Internet Draft K. Murchison
Document: draft-murchison-sieve-subaddress-06.txt Oceana Matrix Ltd.
Expires October 4, 2003 30 March 2003
Sieve -- Subaddress Extension
Status of this Memo
This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026.
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/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
Copyright Notice
Copyright (C) The Internet Society 2003. All Rights Reserved.
Abstract
On email systems that allow for "subaddressing" or "detailed
addressing" (eg, "ken+sieve@example.org"), it is sometimes desirable
to make comparisons against these sub-parts of addresses. This draft
defines an extension to the Sieve mail filtering language that allows
users to compare against the user and detail parts of an address.
Expires October 4, 2003 Murchison [Page 1]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
Table of Contents
Status of this Memo . . . . . . . . . . . . . . . . . . . . . . . . 1
Copyright Notice . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
0. Meta-information on this draft . . . . . . . . . . . . . . . 3
0.1. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 3
0.2. Change History . . . . . . . . . . . . . . . . . . . . . . . 3
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Capability Identifier . . . . . . . . . . . . . . . . . . . . 4
3. Subaddress Comparisons . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Normative References . . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
8. Author's Address . . . . . . . . . . . . . . . . . . . . . . 7
9. Intellectual Property Considerations . . . . . . . . . . . . 7
10. Full Copyright Statement . . . . . . . . . . . . . . . . . . 8
Expires October 4, 2003 Murchison [Page 2]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
0. Meta-information on this draft
This information is intended to facilitate discussion. It will be
removed when this document leaves the Internet-Draft stage.
0.1. Discussion
This draft is intended to be an extension to the Sieve mail filtering
language, available from the RFC repository as
<ftp://ftp.ietf.org/rfc/rfc3028.txt>.
This draft and the Sieve language itself are being discussed on the
MTA Filters mailing list at <ietf-mta-filters@imc.org>. Subscription
requests can be sent to <ietf-mta-filters-request@imc.org> (send an
email message with the word "subscribe" in the body). More
information on the mailing list along with a WWW archive of back
messages is available at <http://www.imc.org/ietf-mta-filters/>.
0.2. Change History
Since -05: Add IANA considerations, conform to ID Nits.
1. Introduction
Subaddressing is the practice of appending some "detail" information
to the local-part of an [IMAIL] address to indicate that the message
should be delivered to the set of messages specified by the "detail"
information. The "detail" information is prefixed with a special
"separator character" (typically "+") which forms the boundary
between the "user" (original local-part) and the "detail" sub-parts
of the address, much like the "@" character forms the boundary
between the local-part and domain.
Typical uses of subaddressing might be:
- A message addressed to "ken+sieve@example.org" is delivered into a
mailbox called "sieve" belonging to the user "ken".
- A message addressed to "5551212#123@example.org" is delivered to
the voice mailbox number "123" at phone number "5551212".
Expires October 4, 2003 Murchison [Page 3]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
This document describes an extension to the Sieve language defined by
[SIEVE] for comparing against the "user" and "detail" sub-parts of an
address.
Conventions for notations are as in [SIEVE] section 1.1, including
use of [KEYWORDS].
2. Capability Identifier
The capability string associated with the extension defined in this
document is "subaddress".
3. Subaddress Comparisons
Commands that act exclusively on addresses may take the optional
tagged arguments ":user" and ":detail" to specify what sub-part of
the local-part of the address will be acted upon.
NOTE: In most cases, the envelope "to" address is the prefered
address to examine for subaddress information when the desire is to
sort messages based on how they were addressed so as to get to a
specific recipient. The envelope address is, after all, the reason a
given message is being processed by a given sieve script for a given
user. This is particularly true when mailing lists, aliases, and
"virtual domains" are involved since the envelope may be the only
source of detail information for the specific recipient.
The ":user" argument specifies that sub-part of the local-part which
lies to the left of the separator character (eg, "ken" in
"ken+sieve@example.org"). If no separator character exists, then
":user" specifies the entire left-side of the address (equivalent to
":localpart").
The ":detail" argument specifies that sub-part of the local-part
which lies to the right of the separator character (eg, "sieve" in
"ken+sieve@example.org"). If no separator characater exists, the the
test evaluates to false. If nothing lies to the right of the
separator character, then ":detail" ":is" the null key ("").
Otherwise, the ":detail" sub-part contains the null key.
Implementations MUST make sure that the separator character matches
that which is used and/or allowed by the encompassing mail system,
otherwise unexpected results might occur. Implementations SHOULD
allow the separator character to be configurable so that they may be
used with a variety of mail systems.
Expires October 4, 2003 Murchison [Page 4]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
The ":user" and ":detail" address parts are subject to the same rules
and restrictions as the standard address parts defined in [SIEVE].
For convenience, the "ADDRESS-PART" syntax element defined in [SIEVE]
is augmented here as follows:
ADDRESS-PART =/ ":user" / ":detail"
A diagram showing the ADDRESS-PARTs of a email address utilizing a
separator character of '+' is shown below:
:user "+" :detail "@" :domain
`-----------------'
:local-part
Example:
require "subaddress";
# File mailing list messages (subscribed as "ken+mta-filters").
if envelope :detail "to" "mta-filters" {
fileinto "inbox.ietf-mta-filters";
}
# If a message is not to me (ignoring +detail), junk it.
if not allof (address :user ["to", "cc", "bcc"] "ken",
address :domain ["to", "cc", "bcc"] "example.org") {
discard;
}
# Redirect all mail sent to +foo.
if envelope :detail ["to", "cc", "bcc"] "foo" {
redirect "ken@example.edu";
}
4. Security Considerations
Security considerations are discussed in [SIEVE]. It is believed
that this extension does not introduce any additional security
concerns.
Expires October 4, 2003 Murchison [Page 5]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
5. IANA Considerations
The following template specifies the IANA registration of the Sieve
extension specified in this document:
To: iana@iana.org
Subject: Registration of new Sieve extension
Capability name: subaddress
Capability keyword: subaddress
Capability arguments: N/A
Standards Track/IESG-approved experimental RFC number: this RFC
Person and email address to contact for further information:
Kenneth Murchison
ken@oceana.com
This information should be added to the list of sieve extensions
given on http://www.iana.org/assignments/sieve-extensions.
6. Normative References
[IMAIL] Resnick, P., Ed., "Internet Message Format", QUALCOMM
Incorporated, RFC 2822, April 2001.
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", Harvard University, RFC 2119, March 1997.
[SIEVE] Showalter, T., "Sieve: A Mail Filtering Language", Mira¡
point, Inc., RFC 3028, January 2001.
7. Acknowledgments
Thanks to Tim Showalter, Alexey Melnikov, Michael Salmon, Randall
Gellens, Philip Guenther and Jutta Degener for their help with this
document.
Expires October 4, 2003 Murchison [Page 6]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
8. Author's Address
Kenneth Murchison
Oceana Matrix Ltd.
21 Princeton Place
Orchard Park, NY 14127
EMail: ken@oceana.com
9. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any
intellectual property 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; neither does it represent that it has
made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication 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 implementors or users of this specification can be obtained
from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Expires October 4, 2003 Murchison [Page 7]
Internet Draft Sieve -- Subaddress Extension March 30, 2003
10. Full Copyright Statement
Copyright (C) The Internet Society 2003. All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implmentation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS 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.
Expires October 4, 2003 Murchison [Page 8]