Recommendations for Automatic Responses to Electronic Mail
RFC 3834

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Network Working Group                                           K. Moore
Request for Comments: 3834                       University of Tennessee
Category: Standards Track                                    August 2004

       Recommendations for Automatic Responses to Electronic Mail

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This memo makes recommendations for software that automatically
   responds to incoming electronic mail messages, including "out of the
   office" or "vacation" response generators, mail filtering software,
   email-based information services, and other automatic responders.
   The purpose of these recommendations is to discourage undesirable
   behavior which is caused or aggravated by such software, to encourage
   uniform behavior (where appropriate) among automatic mail responders,
   and to clear up some sources of confusion among implementors of
   automatic email responders.

1.  Introduction

   Many programs which automatically respond to email are currently in
   use.  Although these programs vary widely in their function, several
   problems with this class of programs have been observed, including:
   significant numbers of useless or unwanted response and responses
   sent to inappropriate addresses, and occasional incidences of mail
   loops or "sorcerer's apprentice" mode.  This memo recommends behavior
   for programs that automatically respond to electronic mail in order
   to reduce the number of problems caused by such programs.

   (Note: the term "sorcerer's apprentice mode" is defined as a bug in a
   protocol where, under some circumstances, the receipt of a message
   causes multiple messages to be sent, each of which, when received,
   triggers the same bug.) (From [I1.JARGON])

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RFC 3834               Automatic E-Mail Responses            August 2004

   This document is limited in scope to Internet electronic mail
   messages and many of its recommendations are specifically tailored
   for the protocol elements and data models used in Internet electronic
   mail messages and SMTP transport envelopes.  Use of these
   recommendations in other messaging contexts such as instant
   messaging, SMS, or Usenet has not been considered, and is outside of
   the scope of this document.

1.1.  Types of automatic responses

   There are several different types of automatic responses.  At least
   two types of automatic responses have been defined in IETF standards
   - Delivery Status Notifications [I2.RFC3464] which are intended to
   report the status of a message delivery by the message transport
   system, and Message Disposition Notifications [I3.RFC3798] which are
   intended to report of the disposition of a message after it reaches a
   recipient's mailbox.  These responses are defined elsewhere and are
   generally not within the purview of this document, except that this
   document recommends specific cases where they should or should not be
   used.

   Other types of automatic response in common use include:

   -  "Out of office" or "vacation" notices, which are intended to
      inform the sender of a message that the message is unlikely to be
      read, or acted on, for some amount of time,

   -  "Change of address" notices, intended to inform the sender of a
      message that the recipient address he used is obsolete and that a
      different address should be used instead (whether or not the
      subject message was forwarded to the current address),

   -  "Challenges", which require the sender of a message to demonstrate
      some measure of intelligence and/or willingness to agree to some
      conditions before the subject message will be delivered to the
      recipient (often to minimize the effect of "spam" or viruses on
      the recipient),

   -  Email-based information services, which accept requests
      (presumably from humans) via email, provide some service, and
      issue responses via email also.  (Mailing lists which accept
      subscription requests via email fall into this category),

   -  Information services similar to those mentioned above except that
      they are intended to accept messages from other programs, and

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RFC 3834               Automatic E-Mail Responses            August 2004

   -  Various kinds of mail filters (including "virus scanners") which
      act on behalf of a recipient to alter the content of messages
      before forwarding them to that recipient, and issue responses in