INTERNET-DRAFT                                           Jayantheesh S B 
Intended status: Informational                                   Samsung
Expires: April 2015                                 Narendra Singh Bisht
                                                                 Samsung
                                                        October 13, 2014

             SMTP Service Extension for command SENTCOPY 
                draft-jayantheesh-smtp-sentcopy-00

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Abstract

This memo defines an extension to the SMTP service whereby a server can
indicate the extent of its ability to copy the emails which are sent by
the user to IMAP Sent folders automatically.

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 RFC 2119.
Example lines prefaced by "C:" are sent by the client and ones prefaced
by "S:" by the server. The five characters [...] means that something
has been elided.

Overview

As of now whenever an email client sends an email, it has to send it to
the SMTP server as well as upload it to the Sent mailbox of IMAP server.
Some of the SMTP servers have the ability to copy the email sent by the
user to IMAP Sent folder also, thus avoiding unnecessary network
transaction. IMAP client cannot know this SMTP server capability unless
it is published as part of EHLO response.

SMTP server MAY have proprietary way of copying the mails or it MAY
follow any standard mechanism mentioned to copy the mails to IMAP Sent
folder. In both the cases, IMAP client SHOULD be notified to avoid
unnecessary copy of emails. 

By this way, mail client SHALL easily identify the capabilities of the
SMTP server and avoid copying of emails twice.

The SENTCOPY Service Extension

The Command SENTCOPY extension is defined as follows:
 (1)   The name of the SMTP service extension is Sentcopy;
 (2)   The EHLO keyword value associated with the extension is
       SENTCOPY;
 (3)   No parameter is used with the SENTCOPY EHLO keyword;

When a client wishes to send email, it first issues the EHLO command to
the SMTP server. If the SMTP server responds with code 250 to the EHLO
command and the response includes the EHLO keyword value SENTCOPY, then
the SMTP server has indicated that it has the ability to perform the
copy of emails to IMAP Sent folder. By looking at the keyword, client
can avoid doing the copy operation to IMAP folder.

Example of SENTCOPY supported SMTP EHLO response

 C: EHLO example.com
 S: 250-example.com says hello
 S: 250-SIZE 35882577
 S: 250-8BITMIME
 S: 250-PIPELINING
 S: 250-CHUNKING
 S: 250-SENTCOPY
 S: ... 

Especially in the mobile device environment, copying the same email
twice consumes more device resources like device battery power and
mobile data. This SHALL be avoided by publishing the SMTP capability 
"SENTCOPY" to the email client. Irrespective of the server side
implementation, email client shall easily identify and ignore the
duplicate copy of emails. 

Security Consideration

This document does not add any new security considerations to SMTP.

IANA Considerations

This document has no actions for IANA.

Normative References

http://en.wikipedia.org/wiki/Internet_Message_Access_Protocol

http://www.ietf.org/rfc/rfc5321.txt

Author's Address

Jayantheesh S B
Samsung Telecommunications America,
685 US Highway 202/206,
Bridgewater, NJ 08807.
USA
Email: jayantheesh.sb@gmail.com

Narendra Singh Bisht
Samsung Telecommunications America,
685 US Highway 202/206,
Bridgewater, NJ 08807.
USA
Email: narendrasingh.bisht@gmail.com