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7Network Working Group M. Crispin
8Request for Comments: 2060 University of Washington
9Obsoletes: 1730 December 1996
10Category: Standards Track
11
12
13 INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1
14
15Status of this Memo
16
17 This document specifies an Internet standards track protocol for the
18 Internet community, and requests discussion and suggestions for
19 improvements. Please refer to the current edition of the "Internet
20 Official Protocol Standards" (STD 1) for the standardization state
21 and status of this protocol. Distribution of this memo is unlimited.
22
23Abstract
24
25 The Internet Message Access Protocol, Version 4rev1 (IMAP4rev1)
26 allows a client to access and manipulate electronic mail messages on
27 a server. IMAP4rev1 permits manipulation of remote message folders,
28 called "mailboxes", in a way that is functionally equivalent to local
29 mailboxes. IMAP4rev1 also provides the capability for an offline
30 client to resynchronize with the server (see also [IMAP-DISC]).
31
32 IMAP4rev1 includes operations for creating, deleting, and renaming
33 mailboxes; checking for new messages; permanently removing messages;
34 setting and clearing flags; [RFC-822] and [MIME-IMB] parsing;
35 searching; and selective fetching of message attributes, texts, and
36 portions thereof. Messages in IMAP4rev1 are accessed by the use of
37 numbers. These numbers are either message sequence numbers or unique
38 identifiers.
39
40 IMAP4rev1 supports a single server. A mechanism for accessing
41 configuration information to support multiple IMAP4rev1 servers is
42 discussed in [ACAP].
43
44 IMAP4rev1 does not specify a means of posting mail; this function is
45 handled by a mail transfer protocol such as [SMTP].
46
47 IMAP4rev1 is designed to be upwards compatible from the [IMAP2] and
48 unpublished IMAP2bis protocols. In the course of the evolution of
49 IMAP4rev1, some aspects in the earlier protocol have become obsolete.
50 Obsolete commands, responses, and data formats which an IMAP4rev1
51 implementation may encounter when used with an earlier implementation
52 are described in [IMAP-OBSOLETE].
53
54
55
56
57
58Crispin Standards Track [Page 1]
59
60RFC 2060 IMAP4rev1 December 1996
61
62
63 Other compatibility issues with IMAP2bis, the most common variant of
64 the earlier protocol, are discussed in [IMAP-COMPAT]. A full
65 discussion of compatibility issues with rare (and presumed extinct)
66 variants of [IMAP2] is in [IMAP-HISTORICAL]; this document is
67 primarily of historical interest.
68
69Table of Contents
70
71IMAP4rev1 Protocol Specification .................................. 4
721. How to Read This Document ................................. 4
731.1. Organization of This Document ............................. 4
741.2. Conventions Used in This Document ......................... 4
752. Protocol Overview ......................................... 5
762.1. Link Level ................................................ 5
772.2. Commands and Responses .................................... 6
782.2.1. Client Protocol Sender and Server Protocol Receiver ....... 6
792.2.2. Server Protocol Sender and Client Protocol Receiver ....... 7
802.3. Message Attributes ........................................ 7
812.3.1. Message Numbers ........................................... 7
822.3.1.1. Unique Identifier (UID) Message Attribute ......... 7
832.3.1.2. Message Sequence Number Message Attribute ......... 9
842.3.2. Flags Message Attribute .................................... 9
852.3.3. Internal Date Message Attribute ........................... 10
862.3.4. [RFC-822] Size Message Attribute .......................... 11
872.3.5. Envelope Structure Message Attribute ...................... 11
882.3.6. Body Structure Message Attribute .......................... 11
892.4. Message Texts ............................................. 11
903. State and Flow Diagram .................................... 11
913.1. Non-Authenticated State ................................... 11
923.2. Authenticated State ....................................... 11
933.3. Selected State ............................................ 12
943.4. Logout State .............................................. 12
954. Data Formats .............................................. 12
964.1. Atom ...................................................... 13
974.2. Number .................................................... 13
984.3. String ..................................................... 13
994.3.1. 8-bit and Binary Strings .................................. 13
1004.4. Parenthesized List ........................................ 14
1014.5. NIL ....................................................... 14
1025. Operational Considerations ................................ 14
1035.1. Mailbox Naming ............................................ 14
1045.1.1. Mailbox Hierarchy Naming .................................. 14
1055.1.2. Mailbox Namespace Naming Convention ....................... 14
1065.1.3. Mailbox International Naming Convention ................... 15
1075.2. Mailbox Size and Message Status Updates ................... 16
1085.3. Response when no Command in Progress ...................... 16
1095.4. Autologout Timer .......................................... 16
1105.5. Multiple Commands in Progress ............................. 17
111
112
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114Crispin Standards Track [Page 2]
