Network Working Group G. Klyne
Internet-Draft MIMEsweeper Group
Expires: March 28, 2002 Sep 27, 2001
Registration procedures for message headers
draft-klyne-msghdr-registry-00
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on March 28, 2002.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This specification defines registration procedures for the message
headers used by Internet mail, newsgroup feeds, HTTP and other
Internet applications.
Discussion of this document
Please send comments to <ietf-822@imc.org>. To subscribe to this
list, send a message with the body 'subscribe' to <ietf-822-
request@imc.org>.
Klyne Expires March 28, 2002 [Page 1]
Internet-Draft Message header registration Sep 2001
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Structure of this document . . . . . . . . . . . . . . . . . . 3
1.2 Document terminology and conventions . . . . . . . . . . . . . 3
2. Message headers . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Standard and non-standard headers . . . . . . . . . . . . . . 4
2.2 Definitions of message headers . . . . . . . . . . . . . . . . 4
3. Registration procedure . . . . . . . . . . . . . . . . . . . . 4
3.1 Header specification . . . . . . . . . . . . . . . . . . . . . 5
3.2 Registration template . . . . . . . . . . . . . . . . . . . . 5
3.3 Submission of registration . . . . . . . . . . . . . . . . . . 6
3.4 Change control . . . . . . . . . . . . . . . . . . . . . . . . 6
3.5 Comments on header definitions . . . . . . . . . . . . . . . . 6
3.6 Location of message header registry . . . . . . . . . . . . . 6
4. Initial registrations . . . . . . . . . . . . . . . . . . . . 6
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 7
6. Security considerations . . . . . . . . . . . . . . . . . . . 7
References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 9
A. Revision history . . . . . . . . . . . . . . . . . . . . . . . 9
A.1 draft-klyne-msghdr-registry-00 . . . . . . . . . . . . . . . . 9
B. Todo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 11
Klyne Expires March 28, 2002 [Page 2]
Internet-Draft Message header registration Sep 2001
1. Introduction
This specification defines registration procedures for the message
headers used by Internet mail, newsgroup feeds, HTTP and other
Internet applications.
The primary specification for Internet message headers is the
Internet mail message format specification, RFC 2822 [21], but there
are many other Internet standards track documents that define
additional headers within the same namespace, notably MIME [6] and
related specifications. Other Internet applications that use MIME,
such as newsgroup feeds and HTTP web access, also use many of the
same headers.
Although in principle each application defines its own set of valid
headers, exchange of messages between applications (e.g. mail to
news gateways), common use of MIME encapsulation, and the possibility
of common processing for various message types (e.g. a common
message archive and retrieval facility) makes it desirable to have a
single point of reference for standardized headers. The message
header registry defined here serves that purpose.
1.1 Structure of this document
Section Section 2 discusses the purpose of this specification, and
indicates some sources of information about defined message headers.
Section Section 3 defines the message header registry, and sets out
requirements and procedures for creating entries in it.
1.2 Document terminology and conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [9].
NOTE: indented comments like this provide additional nonessential
information about the rationale behind this document.
[[[Editorial comments and questions about outstanding issues are
provided in triple brackets like this. These working comments should
be resolved and removed prior to final publication.]]]
2. Message headers
Klyne Expires March 28, 2002 [Page 3]
Internet-Draft Message header registration Sep 2001
2.1 Standard and non-standard headers
Many message headers are defined in standards-track documents, which
means they have been subjected to a process of community review and
achieved consensus that they provide a useful and well-founded
capability. Many other headers have been defined and adopted for
private use.
The registry defined here is intended for headers defined in IETF
standards-track documents, or those that have achieved a comparable
level of community review. Thus, the assignment policy for
registration of new message headers is [[[ IETF consensus | Standards
action ]]], as defined by RFC 2434 [17].
A registry for non-standards-track message headers is at best
informational, and at least two such sources of information already
exist:
o RFC 2076 [7], as updated [24], contains a list of commonly used
message headers, and
o Dan Bernstein maintains a list of standard and non-standard mail
message headers [25].
2.2 Definitions of message headers
RFC 2822 [21] defines a general syntax for Internet message headers.
