Internet DRAFT - draft-melnikov-email-user-agent
draft-melnikov-email-user-agent
Network Working Group A. Melnikov
Internet-Draft Isode Ltd
Intended status: Informational October 21, 2013
Expires: April 24, 2014
User-Agent and X-Mailer Header Field registration for Email
draft-melnikov-email-user-agent-00
Abstract
This memo registers User-Agent and X-Mailer header fields in the
Permanent Message Header Field Names IANA registry.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 24, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. User-Agent header field . . . . . . . . . . . . . . . . . . . 2
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
6.1. Normative References . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . 4
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 4
Appendix B. Use of User-Agent and X-Mailer by existing email
agents . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
User-Agent and X-Mailer are common Email header fields for
identifying any software (and its components) that generates email
messages. They are used for helping in debugging email generation
and processing errors, for tracking use of different email clients.
The User-Agent header field is already registered for use in HTTP
[RFC2616] and NetNews [RFC5536]. This document registers it for use
in email.
2. Conventions Used in This Document
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 [RFC2119] when they
appear in ALL CAPS. These words also appear in this document in
lower case as plain English words, absent their normative meanings.
The formal syntax use the Augmented Backus-Naur Form (ABNF) [RFC5234]
notation including the core rules defined in Appendix B of RFC 5234
[RFC5234].
3. User-Agent header field
The User-Agent header field contains information about the user agent
(typically a Mail User Agent) generating the email message, for
statistical purposes and tracing of standards violations to specific
software in need of correction.
ABNF for this header field is defined as follows:
user-agent = "User-Agent:" 1*product [CFWS] CRLF
product = [CFWS] token [ [CFWS] "/" product-version ]
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product-version = [CFWS] token
CFWS = <Defined in RFC 5322>
token = <Defined in RFC 2045 Section 5.1>
This header field MAY contain multiple <product> tokens identifying
the user agent and any subproducts that form a significant part of
it, listed in order of their significance for identifying the
application.
NOTE: Many popular email clients and agents are using X-Mailer header
field instead of the User-Agent header field.
NOTE: [RFC2616] describes a similar facility for the HTTP protocol.
The Email format differs in that "{" and "}" are allowed in tokens
(<product> and <product-version>) and comments are permitted wherever
white space is allowed.
4. IANA Considerations
IANA is requested to add the following list of header field names to
the "Permanent Message Header Field Names" registry (in http://
www.iana.org/assignments/message-headers/perm-headers.html):
Header field: User-Agent
Applicable protocol: mail
Status: standard
Author/change controller: IESG (iesg@ietf.org) on behalf of the IETF
Specification document(s): [[this document]]
Related information: [RFC2616] (Section 14.43)
Header field: X-Mailer
Applicable protocol: mail
Status: standard
Author/change controller: IESG (iesg@ietf.org) on behalf of the IETF
Specification document(s): [[this document]]
Related information: [RFC2616] (Section 14.43)
5. Security Considerations
TBD
6. References
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6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
6.2. Informative References
[RFC5536] Murchison, K., Lindsey, C., and D. Kohn, "Netnews Article
Format", RFC 5536, November 2009.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
Appendix A. Acknowledgements
This document copies lots of text from [RFC5536], so the author of
this document would like to acknowledge contributions made by the
authors of that RFC.
Appendix B. Use of User-Agent and X-Mailer by existing email agents
+-----------------------------+-------------------------------------+
| Name of an Email Agent | Header Field used for |
| | identification |
+-----------------------------+-------------------------------------+
| Thunderbird | User-Agent |
| | |
| Trojita | User-Agent |
| | |
| Mutt | User-Agent |
| | |
| Facebook | X-Mailer |
| | |
| Yahoo! Mail | X-Mailer |
| | |
| Inky | X-Mailer |
| | |
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| Apple iPad Mail | X-Mailer |
| | |
| git | X-Mailer |
| | |
| Microsoft Outlook | X-Mailer |
| | |
| Microsoft Windows Live Mail | X-Mailer |
+-----------------------------+-------------------------------------+
Author's Address
Alexey Melnikov
Isode Ltd
5 Castle Business Village
36 Station Road
Hampton, Middlesex TW12 2BX
UK
EMail: Alexey.Melnikov@isode.com
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