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116RFC 2060 IMAP4rev1 December 1996
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118
1196. Client Commands ........................................... 17
1206.1. Client Commands - Any State ............................... 18
1216.1.1. CAPABILITY Command ........................................ 18
1226.1.2. NOOP Command .............................................. 19
1236.1.3. LOGOUT Command ............................................ 20
1246.2. Client Commands - Non-Authenticated State ................. 20
1256.2.1. AUTHENTICATE Command ...................................... 21
1266.2.2. LOGIN Command ............................................. 22
1276.3. Client Commands - Authenticated State ..................... 22
1286.3.1. SELECT Command ............................................ 23
1296.3.2. EXAMINE Command ........................................... 24
1306.3.3. CREATE Command ............................................ 25
1316.3.4. DELETE Command ............................................ 26
1326.3.5. RENAME Command ............................................ 27
1336.3.6. SUBSCRIBE Command ......................................... 29
1346.3.7. UNSUBSCRIBE Command ....................................... 30
1356.3.8. LIST Command .............................................. 30
1366.3.9. LSUB Command .............................................. 32
1376.3.10. STATUS Command ............................................ 33
1386.3.11. APPEND Command ............................................ 34
1396.4. Client Commands - Selected State .......................... 35
1406.4.1. CHECK Command ............................................. 36
1416.4.2. CLOSE Command ............................................. 36
1426.4.3. EXPUNGE Command ........................................... 37
1436.4.4. SEARCH Command ............................................ 37
1446.4.5. FETCH Command ............................................. 41
1456.4.6. STORE Command ............................................. 45
1466.4.7. COPY Command .............................................. 46
1476.4.8. UID Command ............................................... 47
1486.5. Client Commands - Experimental/Expansion .................. 48
1496.5.1. X<atom> Command ........................................... 48
1507. Server Responses .......................................... 48
1517.1. Server Responses - Status Responses ....................... 49
1527.1.1. OK Response ............................................... 51
1537.1.2. NO Response ............................................... 51
1547.1.3. BAD Response .............................................. 52
1557.1.4. PREAUTH Response .......................................... 52
1567.1.5. BYE Response .............................................. 52
1577.2. Server Responses - Server and Mailbox Status .............. 53
1587.2.1. CAPABILITY Response ....................................... 53
1597.2.2. LIST Response .............................................. 54
1607.2.3. LSUB Response ............................................. 55
1617.2.4 STATUS Response ........................................... 55
1627.2.5. SEARCH Response ........................................... 55
1637.2.6. FLAGS Response ............................................ 56
1647.3. Server Responses - Mailbox Size ........................... 56
1657.3.1. EXISTS Response ........................................... 56
1667.3.2. RECENT Response ........................................... 57
167
168
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170Crispin Standards Track [Page 3]
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172RFC 2060 IMAP4rev1 December 1996
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174
1757.4. Server Responses - Message Status ......................... 57
1767.4.1. EXPUNGE Response .......................................... 57
1777.4.2. FETCH Response ............................................ 58
1787.5. Server Responses - Command Continuation Request ........... 63
1798. Sample IMAP4rev1 connection ............................... 63
1809. Formal Syntax ............................................. 64
18110. Author's Note ............................................. 74
18211. Security Considerations ................................... 74
18312. Author's Address .......................................... 75
184Appendices ........................................................ 76
185A. References ................................................ 76
186B. Changes from RFC 1730 ..................................... 77
187C. Key Word Index ............................................ 79
188
189
190IMAP4rev1 Protocol Specification
191
1921. How to Read This Document
193
1941.1. Organization of This Document
195
196 This document is written from the point of view of the implementor of
197 an IMAP4rev1 client or server. Beyond the protocol overview in
198 section 2, it is not optimized for someone trying to understand the
199 operation of the protocol. The material in sections 3 through 5
200 provides the general context and definitions with which IMAP4rev1
201 operates.
202
203 Sections 6, 7, and 9 describe the IMAP commands, responses, and
204 syntax, respectively. The relationships among these are such that it
205 is almost impossible to understand any of them separately. In
206 particular, do not attempt to deduce command syntax from the command
207 section alone; instead refer to the Formal Syntax section.