It also defines a number of headers for use with Internet mail.
Additional header names are defined in a variety of standards-track
RFC documents, including: RFC 1036 [1], RFC 1496 [2], RFC 1505 [3],
RFC 1766 [4], RFC 1864 [5], RFC 2156 [11], RFC 2183 [12], RFC 2045
[6], RFC 2110 [8], RFC 2298 [13], RFC 2369 [14], RFC 2421 [16], RFC
2821 [20], RFC 2912 [22] and RFC 2919 [23].
Internet applications that use (some of) these message headers
include Internet mail [20][21], NNTP newsgroup feeds [1], HTTP web
access [18] and any other that uses MIME [6] encapsulation of message
content.
3. Registration procedure
The procedure for registering a message header is:
1. Construct a header specification
2. Prepare a registration template
Klyne Expires March 28, 2002 [Page 4]
Internet-Draft Message header registration Sep 2001
3. Submit the registration template
3.1 Header specification
Registration of a new message header starts with construction of a
proposal that describes the syntax, semantics and intended use of the
header. This proposal MUST be published as an RFC.
A registered header name MUST conform to the syntax defined by RFC
2822, section 3.6.8, for "field name". Further, the "." character is
reserved to indicate a naming sub-structure and MUST NOT be included
in any registered header name. Currently, no specific sub-structure
is defined; if used, any such structure MUST be defined by a
standards track RFC document.
It is further RECOMMENDED that characters in a registered message
header name are restricted to those characters that can be used
without escaping in a URI [15], namely upper- or lower-case ASCII
letters, decimal digits, "(", ")", "+", ",", "-", "=", "@", ";", "$",
"_", "!", "*" and "'".
The name of a registered header MUST be unique; if an name is already
assigned to an existing registered header name, some other name must
be chosen.
Header names beginning with "X-" or "x-" are reserved for private
use, and MUST NOT be registered or defined normatively by a standards
track RFC.
3.2 Registration template
The registration template for a message header is typically contained
in the defining document, or may be prepared separately.
The registration template for a message header contains the following
information:
Header name:
The name requested for the new header. This MUST conform to the
header specification details above.
Specification document:
A reference to the standards track RFC that defined the header.
Intended use:
Specify "general", "mail", "news", "http", "MIME" or cite any
other standards-track RFC defining the protocol with which the
Klyne Expires March 28, 2002 [Page 5]
Internet-Draft Message header registration Sep 2001
header is intended to be used.
Related information:
Optionally, citations to additional documents containing further
information relevant to the defined message header.
3.3 Submission of registration
The registration is submitted for incorporation in the IANA message
header registry by one of the following means:
o An IANA considerations section in the defining RFC, calling for
registration of the message header and referencing the
registration template within the same document. Registration of
the header is processed as part of the RFC publication process.
o Sending the registration template in an email to the designated
email address [26]. IANA will register the message header if the
requested name and the specification document meet the criteria
stated.
3.4 Change control
Change control of a header registration is subject to the same
conditions as the initial registration; i.e. publication of an IESG-
approved RFC.
3.5 Comments on header definitions
Comments on registered message headers should be sent to the IETF-822
email discussion list [26].
Comments on proposed message headers should preferably be sent to the
discusion forum for the specification concerned. They may also be
sent to the IETF-822 list [26] if they concern wider implications
than are addressed by the specification document.
3.6 Location of message header registry
The message header registry is accessible from IANA's web site [27].
4. Initial registrations
This specification calls for initial registration of all message
headers defined in existing standards-track documents. A list of
such headers can be found in RFC 2076 [7] and updates [24]. Section
Klyne Expires March 28, 2002 [Page 6]
Internet-Draft Message header registration Sep 2001
Section 2.2 of this document contains a list of standards-track
specifications that define message headers.
[[[Need to provide list of headers+documents here for initial
registration?]]]
5. IANA considerations
This specification calls for:
o A new IANA registry for message headers, per section Section 3 of
this document. The policy for inclusion in this registry is [[[
IETF consensus | Standards action ]]], per RFC 2434 [17].
o Initial message header registrations, per section Section 4 of
this document.
