SMTP Extension for Internationalized Email Addresses
RFC 5336
Document | Type |
RFC - Experimental
(September 2008; Errata)
Obsoleted by RFC 6531
Was draft-ietf-eai-smtpext (eai WG)
|
|
---|---|---|---|
Authors | Jiankang Yao , Wei MAO | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5336 (Experimental) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Chris Newman | ||
Send notices to | (None) |
Network Working Group J. Yao, Ed. Request for Comments: 5336 W. Mao, Ed. Updates: 2821, 2822, 4952 CNNIC Category: Experimental September 2008 SMTP Extension for Internationalized Email Addresses Status of This Memo This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited. Abstract This document specifies an SMTP extension for transport and delivery of email messages with internationalized email addresses or header information. Communication with systems that do not implement this specification is specified in another document. This document updates some syntaxes and rules defined in RFC 2821 and RFC 2822, and has some material updating RFC 4952. Yao & Mao Experimental [Page 1] RFC 5336 EAI SMTP Extension September 2008 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Role of This Specification . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Overview of Operation . . . . . . . . . . . . . . . . . . . . 4 3. Mail Transport-Level Protocol . . . . . . . . . . . . . . . . 4 3.1. Framework for the Internationalization Extension . . . . . 4 3.2. The UTF8SMTP Extension . . . . . . . . . . . . . . . . . . 5 3.3. Extended Mailbox Address Syntax . . . . . . . . . . . . . 7 3.4. The ALT-ADDRESS Parameter . . . . . . . . . . . . . . . . 9 3.5. ALT-ADDRESS Parameter Usage and Response Codes . . . . . . 10 3.6. Body Parts and SMTP Extensions . . . . . . . . . . . . . . 11 3.7. Additional ESMTP Changes and Clarifications . . . . . . . 11 3.7.1. The Initial SMTP Exchange . . . . . . . . . . . . . . 12 3.7.2. Mail eXchangers . . . . . . . . . . . . . . . . . . . 12 3.7.3. Trace Information . . . . . . . . . . . . . . . . . . 12 3.7.4. UTF-8 Strings in Replies . . . . . . . . . . . . . . . 13 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.1. Normative References . . . . . . . . . . . . . . . . . . . 18 7.2. Informative References . . . . . . . . . . . . . . . . . . 19 Appendix A. Material Updating RFC 4952 . . . . . . . . . . . . . 20 A.1. Conventional Message and Internationalized Message . . . . 20 A.2. LMTP . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 A.3. SMTP Service Extension for DSNs . . . . . . . . . . . . . 20 A.4. Implementation Advice . . . . . . . . . . . . . . . . . . 20 A.5. Applicability of SMTP Extension to Additional Uses . . . . 21 Yao & Mao Experimental [Page 2] RFC 5336 EAI SMTP Extension September 2008 1. Introduction An internationalized email address includes two parts, the local part and the domain part. The ways email addresses are used by protocols are different from the ways domain names are used. The most critical difference is that emails are delivered through a chain of clients and servers, while domain names are resolved by name servers looking up those names in their own tables. In addition to this, the Simple Mail Transfer Protocol [RFC2821] provides a negotiation mechanism about service extension with which clients can discover server capabilities and make decisions for further processing. An extended overview of the extension model for internationalized addresses and headers appears in [RFC4952], referred to as "the framework document" or just as "Framework" elsewhere in this specification. This document specifies an SMTP extension to permit internationalized email addresses in envelopes, and UNICODE characters (encoded in UTF-8) [RFC3629] in headers. 1.1. Role of This Specification The framework document specifies the requirements for, and describes components of, full internationalization of electronic mail. A thorough understanding of the information in that document and in the base Internet email specifications [RFC2821] [RFC2822] is necessary to understand and implement this specification. This document specifies an element of the email internationalization work, specifically the definition of an SMTP extension [RFC2821] for internationalized email address transport delivery.Show full document text