SMTP Service Extension for 8-bit MIME Transport
RFC 6152
Document | Type |
RFC - Internet Standard
(March 2011; Errata)
Obsoletes RFC 1652
Also known as STD 71
|
|
---|---|---|---|
Authors | Dave Crocker , John Klensin , Marshall Rose , Ned Freed | ||
Last updated | 2019-03-06 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6152 (Internet Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Alexey Melnikov | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) J. Klensin Request for Comments: 6152 STD: 71 N. Freed Obsoletes: 1652 Oracle Category: Standards Track M. Rose ISSN: 2070-1721 Dover Beach Consulting, Inc. D. Crocker, Ed. Brandenburg InternetWorking March 2011 SMTP Service Extension for 8-bit MIME Transport Abstract This memo defines an extension to the SMTP service whereby an SMTP content body consisting of text containing octets outside of the US-ASCII octet range (hex 00-7F) may be relayed using SMTP. 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/rfc6152. Copyright Notice Copyright (c) 2011 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. Klensin, et al. Standards Track [Page 1] RFC 6152 SMTP Extension for 8-bit MIME March 2011 1. Introduction Although SMTP is widely and robustly deployed, various extensions have been requested by parts of the Internet community. In particular, a significant portion of the Internet community wishes to exchange messages in which the content body consists of a MIME message [RFC2045][RFC2046][RFC5322] containing arbitrary octet- aligned material. This memo uses the mechanism described in the SMTP specification [RFC5321] to define an extension to the SMTP service whereby such contents may be exchanged. Note that this extension does NOT eliminate the possibility of an SMTP server limiting line length; servers are free to implement this extension but nevertheless set a line length limit no lower than 1000 octets. Given that this restriction still applies, this extension does NOT provide a means for transferring unencoded binary via SMTP. 2. Framework for the 8-bit MIME Transport Extension The 8-bit MIME transport extension is laid out as follows: 1. the name of the SMTP service extension defined here is 8bit-MIMEtransport; 2. the EHLO keyword value associated with the extension is 8BITMIME; 3. no parameter is used with the 8BITMIME EHLO keyword; 4. one optional parameter using the keyword BODY is added to the MAIL command. The value associated with this parameter is a keyword indicating whether a 7-bit message (in strict compliance with [RFC5321]) or a MIME message (in strict compliance with [RFC2046] and [RFC2045]) with arbitrary octet content is being sent. The syntax of the value is as follows, using the ABNF notation of [RFC5234]: body-value = "7BIT" / "8BITMIME" 5. no additional SMTP verbs are defined by this extension; and 6. the next section specifies how support for the extension affects the behavior of a server and client SMTP. 3. The 8bit-MIMEtransport Service Extension When a client SMTP wishes to submit (using the MAIL command) a content body consisting of a MIME message containing arbitrary lines of octet-aligned material, it first issues the EHLO command to the server SMTP. If the server SMTP responds with code 250 to the EHLO Klensin, et al. Standards Track [Page 2] RFC 6152 SMTP Extension for 8-bit MIME March 2011 command, and the response includes the EHLO keyword value 8BITMIME, then the server SMTP is indicating that it supports the extended MAIL command and will accept MIME messages containing arbitrary octet- aligned material. The extended MAIL command is issued by a client SMTP when it wishesShow full document text