Sieve working group R. George
Internet-Draft B. Leiba
Intended status: Standards Track Huawei Technologies
Expires: May 27, 2011 November 23, 2010
Sieve Vacation Extension: "Seconds" parameter
draft-ietf-sieve-vacation-seconds-03
Abstract
This document describes a further extension to the Sieve Vacation
extension, allowing multiple auto-replies to the same sender in a
single day by adding a ":seconds" parameter.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology Used in This Document . . . . . . . . . . . . . . 3
2. The ':seconds' Parameter . . . . . . . . . . . . . . . . . . 3
3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5.1. Registration of Sieve Extension . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
The Sieve [RFC5228] Vacation extension [RFC5230] defines a mechanism
to generate automatic replies to incoming email messages. Through
the ":days" parameter, it limits the number of auto-replies to the
same sender to one per [n] days, for a specified number of days. But
there are cases when one needs more granularity, if one would like to
generate "vacation" replies more frequently.
This extension defines a ":seconds" parameter to provide more
granularity for such situations.
1.1. Terminology Used in This Document
The upper-case 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 [RFC2119].
2. The ':seconds' Parameter
The purpose of the ":seconds" parameter is to specify the minimum
time interval (in seconds) between consecutive auto-replies to a
given sender. The ":seconds" value, if specified, is used instead of
the ":days" value, and works in a similar way (see the Vacation
extension [RFC5230] for details). Only one of ":days" and ":seconds"
is allowed -- use of both parameters in the same vacation action MUST
result in a Sieve processing error.
The capability string associated with this extension is "vacation-
seconds". Note that "vacation-seconds" implies "vacation", and a
script with "vacation-seconds" in a "require" list can omit
"vacation" from that list.
The time value is specified in seconds, and MUST be greater than or
equal to 0 and less than 2**31. All valid values MUST be accepted
without error, but sites MAY define a minimum value to actually be
used if a smaller value is specified, and/or a maximum value to be
used if a larger value is specified. If a site imposes a maximum
value, that value MUST be at least 86400 (one day).
If ":seconds 0" is specified and used, it means that all auto-replies
are sent, and no attempt is made to suppress consecutive replies.
This differs from the base vacation specification, which does not
allow a time period of zero (":days 0" is forbidden); the change is
necessary to allow operation of an auto-responder (see
[I-D.ietf-sieve-autoreply], and note especially example 4 in section
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3 of that document).
If ":seconds" and ":days" are both omitted, a site-defined interval
is used (see [RFC5230]).
Usage: vacation [":days" number | ":seconds" number]
[":subject" string]
[":from" string]
[":addresses" string-list]
[":mime"]
[":handle" string]
<reason: string>
3. Examples
This example will automatically reply to senders with a message that
the recipient is in a meeting. Multiple replies to the same sender
will only be sent every half hour (1800 seconds).
require ["vacation-seconds"];
vacation :addresses ["tjs@example.edu", "ts4z@landru.example.edu"]
:seconds 1800
"I am in a meeting, and do not have access to email.";
This example is used to send an acknowledgment to every message
received. A :seconds value of zero is used to reply to every
message, with no removal of duplicates to the same sender. This
requires that the Sieve engine allow an interval of zero; if it does
not, and it imposes a minimum value, not every message will receive
an auto-reply.
require ["vacation-seconds"];
vacation :handle "auto-resp" :seconds 0
"Your request has been received. A service
representative will contact you as soon as
possible, usually within one business day.";
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4. Security Considerations
Security considerations for the Sieve Vacation extension [RFC5230]
apply equally here. In addition, implementations SHOULD consider the
number of auto-replies that might be generated by allowing small
values of ":seconds" (including 0), and MAY impose additional limits
on that number. See the Security Considerations section of RFC 3834
[RFC3834] for a fuller discussion.
5. IANA Considerations
5.1. Registration of Sieve Extension
To: iana@iana.org
Subject: Registration of new Sieve extension
Capability name: vacation-seconds
Description: adds the ":seconds" parameter to the Sieve Vacation
extension. Implementations that support this MUST also support
"vacation".
RFC number: this RFC
Contact address: The Sieve discussion list <sieve@ietf.org>
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3834] Moore, K., "Recommendations for Automatic Responses to
Electronic Mail", RFC 3834, August 2004.
[RFC5228] Guenther, P. and T. Showalter, "Sieve: An Email Filtering
Language", RFC 5228, January 2008.
[RFC5230] Showalter, T. and N. Freed, "Sieve Email Filtering:
Vacation Extension", RFC 5230, January 2008.
6.2. Informative References
[I-D.ietf-sieve-autoreply]
George, R., Leiba, B., and A. Melnikov, "Sieve Email
Filtering: Use of Presence Information with Auto Responder
functionality", draft-ietf-sieve-autoreply-02 (work in
progress), October 2010.
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Authors' Addresses
Robins George
Huawei Technologies
Bangalore, Karnataka 560071
India
Phone: +91-080-41117676
Email: robinsgv@gmail.com
Barry Leiba
Huawei Technologies
Phone: +1 646 827 0648
Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/
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