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Internet Engineering Task Force (IETF)                         R. GeorgeRequest for Comments: 6131                                      B. LeibaCategory: Standards Track                            Huawei TechnologiesISSN: 2070-1721                                                July 2011Sieve Vacation Extension: "Seconds" ParameterAbstract   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   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc6131.Copyright Notice   Copyright (c) 2011 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://trustee.ietf.org/license-info) in effect on the date of   publication of this document.  Please review these documents   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.George & Leiba               Standards Track                    [Page 1]

RFC 6131            Sieve Vacation: Seconds Parameter          July 2011Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .21.1.  Terminology Used in This Document . . . . . . . . . . . . .22.  The ':seconds' Parameter  . . . . . . . . . . . . . . . . . . .23.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . .44.  Security Considerations . . . . . . . . . . . . . . . . . . . .45.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . .45.1.  Registration of Sieve Extension . . . . . . . . . . . . . .46.  References  . . . . . . . . . . . . . . . . . . . . . . . . . .56.1.  Normative References  . . . . . . . . . . . . . . . . . . .56.2.  Informative References  . . . . . . . . . . . . . . . . . .51.  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 inRFC2119 [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" or ":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.George & Leiba               Standards Track                    [Page 2]

RFC 6131            Sieve Vacation: Seconds Parameter          July 2011   The time value is specified in seconds, and MUST be greater than or   equal to 0 and less than 2**31.  All valid values, from 0 to 2**31,   MUST be accepted without error.  Sites MAY define a minimum effective   value and/or a maximum effective value.  If a site chooses to do   that:   1.  Call the value specified "v(spec)".   2.  Call the minimum effective value "v(min)".   3.  Call the maximum effective value "v(max)".   4.  Call the actual effective value used by the processor "v(eff)".   5.  The following apply for determining v(eff):       *  If 0 <= v(spec) < v(min), then v(eff) = v(min).       *  If v(min) <= v(spec) <= v(max), then v(eff) = v(spec).       *  If v(max) < v(spec) <= 2**31, then v(eff) = v(max).   If a site imposes a maximum effective 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 [RFC6133], and   note especially example 4 insection 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>George & Leiba               Standards Track                    [Page 3]

RFC 6131            Sieve Vacation: Seconds Parameter          July 20113.  Examples   The following 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.";   The following 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.";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 ofRFC 3834   [RFC3834] for a fuller discussion.5.  IANA Considerations5.1.  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:RFC 6131   Contact address:  The Sieve discussion list <sieve@ietf.org>George & Leiba               Standards Track                    [Page 4]

RFC 6131            Sieve Vacation: Seconds Parameter          July 20116.  References6.1.  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   [RFC6133]  George, R., Leiba, B., and A. Melnikov, "Sieve Email              Filtering: Use of Presence Information with Auto-Responder              Functionality",RFC 6133, July 2011.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/George & Leiba               Standards Track                    [Page 5]