208
2091.2. Conventions Used in This Document
210
211 In examples, "C:" and "S:" indicate lines sent by the client and
212 server respectively.
213
214 The following terms are used in this document to signify the
215 requirements of this specification.
216
217 1) MUST, or the adjective REQUIRED, means that the definition is
218 an absolute requirement of the specification.
219
220 2) MUST NOT that the definition is an absolute prohibition of the
221 specification.
222
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226Crispin Standards Track [Page 4]
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228RFC 2060 IMAP4rev1 December 1996
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230
231 3) SHOULD means that there may exist valid reasons in particular
232 circumstances to ignore a particular item, but the full
233 implications MUST be understood and carefully weighed before
234 choosing a different course.
235
236 4) SHOULD NOT means that there may exist valid reasons in
237 particular circumstances when the particular behavior is
238 acceptable or even useful, but the full implications SHOULD be
239 understood and the case carefully weighed before implementing
240 any behavior described with this label.
241
242 5) MAY, or the adjective OPTIONAL, means that an item is truly
243 optional. One vendor may choose to include the item because a
244 particular marketplace requires it or because the vendor feels
245 that it enhances the product while another vendor may omit the
246 same item. An implementation which does not include a
247 particular option MUST be prepared to interoperate with another
248 implementation which does include the option.
249
250 "Can" is used instead of "may" when referring to a possible
251 circumstance or situation, as opposed to an optional facility of
252 the protocol.
253
254 "User" is used to refer to a human user, whereas "client" refers
255 to the software being run by the user.
256
257 "Connection" refers to the entire sequence of client/server
258 interaction from the initial establishment of the network
259 connection until its termination. "Session" refers to the
260 sequence of client/server interaction from the time that a mailbox
261 is selected (SELECT or EXAMINE command) until the time that
262 selection ends (SELECT or EXAMINE of another mailbox, CLOSE
263 command, or connection termination).
264
265 Characters are 7-bit US-ASCII unless otherwise specified. Other
266 character sets are indicated using a "CHARSET", as described in
267 [MIME-IMT] and defined in [CHARSET]. CHARSETs have important
268 additional semantics in addition to defining character set; refer
269 to these documents for more detail.
270
2712. Protocol Overview
272
2732.1. Link Level
274
275 The IMAP4rev1 protocol assumes a reliable data stream such as
276 provided by TCP. When TCP is used, an IMAP4rev1 server listens on
277 port 143.
278
279
280
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282Crispin Standards Track [Page 5]
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284RFC 2060 IMAP4rev1 December 1996
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286
2872.2. Commands and Responses
288
289 An IMAP4rev1 connection consists of the establishment of a
290 client/server network connection, an initial greeting from the
291 server, and client/server interactions. These client/server
292 interactions consist of a client command, server data, and a server
293 completion result response.
294
295 All interactions transmitted by client and server are in the form of
296 lines; that is, strings that end with a CRLF. The protocol receiver
297 of an IMAP4rev1 client or server is either reading a line, or is
298 reading a sequence of octets with a known count followed by a line.
299
3002.2.1. Client Protocol Sender and Server Protocol Receiver
301
302 The client command begins an operation. Each client command is
303 prefixed with an identifier (typically a short alphanumeric string,
304 e.g. A0001, A0002, etc.) called a "tag". A different tag is
305 generated by the client for each command.
306
307 There are two cases in which a line from the client does not
308 represent a complete command. In one case, a command argument is
309 quoted with an octet count (see the description of literal in String
310 under Data Formats); in the other case, the command arguments require
311 server feedback (see the AUTHENTICATE command). In either case, the
312 server sends a command continuation request response if it is ready
313 for the octets (if appropriate) and the remainder of the command.
314 This response is prefixed with the token "+".
315
316 Note: If, instead, the server detected an error in the command, it
317 sends a BAD completion response with tag matching the command (as
318 described below) to reject the command and prevent the client from
319 sending any more of the command.
320
321 It is also possible for the server to send a completion response
322 for some other command (if multiple commands are in progress), or
323 untagged data. In either case, the command continuation request
324 is still pending; the client takes the appropriate action for the
325 response, and reads another response from the server. In all
326 cases, the client MUST send a complete command (including
327 receiving all command continuation request responses and command
328 continuations for the command) before initiating a new command.
329
330 The protocol receiver of an IMAP4rev1 server reads a command line
331 from the client, parses the command and its arguments, and transmits
332 server data and a server command completion result response.
