Message Headers
- Last Updated
- 2024-09-03
- Available Formats
-
XML
HTML
Plain text
Registries included below
- Permanent Message Header Field Names
- Provisional Message Header Field Names
- Content-Translation-Type Header Field Values
Permanent Message Header Field Names
- Registration Procedure(s)
-
Expert Review
- Expert(s)
-
Graham Klyne
- Reference
- [RFC3864]
- Note
-
[RFC5504] specified that no new header fields be registered that begin with "Downgraded-". That restriction is now lifted, per [RFC6857].
- Note
-
HTTP field name registrations have been moved to [https://www.iana.org/assignments/http-fields] per [RFC9110].
- Available Formats
-
CSV
Header Field Name | Template | Protocol | Status | Reference |
---|---|---|---|---|
Accept-Language | [RFC4021] | |||
Also-Control | netnews | obsoleted | [RFC1849][RFC5536] | |
Alternate-Recipient | [RFC4021] | |||
Approved | netnews | standard | [RFC5536] | |
ARC-Authentication-Results | experimental | [RFC8617] | ||
ARC-Message-Signature | experimental | [RFC8617] | ||
ARC-Seal | experimental | [RFC8617] | ||
Archive | netnews | standard | [RFC5536] | |
Archived-At | standard | [RFC5064] | ||
Archived-At | netnews | standard | [RFC5064] | |
Article-Names | netnews | obsoleted | [RFC1849][RFC5536] | |
Article-Updates | netnews | obsoleted | [RFC1849][RFC5536] | |
Authentication-Results | standard | [RFC8601] | ||
Auto-Submitted | standard | [RFC3834 section 5] | ||
Autoforwarded | [RFC4021] | |||
Autosubmitted | [RFC4021] | |||
Base | MIME | obsoleted | [RFC1808][RFC2068 Section 14.11] | |
Bcc | standard | [RFC5322] | ||
Body | none | reserved | [RFC6068] | |
Cancel-Key | netnews | standard | [RFC8315] | |
Cancel-Lock | netnews | standard | [RFC8315] | |
Cc | standard | [RFC5322] | ||
Comments | standard | [RFC5322] | ||
Comments | netnews | standard | [RFC5536][RFC5322] | |
Content-Alternative | MIME | [RFC4021] | ||
Content-Base | MIME | obsoleted | [RFC2110][RFC2557] | |
Content-Description | MIME | [RFC4021] | ||
Content-Disposition | MIME | [RFC4021] | ||
Content-Duration | MIME | [RFC4021] | ||
Content-features | MIME | [RFC4021] | ||
Content-ID | MIME | [RFC4021] | ||
Content-Identifier | [RFC4021] | |||
Content-Language | MIME | [RFC4021] | ||
Content-Location | MIME | [RFC4021] | ||
Content-MD5 | MIME | [RFC4021] | ||
Content-Return | [RFC4021] | |||
Content-Transfer-Encoding | MIME | [RFC4021] | ||
Content-Translation-Type | MIME | standard | [RFC8255] | |
Content-Type | MIME | [RFC4021] | ||
Control | netnews | standard | [RFC5536] | |
Conversion | [RFC4021] | |||
Conversion-With-Loss | [RFC4021] | |||
DL-Expansion-History | [RFC4021] | |||
Date | standard | [RFC5322] | ||
Date | netnews | standard | [RFC5536][RFC5322] | |
Date-Received | netnews | obsoleted | [RFC850][RFC5536] | |
Deferred-Delivery | [RFC4021] | |||
Delivery-Date | [RFC4021] | |||
Discarded-X400-IPMS-Extensions | [RFC4021] | |||
Discarded-X400-MTS-Extensions | [RFC4021] | |||
Disclose-Recipients | [RFC4021] | |||
Disposition-Notification-Options | [RFC4021] | |||
Disposition-Notification-To | [RFC4021] | |||
Distribution | netnews | standard | [RFC5536] | |
DKIM-Signature | standard | [RFC6376] | ||
Downgraded-Bcc | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Cc | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Disposition-Notification-To | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Final-Recipient | standard | [RFC6857 Section 3.1.10] | ||
Downgraded-From | obsoleted | [RFC5504][RFC6857 Section 3.1.10] | ||
Downgraded-In-Reply-To | standard | [RFC6857 Section 3.1.10] | ||
Downgraded-Mail-From | obsoleted | [RFC5504][RFC6857 Section 3.1.10] | ||
Downgraded-Message-Id | standard | [RFC6857 Section 3.1.10] | ||
Downgraded-Original-Recipient | standard | [RFC6857 Section 3.1.10] | ||
Downgraded-Rcpt-To | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-References | standard | [RFC6857 Section 3.1.10] | ||
