Internet DRAFT - draft-arun-ncc-smtp
draft-arun-ncc-smtp
Internet-Draft Ncc in Mail Header Arun Sankar
Hewlett-Packard Company
Expires: October 05, 2005 April 05, 2005
Ncc in Mail Header
draft-arun-ncc-smtp-02.txt
Status of this Memo
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance
with RFC 3668.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved
Abstract
This draft presents a mechanism to simplify one of the cumbersome
aspects of mailing, when one needs to send mails only to a subset of
mail-ids from an alias [ALIAS] . The basic intention is only to minimize
the complication and difficulty of a mail user when a mail needs to be
sent to n - m mail IDs i.e. send it to a group Id of n and exclude m
from the alias [ALIAS] list.
1. Introduction
The current situation is that when a mail is to be sent to an
alias [ALIAS] list, there is no possible way of a negating a set of
mail IDs from that list. The purpose of this draft is a solution
by the addition of another field in the Mail header. The intention
is to achieve this negation of a mail IDs from an alias [ALIAS].
2. Conventions Used in this Document
The key words "REQUIRED", "MUST", "MUST NOT", "SHOULD", "SHOULD
NOT", and "MAY" in this document are to be interpreted as described
in "Key words for use in RFCs to Indicate Requirement Levels"
Arun Sankar Expires October 05 2005 [Page 1]
Internet-Draft Ncc in Mail Header April 05 2005
[KEYWORDS].
3. Requirement
The requirement is to provide the user with a field, using which
mails can be sent to a subset of an alias [ALIAS], i.e. a provision
"not" to deliver the mail to a set of mail IDs from the alias [ALIAS].
4. Header Updations
A new field needs to be added into the SMTP header [RECEIVER FIELDS]
called "Ncc". This would act as a negation to the To, Cc and Bcc
fields and ensure the mail is not sent to the mail ID mentioned
in the "Ncc" field. The Ncc field SHOULD be a part of the mail
header in the implementation. This needs to be a part of the
header as the alias processing could be done in any of the
intermediate relay servers and the "Ncc" field needs to be
available for processing.
5. Format of the Field
The format specification of this field should be treated as
a "Cc" field. This field would be a part of the header and
would be carried forward throughout the mail thread.
6. The SMTP service extension for Ncc
The Ncc option MAY not be implemented in all Mail Servers.
This SHOULD not affect the servers that have implemented Ncc.
The client can figure out if the server has Ncc implemented
using the EHLO command transaction. When the client sends the
EHLO command, the server responds with "NCC".
E.g.
S: 220 test1.example.com ESMTP server ready
C: EHLO test2.example.com
S: 250-test1.example.com
S: 250 NCC
If the server does not respond with an Ncc, the mail SHOULD
not be processed further but a suitable error message like
"NCC" not supported should be sent back to the sender.
6. Processing of the Ncc Field.
The Ncc Field MUST be processed after the alias [ALIAS] has
been expanded and before the creation of the envelope. The
mail IDs in the Ncc field MUST be removed from the To, Cc and
the Bcc fields during its processing. If there is an alias
[ALIAS] in the "Ncc" field, it should be expanded first and
then proceed with the negation of the Mail-Id's. Each recipient
address from "Ncc" header field SHOULD NOT be copied to a RCPT
command. Any empty fields SHOULD then be removed from the
headers. Once this process is completed, the remaining headers
SHOULD be checked to verify that at least one To:, Cc:, or Bcc:
Arun Sankar Expires October 05 2005 [Page 2]
Internet-Draft Ncc in Mail Header April 05 2005
header remains. If none do, then the From: address SHOULD to be
added to the "Rcpt To" command and the mail processing could be
continued. Implimentations SHOULD ensure appropriate error
conditions in case the To:, Cc: and the Bcc: field gets negated
and are nullified. This field MUST be treated similar to the Cc
field with respect to syntax and and processing has to be done
in mail gateways, relays etc. The Ncc field has to be a part of
the mail envelope. Its existence in the envelope is necessary as
the alias expansion can happen in any intermediate server.
7. Example
A needs to send a mail to a group but the intention is not to
send this to D.
From: A From: A
To: B To: B
CC: C,E,F,G,H CC: Team_ABCDEFGH
nCC: D
Subject: TEST Subject: TEST
On the continuation of the thread and D is still not a part of
the list.
From: B From: B
To: A To: A
CC: C,E,F,G,H CC: Team_ABCDEFGH
nCC: D
Subject: TEST Subject: TEST
8. Security Considerations.
The most important Security point that needs to be considered
in this draft is with recpect to a User-Agent that does not
have Ncc implimented. This User-Agent might drop the header
that it does not understand. This could result in the "Ncc"
Header being dropped and even a server that supports the "Ncc"
field would not be able to process the "Ncc" field in the reply.
The other minor problem is when the server does not support
"Ncc", which is solved by the service extention to SMTP.
Appendices
A. References
The following documents contain definitions or specifications that
are necessary to understand this document properly:
[ALIAS] J. Klensin, "Simple Mail Transfer Protocol",
RFC: 2821, April 2001
[RECEIVER FIELDS] Crocker, D., "Standard of the Format of
ARPA Internet Text Messages", RFC 822,
August 1982.
Arun Sankar Expires October 05 2005 [Page 3]
Internet-Draft Ncc in Mail Header April 05 2005
[KEYWORDS] Bradner, S., "Key words for use in RFCs
to Indicate Requirement Levels", BCP 14,
RFC 2119, March 1997.
Author's Address
Arun Sankar
Hewlett-Packard,
29, Cunningham road,
Bangalore,
India 560052
sankar@hp.com
+91-80-205-3107
9. Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology described
in this document or the extent to which any license under such
rights might or might not be available; nor does it represent that
it has made any independent effort to identify any such rights.
Information on the procedures with respect to rights in RFC
documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use
of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Arun Sankar Expires October 05 2005 [Page 4]