333
334
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336
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338Crispin Standards Track [Page 6]
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340RFC 2060 IMAP4rev1 December 1996
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342
3432.2.2. Server Protocol Sender and Client Protocol Receiver
344
345 Data transmitted by the server to the client and status responses
346 that do not indicate command completion are prefixed with the token
347 "*", and are called untagged responses.
348
349 Server data MAY be sent as a result of a client command, or MAY be
350 sent unilaterally by the server. There is no syntactic difference
351 between server data that resulted from a specific command and server
352 data that were sent unilaterally.
353
354 The server completion result response indicates the success or
355 failure of the operation. It is tagged with the same tag as the
356 client command which began the operation. Thus, if more than one
357 command is in progress, the tag in a server completion response
358 identifies the command to which the response applies. There are
359 three possible server completion responses: OK (indicating success),
360 NO (indicating failure), or BAD (indicating protocol error such as
361 unrecognized command or command syntax error).
362
363 The protocol receiver of an IMAP4rev1 client reads a response line
364 from the server. It then takes action on the response based upon the
365 first token of the response, which can be a tag, a "*", or a "+".
366
367 A client MUST be prepared to accept any server response at all times.
368 This includes server data that was not requested. Server data SHOULD
369 be recorded, so that the client can reference its recorded copy
370 rather than sending a command to the server to request the data. In
371 the case of certain server data, the data MUST be recorded.
372
373 This topic is discussed in greater detail in the Server Responses
374 section.
375
3762.3. Message Attributes
377
378 In addition to message text, each message has several attributes
379 associated with it. These attributes may be retrieved individually
380 or in conjunction with other attributes or message texts.
381
3822.3.1. Message Numbers
383
384 Messages in IMAP4rev1 are accessed by one of two numbers; the unique
385 identifier and the message sequence number.
386
3872.3.1.1. Unique Identifier (UID) Message Attribute
388
389 A 32-bit value assigned to each message, which when used with the
390 unique identifier validity value (see below) forms a 64-bit value
391
392
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394Crispin Standards Track [Page 7]
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396RFC 2060 IMAP4rev1 December 1996
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398
399 that is permanently guaranteed not to refer to any other message in
400 the mailbox. Unique identifiers are assigned in a strictly ascending
401 fashion in the mailbox; as each message is added to the mailbox it is
402 assigned a higher UID than the message(s) which were added
403 previously.
404
405 Unlike message sequence numbers, unique identifiers are not
406 necessarily contiguous. Unique identifiers also persist across
407 sessions. This permits a client to resynchronize its state from a
408 previous session with the server (e.g. disconnected or offline access
409 clients); this is discussed further in [IMAP-DISC].
410
411 Associated with every mailbox is a unique identifier validity value,
412 which is sent in an UIDVALIDITY response code in an OK untagged
413 response at mailbox selection time. If unique identifiers from an
414 earlier session fail to persist to this session, the unique
415 identifier validity value MUST be greater than the one used in the
416 earlier session.
417
418 Note: Unique identifiers MUST be strictly ascending in the mailbox
419 at all times. If the physical message store is re-ordered by a
420 non-IMAP agent, this requires that the unique identifiers in the
421 mailbox be regenerated, since the former unique identifers are no
422 longer strictly ascending as a result of the re-ordering. Another
423 instance in which unique identifiers are regenerated is if the
424 message store has no mechanism to store unique identifiers.
425 Although this specification recognizes that this may be
426 unavoidable in certain server environments, it STRONGLY ENCOURAGES
427 message store implementation techniques that avoid this problem.
428
429 Another cause of non-persistance is if the mailbox is deleted and
430 a new mailbox with the same name is created at a later date, Since
431 the name is the same, a client may not know that this is a new
432 mailbox unless the unique identifier validity is different. A
433 good value to use for the unique identifier validity value is a
434 32-bit representation of the creation date/time of the mailbox.
435 It is alright to use a constant such as 1, but only if it
436 guaranteed that unique identifiers will never be reused, even in
437 the case of a mailbox being deleted (or renamed) and a new mailbox
438 by the same name created at some future time.
439
440 The unique identifier of a message MUST NOT change during the
441 session, and SHOULD NOT change between sessions. However, if it is
442 not possible to preserve the unique identifier of a message in a
443 subsequent session, each subsequent session MUST have a new unique
444 identifier validity value that is larger than any that was used
445 previously.
