Update to Internet Message Format to Allow Group Syntax in the "From:" and "Sender:" Header Fields
RFC 6854
Document | Type |
RFC - Proposed Standard
(March 2013; No errata)
Updates RFC 5322
Was draft-leiba-5322upd-from-group (individual in app area)
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Author | Barry Leiba | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6854 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Pete Resnick | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) B. Leiba Request for Comments: 6854 Huawei Technologies Updates: 5322 March 2013 Category: Standards Track ISSN: 2070-1721 Update to Internet Message Format to Allow Group Syntax in the "From:" and "Sender:" Header Fields Abstract The Internet Message Format (RFC 5322) allows "group" syntax in some email header fields, such as "To:" and "CC:", but not in "From:" or "Sender:". This document updates RFC 5322 to relax that restriction, allowing group syntax in those latter fields, as well as in "Resent-From:" and "Resent-Sender:", in certain situations. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6854. 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 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Leiba Standards Track [Page 1] RFC 6854 Group Syntax in "From:" and "Sender:" March 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3 1.1.1. Requirements Notation . . . . . . . . . . . . . . . . . 3 1.1.2. Syntactic Notation . . . . . . . . . . . . . . . . . . 3 2. Allowing Group Syntax in "From:" and "Sender:" . . . . . . . . 3 2.1. Replacement of RFC 5322, Section 3.6.2. Originator Fields . 4 2.2. Update to RFC 5322, Section 3.6.6. Resent Fields . . . . . 5 3. Applicability Statement . . . . . . . . . . . . . . . . . . . . 6 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . . 9 1. Introduction The Internet Message Format, as far back as RFC 822 [RFC0822], has always required a usable address to appear in the "From:" header field of messages in order to allow replies to be sent. To this end, the syntax of messages, up to and including the current specification [RFC5322], has required the use of the mailbox address form in the originator ("From:" and "Sender:") fields of messages and has specifically forbidden the use of the group address form, which permits an empty list of addresses (that is, an address list with no address included that might be used for a reply). However, the use cases for the "From:" field have evolved. There are numerous instances of automated systems that wish to send email but cannot handle replies, and a "From:" field with no usable addresses would be extremely useful for that purpose. More recently, work with internationalized email addresses [RFC6530] creates a real need to take a message with an internationalized email address and hand it to an older client that would have no ability to reply to such an address but might still wish to display the contents of the message. The group construct provides an existing syntax for unusable addresses (using the empty list of addresses) and also allows for a text label that describes the originator. For example: From: Automated System:; A review of many current email programs finds that all reviewed clients will properly display a message with group syntax in the "From:" field. At worst, such programs generate an error message when an attempt is made to reply to such a message. No other interoperability problems have been discovered. Leiba Standards Track [Page 2]Show full document text