Displaying Downgraded Messages for Email Address Internationalization
RFC 5825
Document | Type |
RFC - Experimental
(April 2010; No errata)
Obsoleted by RFC 6530
|
|
---|---|---|---|
Authors | Barry Leiba , Kazunori Fujiwara | ||
Last updated | 2015-10-14 | ||
Replaces | draft-fujiwara-eai-downgraded-display | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5825 (Experimental) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Alexey Melnikov | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) K. Fujiwara Request for Comments: 5825 JPRS Category: Experimental B. Leiba ISSN: 2070-1721 Huawei Technologies April 2010 Displaying Downgraded Messages for Email Address Internationalization Abstract This document describes a method for displaying downgraded messages that originally contained internationalized email addresses or internationalized header fields. Status of This Memo This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation. This document defines an Experimental Protocol for the Internet community. 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see 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/rfc5825. Copyright Notice Copyright (c) 2010 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. Fujiwara & Leiba Experimental [Page 1] RFC 5825 Displaying Downgraded Messages April 2010 Table of Contents 1. Introduction ....................................................2 2. Terminology .....................................................2 3. Converting Downgraded Message Headers for Display ...............3 3.1. Considerations .............................................3 3.2. The Process ................................................3 3.2.1. No Reconstruction of the Envelope Information Preservation ............................4 3.2.2. Reconstructing the Address Header Fields' Preservation Header .................................4 3.2.3. The Unknown Header Fields' Preservation Header Fields .......................................5 4. Security Considerations .........................................6 5. Acknowledgements ................................................6 6. References ......................................................6 6.1. Normative References .......................................6 6.2. Informative References .....................................7 Appendix A. Examples ..............................................8 A.1. Displaying Example ........................................11 1. Introduction The Email Address Internationalization (UTF8SMTP) extension document set [RFC4952] [RFC5336] [RFC5335] [RFC5337] expands Email address structure, syntax, and email header format. To avoid rejection of internationalized email messages, the downgrading mechanism [RFC5504] converts an internationalized message to a traditional email message when a server in the delivery path does not support the UTF8SMTP extension. The downgraded message is a traditional email message, except the message has "Downgraded-" header fields. A perfect reverse-function of the downgrading does not exist because the encoding defined in [RFC2047] is not exactly reversible and "Received" header field downgrading may remove FOR clause information. The restoration of the downgrading should be done once at the final destination of the downgraded message such as Mail User Agents (MUAs) or IMAP servers. This document describes the restoration methods for displaying downgraded messages in MUAs. 2. Terminology 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 [RFC2119]. Fujiwara & Leiba Experimental [Page 2] RFC 5825 Displaying Downgraded Messages April 2010 Specialized terms used in this specification are defined in the EAIShow full document text