446
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450Crispin Standards Track [Page 8]
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452RFC 2060 IMAP4rev1 December 1996
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454
4552.3.1.2. Message Sequence Number Message Attribute
456
457 A relative position from 1 to the number of messages in the mailbox.
458 This position MUST be ordered by ascending unique identifier. As
459 each new message is added, it is assigned a message sequence number
460 that is 1 higher than the number of messages in the mailbox before
461 that new message was added.
462
463 Message sequence numbers can be reassigned during the session. For
464 example, when a message is permanently removed (expunged) from the
465 mailbox, the message sequence number for all subsequent messages is
466 decremented. Similarly, a new message can be assigned a message
467 sequence number that was once held by some other message prior to an
468 expunge.
469
470 In addition to accessing messages by relative position in the
471 mailbox, message sequence numbers can be used in mathematical
472 calculations. For example, if an untagged "EXISTS 11" is received,
473 and previously an untagged "8 EXISTS" was received, three new
474 messages have arrived with message sequence numbers of 9, 10, and 11.
475 Another example; if message 287 in a 523 message mailbox has UID
476 12345, there are exactly 286 messages which have lesser UIDs and 236
477 messages which have greater UIDs.
478
4792.3.2. Flags Message Attribute
480
481 A list of zero or more named tokens associated with the message. A
482 flag is set by its addition to this list, and is cleared by its
483 removal. There are two types of flags in IMAP4rev1. A flag of
484 either type may be permanent or session-only.
485
486 A system flag is a flag name that is pre-defined in this
487 specification. All system flags begin with "\". Certain system
488 flags (\Deleted and \Seen) have special semantics described
489 elsewhere. The currently-defined system flags are:
490
491 \Seen Message has been read
492
493 \Answered Message has been answered
494
495 \Flagged Message is "flagged" for urgent/special attention
496
497 \Deleted Message is "deleted" for removal by later EXPUNGE
498
499 \Draft Message has not completed composition (marked as a
500 draft).
501
502
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506Crispin Standards Track [Page 9]
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508RFC 2060 IMAP4rev1 December 1996
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510
511 \Recent Message is "recently" arrived in this mailbox. This
512 session is the first session to have been notified
513 about this message; subsequent sessions will not see
514 \Recent set for this message. This flag can not be
515 altered by the client.
516
517 If it is not possible to determine whether or not
518 this session is the first session to be notified
519 about a message, then that message SHOULD be
520 considered recent.
521
522 If multiple connections have the same mailbox
523 selected simultaneously, it is undefined which of
524 these connections will see newly-arrives messages
525 with \Recent set and which will see it without
526 \Recent set.
527
528 A keyword is defined by the server implementation. Keywords do
529 not begin with "\". Servers MAY permit the client to define new
530 keywords in the mailbox (see the description of the
531 PERMANENTFLAGS response code for more information).
532
533 A flag may be permanent or session-only on a per-flag basis.
534 Permanent flags are those which the client can add or remove
535 from the message flags permanently; that is, subsequent sessions
536 will see any change in permanent flags. Changes to session
537 flags are valid only in that session.
538
539 Note: The \Recent system flag is a special case of a
540 session flag. \Recent can not be used as an argument in a
541 STORE command, and thus can not be changed at all.
542
5432.3.3. Internal Date Message Attribute
544
545 The internal date and time of the message on the server. This is not
546 the date and time in the [RFC-822] header, but rather a date and time
547 which reflects when the message was received. In the case of
548 messages delivered via [SMTP], this SHOULD be the date and time of
549 final delivery of the message as defined by [SMTP]. In the case of
550 messages delivered by the IMAP4rev1 COPY command, this SHOULD be the
551 internal date and time of the source message. In the case of
552 messages delivered by the IMAP4rev1 APPEND command, this SHOULD be
553 the date and time as specified in the APPEND command description.
554 All other cases are implementation defined.
555
556
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562Crispin Standards Track [Page 10]
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564RFC 2060 IMAP4rev1 December 1996
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566
5672.3.4. [RFC-822] Size Message Attribute
568
569 The number of octets in the message, as expressed in [RFC-822]
570 format.
571
5722.3.5. Envelope Structure Message Attribute
573
574 A parsed representation of the [RFC-822] envelope information (not to
575 be confused with an [SMTP] envelope) of the message.
576
5772.3.6. Body Structure Message Attribute
578
579 A parsed representation of the [MIME-IMB] body structure information
580 of the message.