Downgraded-Reply-To | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-Bcc | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-Cc | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-From | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-Reply-To | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-Sender | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Resent-To | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Return-Path | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-Sender | obsoleted | [RFC5504][RFC6857] | ||
Downgraded-To | obsoleted | [RFC5504][RFC6857] | ||
Encoding | [RFC4021] | |||
Encrypted | [RFC4021] | |||
Expires | [RFC4021] | |||
Expires | netnews | standard | [RFC5536] | |
Expiry-Date | [RFC4021] | |||
Followup-To | netnews | standard | [RFC5536] | |
From | standard | [RFC5322][RFC6854] | ||
From | netnews | standard | [RFC5536][RFC5322] | |
Generate-Delivery-Report | [RFC4021] | |||
Importance | [RFC4021] | |||
In-Reply-To | standard | [RFC5322] | ||
Incomplete-Copy | [RFC4021] | |||
Injection-Date | netnews | standard | [RFC5536] | |
Injection-Info | netnews | standard | [RFC5536] | |
Keywords | standard | [RFC5322] | ||
Keywords | netnews | standard | [RFC5536][RFC5322] | |
Language | [RFC4021] | |||
Latest-Delivery-Time | [RFC4021] | |||
Lines | netnews | deprecated | [RFC5536][RFC3977] | |
List-Archive | [RFC4021] | |||
List-Help | [RFC4021] | |||
List-ID | [RFC4021] | |||
List-Owner | [RFC4021] | |||
List-Post | [RFC4021] | |||
List-Subscribe | [RFC4021] | |||
List-Unsubscribe | perm/list-unsubscribe | [RFC4021] | ||
List-Unsubscribe-Post | standard | [RFC8058] | ||
Message-Context | [RFC4021] | |||
Message-ID | standard | [RFC5322] | ||
Message-ID | netnews | standard | [RFC5536][RFC5322] | |
Message-Type | [RFC4021] | |||
MIME-Version | MIME | [RFC4021] | ||
MMHS-Exempted-Address | [RFC6477][ACP123 Appendix A1.1 and Appendix B.105] | |||
MMHS-Extended-Authorisation-Info | [RFC6477][ACP123 Appendix A1.2 and Appendix B.106] | |||
MMHS-Subject-Indicator-Codes | [RFC6477][ACP123 Appendix A1.3 and Appendix B.107] | |||
MMHS-Handling-Instructions | [RFC6477][ACP123 Appendix A1.4 and Appendix B.108] | |||
MMHS-Message-Instructions | [RFC6477][ACP123 Appendix A1.5 and Appendix B.109] | |||
MMHS-Codress-Message-Indicator | [RFC6477][ACP123 Appendix A1.6 and Appendix B.110] | |||
MMHS-Originator-Reference | [RFC6477][ACP123 Appendix A1.7 and Appendix B.111] | |||
MMHS-Primary-Precedence | [RFC6477][ACP123 Appendix A1.8 and Appendix B.101] | |||
MMHS-Copy-Precedence | [RFC6477][ACP123 Appendix A1.9 and Appendix B.102] | |||
MMHS-Message-Type | [RFC6477][ACP123 Appendix A1.10 and Appendix B.103] | |||
MMHS-Other-Recipients-Indicator-To | [RFC6477][ACP123 Appendix A1.12 and Appendix B.113] | |||
MMHS-Other-Recipients-Indicator-CC | [RFC6477][ACP123 Appendix A1.12 and Appendix B.113] | |||
MMHS-Acp127-Message-Identifier | [RFC6477][ACP123 Appendix A1.14 and Appendix B.116] | |||
MMHS-Originator-PLAD | [RFC6477][ACP123 Appendix A1.15 and Appendix B.117] | |||
MT-Priority | standard | [RFC6758] | ||
Newsgroups | netnews | standard | [RFC5536] | |
NNTP-Posting-Date | netnews | obsoleted | [RFC5536] | |
NNTP-Posting-Host | netnews | obsoleted | [RFC2980][RFC5536] | |
Obsoletes | [RFC4021] | |||
Organization | informational | [RFC7681] | ||
Organization | netnews | standard | [RFC5536] | |
Original-Encoded-Information-Types | [RFC4021] | |||
Original-From | standard | [RFC5703] | ||
Original-Message-ID | [RFC4021] | |||
Original-Recipient | perm/original-recipient | standard | [RFC3798][RFC5337] | |
Original-Sender | netnews | standard | [RFC5537] | |
Originator-Return-Address | [RFC4021] | |||
Original-Subject | standard | [RFC5703] | ||
Path | netnews | standard | [RFC5536] | |
PICS-Label | [RFC4021] | |||
Posting-Version | netnews | obsoleted | [RFC850][RFC5536] | |
Prevent-NonDelivery-Report | [RFC4021] | |||
Priority | [RFC4021] | |||
Received | standard | [RFC5322][RFC5321] | ||
Received-SPF | standard | [RFC7208] | ||
References | standard | [RFC5322] | ||
References | netnews | standard | [RFC5536][RFC5322] | |
Relay-Version | netnews | obsoleted | [RFC850][RFC5536] | |
