IMAP4 Extension for Returning STATUS Information in Extended LIST
RFC 5819

Document Type RFC - Proposed Standard (March 2010; Errata)
Last updated 2013-03-02
Replaces draft-melnikov-imapext-status-in-list
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IESG IESG state RFC 5819 (Proposed Standard)
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Responsible AD Lisa Dusseault
Send notices to morg-chairs@ietf.org, barryleiba@computer.org, draft-ietf-morg-status-in-list@ietf.org
Internet Engineering Task Force (IETF)                       A. Melnikov
Request for Comments: 5819                                 Isode Limited
Category: Standards Track                                    T. Sirainen
ISSN: 2070-1721                                             Unaffiliated
                                                              March 2010

   IMAP4 Extension for Returning STATUS Information in Extended LIST

Abstract

   Many IMAP clients display information about total number of
   messages / total number of unseen messages in IMAP mailboxes.  In
   order to do that, they are forced to issue a LIST or LSUB command and
   to list all available mailboxes, followed by a STATUS command for
   each mailbox found.  This document provides an extension to LIST
   command that allows the client to request STATUS information for
   mailboxes together with other information typically returned by the
   LIST command.

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 in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5819.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 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.

Melnikov & Sirainen          Standards Track                    [Page 1]
RFC 5819                         TITLE*                       March 2010

Table of Contents

   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................2
   2. STATUS Return Option to LIST Command ............................2
   3. Examples ........................................................3
   4. Formal Syntax ...................................................4
   5. Security Considerations .........................................4
   6. IANA Considerations .............................................4
   7. Acknowledgements ................................................5
   8. Normative References ............................................5

1.  Introduction

   Many IMAP clients display information about the total number of
   messages / total number of unseen messages in IMAP mailboxes.  In
   order to do that, they are forced to issue a LIST or LSUB command and
   to list all available mailboxes, followed by a STATUS command for
   each mailbox found.  This document provides an extension to LIST
   command that allows the client to request STATUS information for
   mailboxes together with other information typically returned by the
   LIST command.

1.1.  Conventions Used in This Document

   In examples, "C:" indicates lines sent by a client that is connected
   to a server.  "S:" indicates lines sent by the server to the client.

   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 [Kwds].

2.  STATUS Return Option to LIST Command

   [RFC3501] explicitly disallows mailbox patterns in the STATUS
   command.  The main reason was to discourage frequent use of the
   STATUS command by clients, as it might be quite expensive for an IMAP
   server to perform.  However, this prohibition had resulted in an
   opposite effect: a new generation of IMAP clients appeared, that
   issues a STATUS command for each mailbox returned by the LIST
   command.  This behavior is suboptimal to say at least.  It wastes
   extra bandwidth and, in the case of a client that doesn't support
   IMAP pipelining, also degrades performance by using too many round
   trips.  This document tries to remedy the situation by specifying a
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