6. Security considerations
No security considerations are introduced by this specification
beyond those already inherrent in the use of message headers.
References
[1] Horton, M. and R. Adams, "Standard for interchange of USENET
messages", RFC 1036, December 1987.
[2] Alvestrand, H., Jordan, K. and J. Romaguera, "Rules for
downgrading messages from X.400/88 to X.400/84 when MIME
content-types are present in the messages", RFC 1496, August
1993.
[3] Costanzo, A., Robinson, D. and R. Ullmann, "Encoding Header
Field for Internet Messages", RFC 1505, August 1993.
[4] Alvestrand, H., "Tags for the Identification of Languages", RFC
1766, March 1995.
[5] Myers, J. and M. Rose, "The Content-MD5 Header Field", RFC
1864, October 1995.
[6] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies",
RFC 2045, November 1996.
[7] Palme, J., "Common Internet Message Headers", RFC 2076,
February 1997.
Klyne Expires March 28, 2002 [Page 7]
Internet-Draft Message header registration Sep 2001
[8] Palme, J. and A. Hopmann, "MIME E-mail Encapsulation of
Aggregate Documents, such as HTML (MHTML)", RFC 2110, March
1997.
[9] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[10] Moats, R., "URN Syntax", RFC 2141, May 1997.
[11] Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay): Mapping
between X.400 and RFC 822/MIME", RFC 2156, January 1998.
[12] Moore, K., Troost, R. and S. Dorner, "Communicating
Presentation Information in Internet Messages: The Content-
Disposition Header Field", RFC 2183, August 1997.
[13] Fajman, R., "An Extensible Message Format for Message
Disposition Notifications", RFC 2298, March 1998.
[14] Baer, J. and G. Neufeld, "The Use of URLs as Meta-Syntax for
Core Mail List Commands and their Transport through Message
Header Fields", RFC 2369, July 1998.
[15] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396, August
1998.
[16] Parsons, G. and G. Vaudreuil, "Voice Profile for Internet Mail
- version 2", RFC 2421, September 1998.
[17] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October
1998.
[18] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L.,
Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol --
HTTP/1.1", RFC 2616, June 1999.
[19] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[20] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, April
2001.
[21] Resnick, P., "Internet Message Format", RFC 2822, April 2001.
[22] Klyne, G., "Indicating Media Features for MIME Content", RFC
2912, September 2000.
Klyne Expires March 28, 2002 [Page 8]
Internet-Draft Message header registration Sep 2001
[23] Chandhok, R. and G. Wenger, "List-Id: A Structured Field and
Namespace for the Identification of Mailing Lists", RFC 2919,
April 2001.
[24] Palme, J., "Common Internet Message Header Fields", Internet
draft draft-palme-mailext-headers-05, May 2001,
<http://search.ietf.org/internet-drafts/draft-palme-mailext-
headers-05.txt>.
[25] Bernstein, D., "Internet mail field name index",
<http://cr.yp.to/immhf/index.html>.
[26] "Mail address for submission of header registration template",
<mailto:[[[ietf-message-headers]]]@iana.org>.
[27] "IANA list of registered message headers",
<http://www.iana.org/[[[ToBeDefined]]]>.
Author's Address
Graham Klyne
MIMEsweeper Group
1310 Waterside
Arlington Business Park
Theale, Reading RG7 4SA
UK
Phone: +44 118 903 8000
Fax: +44 118 903 9000
EMail: Graham.Klyne@MIMEsweeper.com
Appendix A. Revision history
(This section to be removed on final publication)
A.1 draft-klyne-msghdr-registry-00
00a 27-Sep-2001: document initially created.
Appendix B. Todo
(This section to be removed on final publication)
o Finalize choice of RFC 2434 assignment policy. See section
Section 2.1.
Klyne Expires March 28, 2002 [Page 9]
Internet-Draft Message header registration Sep 2001
o Finalize email address for sumbission of registration templates.
o Finalize web address for registry.
Klyne Expires March 28, 2002 [Page 10]
Internet-Draft Message header registration Sep 2001
Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Klyne Expires March 28, 2002 [Page 11]