Reply-By | [RFC4021] | |||
Reply-To | standard | [RFC5322] | ||
Reply-To | netnews | standard | [RFC5536][RFC5322] | |
Require-Recipient-Valid-Since | standard | [RFC7293] | ||
Resent-Bcc | standard | [RFC5322] | ||
Resent-Cc | standard | [RFC5322] | ||
Resent-Date | standard | [RFC5322] | ||
Resent-From | standard | [RFC5322][RFC6854] | ||
Resent-Message-ID | standard | [RFC5322] | ||
Resent-Reply-To | obsoleted | [RFC5322] | ||
Resent-Sender | standard | [RFC5322][RFC6854] | ||
Resent-To | standard | [RFC5322] | ||
Return-Path | standard | [RFC5322] | ||
See-Also | netnews | obsoleted | [RFC1849][RFC5536] | |
Sender | standard | [RFC5322][RFC6854] | ||
Sender | netnews | standard | [RFC5536][RFC5322] | |
Sensitivity | [RFC4021] | |||
Solicitation | [RFC3865] | |||
Subject | standard | [RFC5322] | ||
Subject | netnews | standard | [RFC5536][RFC5322] | |
Summary | netnews | standard | [RFC5536] | |
Supersedes | [RFC4021] | |||
Supersedes | netnews | standard | [RFC5536][RFC2156] | |
TLS-Report-Domain | standard | [RFC8460] | ||
TLS-Report-Submitter | standard | [RFC8460] | ||
TLS-Required | standard | [RFC8689] | ||
To | standard | [RFC5322] | ||
User-Agent | netnews | standard | [RFC5536][RFC2616] | |
VBR-Info | standard | [RFC5518] | ||
X400-Content-Identifier | [RFC4021] | |||
X400-Content-Return | [RFC4021] | |||
X400-Content-Type | [RFC4021] | |||
X400-MTS-Identifier | [RFC4021] | |||
X400-Originator | [RFC4021] | |||
X400-Received | [RFC4021] | |||
X400-Recipients | [RFC4021] | |||
X400-Trace | [RFC4021] | |||
Xref | netnews | standard | [RFC5536] |
Provisional Message Header Field Names
- Registration Procedure(s)
-
Expert Review
- Expert(s)
-
Graham Klyne
- Reference
- [RFC3864]
- Note
-
Registration of a Provisional Message Header Field does not of itself imply any kind of endorsement by the IETF, IANA or any other body.
- Note
-
HTTP field name registrations have been moved to [https://www.iana.org/assignments/http-fields] per [RFC9110].
- Available Formats
-
CSV
Header Field Name | Template | Protocol | Status | Reference |
---|---|---|---|---|
Apparently-To | prov/apparently-to | [RFC2076] | ||
Author | [RFC9057] | |||
CFBL-Address | [RFC9477] | |||
CFBL-Feedback-ID | [RFC9477] | |||
Delivered-To | [RFC9228] | |||
EDIINT-Features | [RFC6017] | |||
Eesst-Version | [RFC7681] | |||
Errors-To | prov/errors-to | [RFC2076] | ||
Face | prov/face | [https://quimby.gnus.org/circus/face] | ||
Face | prov/face | netnews | [https://quimby.gnus.org/circus/face] | |
Form-Sub | [draft-levine-mailbomb-header] | |||
Jabber-ID | prov/jabber-id | [RFC7259] | ||
Jabber-ID | prov/jabber-id | netnews | [RFC7259] | |
MMHS-Authorizing-Users | [RFC7912] | |||
Privicon | [draft-koenig-privicons] | |||
SIO-Label | [RFC7444] | |||
SIO-Label-History | [RFC7444] | |||
Wrong-Recipient | prov/wrong-recipient | [draft-ietf-mailmaint-wrong-recipient-00] | ||
X-Archived-At | prov/x-archived-at | deprecated | [RFC5064] | |
X-Archived-At | prov/x-archived-at | netnews | deprecated | [RFC5064] |
X-Face | prov/x-face | [https://purl.org/x-face-spec] | ||
X-Face | prov/x-face | netnews | [https://purl.org/x-face-spec] | |
X-Mittente | [RFC6109] | |||
X-PGP-Sig | prov/x-pgp-sig | netnews | [ftp://ftp.isc.org/pub/pgpcontrol/FORMAT][https://ftp.isc.org/pub/pgpcontrol/FORMAT] | |
X-Ricevuta | [RFC6109] | |||
X-Riferimento-Message-ID | [RFC6109] | |||
X-TipoRicevuta | [RFC6109] | |||
X-Trasporto | [RFC6109] | |||
X-VerificaSicurezza | [RFC6109] |
Content-Translation-Type Header Field Values
- Registration Procedure(s)
-
Specification Required
- Expert(s)
-
Nik Tomkinson
- Reference
- [RFC8255]
- Available Formats
-
CSV
Value | Description | Reference |
---|---|---|
original | Content in the original language | [RFC8255] |
human | Content that has been translated by a human translator or a human has checked and corrected an automated translation | [RFC8255] |
automated | Content that has been translated by an electronic agent without proofreading or subsequent correction | [RFC8255] |