doc: Add RFC documents

1 files changed, 507 insertions, 0 deletions

diff --git a/doc/rfc/rfc3503.txt b/doc/rfc/rfc3503.txt
new file mode 100644
index 0000000..5b82fb0
--- /dev/null
+++ b/doc/rfc/rfc3503.txt
@@ -0,0 +1,507 @@
+
+
+
+
+
+
+Network Working Group                                        A. Melnikov
+Request for Comments: 3503                 ACI Worldwide/MessagingDirect
+Category: Standards Track                                     March 2003
+
+
+          Message Disposition Notification (MDN) profile for
+                Internet Message Access Protocol (IMAP)
+
+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 (2003).  All Rights Reserved.
+
+Abstract
+
+   The Message Disposition Notification (MDN) facility defined in RFC
+   2298 provides a means by which a message can request that message
+   processing by the recipient be acknowledged as well as a format to be
+   used for such acknowledgements.  However, it doesn't describe how
+   multiple Mail User Agents (MUAs) should handle the generation of MDNs
+   in an Internet Message Access Protocol (IMAP4) environment.
+
+   This document describes how to handle MDNs in such an environment and
+   provides guidelines for implementers of IMAP4 that want to add MDN
+   support to their products.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Melnikov                    Standards Track                     [Page 1]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+Table of Contents
+
+   1.  Conventions Used in this Document.............................  2
+   2.  Introduction and Overview.....................................  2
+   3.  Client behavior...............................................  3
+       3.1. Client behavior when receiving a message.................  5
+       3.2. Client behavior when copying a message...................  5
+       3.3. Client behavior when sending a message...................  5
+       3.4. Client behavior when saving a temporary message..........  5
+   4.  Server behavior...............................................  5
+       4.1. Server that supports arbitrary keywords..................  5
+       4.2. Server that supports only $MDNSent keyword...............  5
+       4.3. Interaction with IMAP ACL extension......................  6
+   5.  Examples......................................................  6
+   6.  Security Considerations.......................................  7
+   7.  Formal Syntax.................................................  7
+   8.  Acknowledgments...............................................  7
+   9.  Normative References..........................................  8
+   10. Author's Address..............................................  8
+   11. Full Copyright Statement......................................  9
+
+1.  Conventions Used in this Document
+
+   "C:" and "S:" in examples show lines sent by the client and server
+   respectively.
+
+   The keywords "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in
+   this document when typed in uppercase are to be interpreted as
+   defined in "Key words for use in RFCs to Indicate Requirement Levels"
+   [KEYWORDS].
+
+2.  Introduction and Overview
+
+   This memo defines an additional [IMAP4] mailbox keyword that allows
+   multiple Mail User Agents (MUAs) to know if a requested receipt
+   notification was sent.
+
+   Message Disposition Notification [MDN] does not require any special
+   support of IMAP in the case where a user has access to the mailstore
+   from only one computer and is using a single MUA.  In this case, the
+   MUA behaves as described in [MDN], i.e., the MUA performs automatic
+   processing and generates corresponding MDNs, it performs requested
+   action and, with the user's permission, sends appropriate MDNs.  The
+   MUA will not send MDN twice because the MUA keeps track of sent
+   notifications in a local configuration.  However, that does not work
+   when IMAP is used to access the same mailstore from different
+   locations or is using different MUAs.
+
+
+
+
+Melnikov                    Standards Track                     [Page 2]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+   This document defines a new special purpose mailbox keyword $MDNSent
+   that must be used by MUAs.  It does not define any new command or
+   response for IMAP, but describes a technique that MUAs should use to
+   achieve interoperability.
+
+   When a client opens a mailbox for the first time, it verifies that
+   the server is capable of storing the $MDNSent keyword by examining
+   the PERMANENTFLAGS response code.  In order to support MDN in IMAP, a
+   server MUST support either the $MDNSent keyword, or arbitrary message
+   keywords.
