Table of header field registrations

Header name

Protocol

Purpose
Message-Context mail Type or context of message
Apparently-To mail Envelope recipients inserted my MTA
Approved-By mail Mailing list moderator who has approved message
Fax mail Fax number of the originator
Telefax mail Fax number of the originator
For-Approval mail Recipients for approval of this message
For-Comment mail Recipients for comment on this message
For-Handling mail Primary recipients for handling this message
Mail-System-Version mail Information about originating client software
Mailer mail Information about originating client software
Originating-Client mail Information about originating client software
X-Mailer mail Information about originating client software
X-Newsreader mail Information about originating client software
X-MimeOLE mail Information about originating client software
User-Agent mail Information about originating client software
Originator-Info mail Originator authentication information
Phone mail Phone number of the originator.
X-Envelope-From mail Mail envelope sender
Envelope-To mail Mail envelope recipient
X-Envelope-To mail Mail envelope recipient
X-Face mail Picture of the sender
X-RCPT-TO mail Mail envelope recipient
X-Sender mail Tentative message sender
X-X-Sender mail Extra-tentative message sender
Posted-To mail Nesgroup to which message was sent
X-Admin mail Submission server administrator mailbox
Errors-To mail Address for notifications to be sent
Return-Receipt-To mail Address for notifications to be sent
Read-Receipt-To mail Address for notifications to be sent
X-Confirm-reading-to mail Address for notifications to be sent
Return-Receipt-Requested mail Address for notifications to be sent
Register-Mail-Reply-Requested-By mail Address for notifications to be sent
Abuse-Reports-To mail Mailbox for reporting abuse
X-Complaints-To mail Mailbox for reporting abuse
X-Report-Abuse-To mail Mailbox for reporting abuse
Content-Alias mail Alternatice to Content-Location URI
Delivered-To mail Message loop detection
X-Loop mail Message loop detection
Translated-By mail Mailbox of translator
Translation-Of mail Reference source of translation
X-UIDL mail Message identifier within mailstore
X-URI mail URI of body part content
X-URL mail Location of body part content
X-IMAP mail IMAP UID
X-OriginalArrivalTime mail Time message was submitted
Precedence mail Message precedence indicator
X-MSMail-Priority mail Yet another priority indication.
X-Priority mail Message priority
Content-Length mail Size in bytes of body part
Content-Conversion mail Variant of 'Conversion:'
Content-Class mail Hierarchical content classification
Content-SGML-Entity mail SGML entity information
X-MIME-Autoconverted mail In-transit message conversion information
List-Digest mail URL for mailing list digest subscription
Mailing-List mail Mailing list information
X-Mailing-List mail Mailing list information
List-Software mail Mailing list software information
List-URL mail URL for mailing list information
X-Listserver mail List server software information
X-List-Host mail List server software information
Fcc mail File for copy of message
Speech-Act mail Speech act categorization of message
Status mail Message status in delivery system
X-No-Archive mail Do not archive publicly