Sieve Vacation Extension: "Seconds" parameter
draft-george-sieve-vacation-time-01

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.

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Table of Contents

• 1. Introduction
• 1.1. Terminology Used in This Document
• 2. 'Seconds' Parameter
• 3. Examples
• 4. Security Considerations
• 5. IANA Considerations
• 5.1. Registration of Sieve Extension
• 6. References
• Authors' Addresses

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 for shorter-term situations ("in a meeting", for example, or "out to lunch").

This extension defines a ":seconds" parameter to provide more granularity for such situations.

1.1. Terminology 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 [RFC2119].

2. '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 -- both MAY NOT be specified (it is a compile-time error to do so).

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 MAY 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. If 0 is specified and used, it means that all auto-replies are sent, and no attempt is made to suppress consecutive replies.

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

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 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 :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.";

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.

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).

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 <ietf-mta-filters@imc.org>

6. References

Authors' Addresses