+
+3.  Client behavior
+
+   The use of IMAP requires few additional steps in mail processing on
+   the client side.  The following timeline modifies the timeline found
+   in Section 4 of [MDN].
+
+   -- User composes message.
+
+   -- User tells MUA to send message.
+
+   -- MUA passes message to MSA (original recipient information passed
+      along).  MUA [optionally] saves message to a folder for sent mail
+      with $MDNSent flag set.
+
+   -- MSA sends message to MTA.
+
+   -- Final MTA receives message.
+
+   -- Final MTA delivers message to MUA (possibly generating DSN).
+
+   -- MUA logs into IMAP server, opens mailbox, verifies if mailbox can
+      store $MDNSent keyword by examining PERMANENTFLAGS response.
+
+   -- MUA performs automatic processing and generates corresponding MDNs
+      ("dispatched", "processed", "deleted", "denied" or "failed"
+      disposition type with "automatic-action" and "MDN-sent-
+      automatically" disposition modes) for messages that do not have
+      $MDNSent keyword, or \Draft flag set. (*)
+
+   -- MUA sets the $MDNSent keyword for every message that required an
+      automatic MDN to be sent, whether or not the MDN was sent.
+
+   -- MUA displays a list of messages to user.
+
+   -- User selects a message and requests that some action be performed
+      on it.
+
+
+
+
+Melnikov                    Standards Track                     [Page 3]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+   -- MUA performs requested action and, with user's permission, sends
+      appropriate MDN ("displayed", "dispatched", "processed",
+      "deleted", "denied" or "failed" disposition type with "manual-
+      action" and "MDN-sent-manually" or "MDN-sent-automatically"
+      disposition mode).  If the generated MDN is saved to a mailbox
+      with the APPEND command, the client MUST specify the $MDNSent
+      keyword in the APPEND.
+
+   -- MUA sets the $MDNSent keyword for all messages for which the user
+      confirmed the dispatching of disposition (or was explicitly
+      prohibited to do so).
+
+   -- User possibly performs other actions on message, but no further
+      MDNs are generated.
+
+   (*) Note: MUA MUST NOT use \Recent flag as an indicator that it
+       should send MDN, because according to [IMAP4], "If multiple
+       connections have the same mailbox selected simultaneously, it is
+       undefined which of these connections will see newly-arrived
+       messages with \Recent set and which will see it without \Recent
+       set".  Thus, using \Recent as an indicator will cause
+       unpredictable client behavior with different IMAP4 servers.
+       However, the client MAY use \Seen flag as one of the indicators
+       that MDN must not be sent.  The client MUST NOT use any other
+       standard flags, like \Draft or \Answered, to indicate that MDN
+       was previously sent, because they have different well known
+       meaning.  In any case, in the presence of the $MDNSent keyword,
+       the client MUST ignore all other flags or keywords for the
+       purpose of generating an MDN and MUST NOT send the MDN.
+
+   When the client opens a mailbox for the first time, it must verify
+   that the server supports the $MDNSent keyword, or arbitrary message
+   keywords by examining PERMANENTFLAGS response code.
+
+   The client MUST NOT try to set the $MDNSent keyword if the server is
+   incapable of storing it permanently.
+
+   The client MUST be prepared to receive NO from the server as the
+   result of STORE $MDNSent when the server advertises the support of
+   storing arbitrary keywords, because the server may limit the number
+   of message keywords it can store in a particular mailbox.  A client
+   SHOULD NOT send MDN if it fails to store the $MDNSent keyword.
+
+   Once the $MDNSent keyword is set, it MUST NOT be unset by a client.
+   The client MAY set the $MDNSent keyword when a user denies sending
+   the notification.  This prohibits all other MUAs from sending MDN for
+   this message.
+
+
+
+
+Melnikov                    Standards Track                     [Page 4]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+3.1.  Client behavior when receiving a message
+
+   The client MUST NOT send MDN if a message has the $MDNSent keyword
+   set.  It also MUST NOT send MDN if a message has \Draft flag, because
+   some clients use this flag to mark a message as incomplete.
