar Message-Based Interoperability Protocol (iMIP) 6868 Parameter Value Encoding in iCalendar and vCard 7529 Non-Gregorian Recurrence Rules in the Internet Calendaring and Scheduling Core Object Specification (iCalendar) 7986 New Properties for iCalendar 9073 Event Publishing Extensions to iCalendar 9074 "VALARM" Extensions for iCalendar 9253 Support for iCalendar Relationships 6321 xCal: The XML Format for iCalendar 7265 jCal: The JSON Format for iCalendar # CardDAV 6352 CardDAV: vCard Extensions to Web Distributed Authoring and Versioning (WebDAV) # vCard 2425 A MIME Content-Type for Directory Information 2426 vCard MIME Directory Profile 6350 vCard Format Specification 6351 xCard: vCard XML Representation 6473 vCard KIND:application 6474 vCard Format Extensions: Place of Birth, Place and Date of Death 6715 vCard Format Extensions: Representing vCard Extensions Defined by the Open Mobile Alliance (OMA) Converged Address Book (CAB) Group 6869 vCard KIND:device 7095 jCard: The JSON Format for vCard