+
+   See the timeline in section 3 for details on client behavior when
+   receiving a message.
+
+3.2.  Client behavior when copying a message
+
+   The client SHOULD verify that $MDNSent is preserved on a COPY
+   operation.  Furthermore, when a message is copied between servers
+   with the APPEND command, the client MUST set the $MDNSent keyword
+   correctly.
+
+3.3.  Client behavior when sending a message
+
+   When saving a sent message to any folder, the client MUST set the
+   $MDNSent keyword to prevent another client from sending MDN for the
+   message.
+
+3.4.  Client behavior when saving a temporary message
+
+   When saving an unfinished message to any folder client MUST set
+   $MDNSent keyword to prevent another client from sending MDN for the
+   message.
+
+4.  Server behavior
+
+   Server implementors that want to follow this specification must
+   insure that their server complies with either section 4.1 or section
+   4.2.  If the server also supports the IMAP [ACL] extension, it MUST
+   also comply with the section 4.3.
+
+4.1.  Server that supports arbitrary keywords
+
+   No changes are required from the server to make it compatible with
+   the extension described in this document if it supports arbitrary
+   keywords.
+
+4.2.  Server that supports only $MDNSent keyword
+
+   Servers that support only the $MDNSent keyword MUST preserve it on
+   the COPY operation.  It is also expected that a server that supports
+   SEARCH <flag> will also support the SEARCH KEYWORD $MDNSent.
+
+
+
+
+
+Melnikov                    Standards Track                     [Page 5]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+4.3.  Interaction with IMAP ACL extension
+
+   Any server that conforms to either 4.1 or 4.2 and also supports the
+   IMAP [ACL] extension, SHOULD preserve the $MDNSent keyword on COPY
+   even if the client does not have 'w' right.  This will prevent the
+   generation of a duplicated MDN for the same message.  Note that the
+   server MUST still check if the client has rights to perform the COPY
+   operation on a message according to [ACL].
+
+5.  Examples
+
+   1) MUA opens mailbox for the first time.
+
+   a) The server supports storing of arbitrary keywords
+
+   C: a100 select INBOX
+   S: * FLAGS (\Flagged \Draft \Deleted \Seen)
+   S: * OK [PERMANENTFLAGS (\Flagged \Draft \Deleted \Seen \*)]
+   S: * 5 EXISTS
+   S: * 3 RECENT
+   S: * OK [UIDVALIDITY 894294713]
+   S: a100 OK [READ-WRITE] Completed
+
+   b) The server supports storing of the $MDNSent keyword
+
+   C: a100 select INBOX
+   S: * FLAGS (\Flagged \Draft \Deleted \Seen $MDNSent)
+   S: * OK [PERMANENTFLAGS (\Flagged \Draft \Deleted \Seen $MDNSent)]
+   S: * 5 EXISTS
+   S: * 3 RECENT
+   S: * OK [UIDVALIDITY 894294713]
+   S: a100 OK [READ-WRITE] Completed
+
+   2) The MUA successfully sets the $MDNSent keyword
+
+   C: a200 STORE 4 +FLAGS ($MDNSent)
+   S: * 4 FETCH (FLAGS (\Flagged \Seen $MDNSent))
+   S: * FLAGS ($MDNSent \Flagged \Deleted \Draft \Seen)
+   S: * OK [PERMANENTFLAGS ($MDNSent \Flagged \Deleted \Draft \Seen \*)]
+   S: a200 OK STORE completed
+
+   3) The server refuses to store the $MDNSent keyword
+
+   C: a200 STORE 4 +FLAGS ($MDNSent)
+   S: a200 NO STORE failed : no space left to store $MDNSent keyword
+
+
+
+
+
+
+Melnikov                    Standards Track                     [Page 6]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+   4) All clients and servers MUST treat the $MDNSent keyword as case
+   insensitive in all operations, as stated in [IMAP].
+
+   C: a300 FETCH 1:* FLAGS
+   S: * 1 FETCH (FLAGS (\Seen))
+   S: * 2 FETCH (FLAGS (\Answered \Seen $MdnSENt))
+   S: * 3 FETCH (FLAGS ())
+   S: * 4 FETCH (FLAGS (\Flagged \Seen $MdnSENT))
+   S: * 5 FETCH (FLAGS ($MDNSent))
+   S: * 6 FETCH (FLAGS (\Recent))
+   S: a300 OK FETCH completed
+   C: a400 SEARCH KEYWORDS $mdnsent
+   S: * SEARCH 2 4 5
+   S: a400 OK SEARCH completed
+
+6.  Security Considerations
+
+   There are no known security issues with this extension, not found in
+   [MDN] and/or [IMAP4].
+
+   Section 4.3 changes ACL checking requirements on an IMAP server that
+   implements IMAP [ACL] extension.
+
+7.  Formal Syntax
+
+   The following syntax specification uses the augmented Backus-Naur
+   Form (BNF) notation as specified in [RFC-822], as modified by
+   [IMAP4].  Non-terminals referenced, but not defined below, are as
+   defined by [IMAP4].
+
+   Except as noted otherwise, all alphabetic characters are case-
+   insensitive.  The use of upper or lower case characters to define
+   token strings is for editorial clarity only.  Implementations MUST
+   accept these strings in a case-insensitive fashion.
+
+   flag_keyword    ::= "$MDNSent" / other_keywords
+
+   other_keywords  ::= atom
+
+8.  Acknowledgments
+
+   This document is the product of discussions that took place on the
+   IMAP mailing list.  Special gratitude to Cyrus Daboo and Randall
+   Gellens for reviewing the document.
+
+   Thank you to my father who as he has helped to make me what I am.  I
+   miss you terribly.
+
+
+
+
+Melnikov                    Standards Track                     [Page 7]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+9.  Normative References
+
+   [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
+              Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+   [MDN]      Fajman, R., "An Extensible Message Format for Message
+              Disposition Notifications", RFC 2298, March 1998.
+
+   [IMAP4]    Crispin, M., "Internet Message Access Protocol - Version
+              4rev1", RFC 3501, March 2003.
+
+   [ACL]      Myers, J., "IMAP4 ACL extension", RFC 2086, January 1997.
+
+10.  Author's Address
+
+   Alexey Melnikov
+   ACI Worldwide/MessagingDirect
+   59 Clarendon Road
+   Watford, Hertfordshire
+   United Kingdom, WD17 1FQ
+
+   Phone: +44 1923 81 2877
+   EMail: mel@messagingdirect.com
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Melnikov                    Standards Track                     [Page 8]
+
+RFC 3503                  MDN profile for IMAP                March 2003
+
+
+11.  Full Copyright Statement
+
+   Copyright (C) The Internet Society (2003).  All Rights Reserved.
+
+   This document and translations of it may be copied and furnished to
+   others, and derivative works that comment on or otherwise explain it
+   or assist in its implementation may be prepared, copied, published
+   and distributed, in whole or in part, without restriction of any
+   kind, provided that the above copyright notice and this paragraph are
+   included on all such copies and derivative works.  However, this
+   document itself may not be modified in any way, such as by removing
+   the copyright notice or references to the Internet Society or other
+   Internet organizations, except as needed for the purpose of
+   developing Internet standards in which case the procedures for
+   copyrights defined in the Internet Standards process must be
+   followed, or as required to translate it into languages other than
+   English.
+
+   The limited permissions granted above are perpetual and will not be
+   revoked by the Internet Society or its successors or assigns.
+
+   This document and the information contained herein is provided on an
+   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
+   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
+   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
+   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
+   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+
+Acknowledgement
+
+   Funding for the RFC Editor function is currently provided by the
+   Internet Society.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Melnikov                    Standards Track                     [Page 9]
+