581
5822.4. Message Texts
583
584 In addition to being able to fetch the full [RFC-822] text of a
585 message, IMAP4rev1 permits the fetching of portions of the full
586 message text. Specifically, it is possible to fetch the [RFC-822]
587 message header, [RFC-822] message body, a [MIME-IMB] body part, or a
588 [MIME-IMB] header.
589
5903. State and Flow Diagram
591
592 An IMAP4rev1 server is in one of four states. Most commands are
593 valid in only certain states. It is a protocol error for the client
594 to attempt a command while the command is in an inappropriate state.
595 In this case, a server will respond with a BAD or NO (depending upon
596 server implementation) command completion result.
597
5983.1. Non-Authenticated State
599
600 In non-authenticated state, the client MUST supply authentication
601 credentials before most commands will be permitted. This state is
602 entered when a connection starts unless the connection has been pre-
603 authenticated.
604
6053.2. Authenticated State
606
607 In authenticated state, the client is authenticated and MUST select a
608 mailbox to access before commands that affect messages will be
609 permitted. This state is entered when a pre-authenticated connection
610 starts, when acceptable authentication credentials have been
611 provided, or after an error in selecting a mailbox.
612
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620RFC 2060 IMAP4rev1 December 1996
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622
6233.3. Selected State
624
625 In selected state, a mailbox has been selected to access. This state
626 is entered when a mailbox has been successfully selected.
627
6283.4. Logout State
629
630 In logout state, the connection is being terminated, and the server
631 will close the connection. This state can be entered as a result of
632 a client request or by unilateral server decision.
633
634 +--------------------------------------+
635 |initial connection and server greeting|
636 +--------------------------------------+
637 || (1) || (2) || (3)
638 VV || ||
639 +-----------------+ || ||
640 |non-authenticated| || ||
641 +-----------------+ || ||
642 || (7) || (4) || ||
643 || VV VV ||
644 || +----------------+ ||
645 || | authenticated |<=++ ||
646 || +----------------+ || ||
647 || || (7) || (5) || (6) ||
648 || || VV || ||
649 || || +--------+ || ||
650 || || |selected|==++ ||
651 || || +--------+ ||
652 || || || (7) ||
653 VV VV VV VV
654 +--------------------------------------+
655 | logout and close connection |
656 +--------------------------------------+
657
658 (1) connection without pre-authentication (OK greeting)
659 (2) pre-authenticated connection (PREAUTH greeting)
660 (3) rejected connection (BYE greeting)
661 (4) successful LOGIN or AUTHENTICATE command
662 (5) successful SELECT or EXAMINE command
663 (6) CLOSE command, or failed SELECT or EXAMINE command
664 (7) LOGOUT command, server shutdown, or connection closed
665
6664. Data Formats
667
668 IMAP4rev1 uses textual commands and responses. Data in IMAP4rev1 can
669 be in one of several forms: atom, number, string, parenthesized list,
670 or NIL.
671
672
673
674Crispin Standards Track [Page 12]
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676RFC 2060 IMAP4rev1 December 1996
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678
6794.1. Atom
680
681 An atom consists of one or more non-special characters.
682
6834.2. Number
684
685 A number consists of one or more digit characters, and represents a
686 numeric value.
687
6884.3. String
689
690 A string is in one of two forms: literal and quoted string. The
691 literal form is the general form of string. The quoted string form
692 is an alternative that avoids the overhead of processing a literal at
693 the cost of limitations of characters that can be used in a quoted
694 string.
695
696 A literal is a sequence of zero or more octets (including CR and LF),
697 prefix-quoted with an octet count in the form of an open brace ("{"),
698 the number of octets, close brace ("}"), and CRLF. In the case of
699 literals transmitted from server to client, the CRLF is immediately
700 followed by the octet data. In the case of literals transmitted from
701 client to server, the client MUST wait to receive a command
702 continuation request (described later in this document) before
703 sending the octet data (and the remainder of the command).
704
705 A quoted string is a sequence of zero or more 7-bit characters,
706 excluding CR and LF, with double quote (<">) characters at each end.
707
708 The empty string is represented as either "" (a quoted string with
709 zero characters between double quotes) or as {0} followed by CRLF (a
710 literal with an octet count of 0).
711
712 Note: Even if the octet count is 0, a client transmitting a
713 literal MUST wait to receive a command continuation request.
714
7154.3.1. 8-bit and Binary Strings
716
717 8-bit textual and binary mail is supported through the use of a
718 [MIME-IMB] content transfer encoding. IMAP4rev1 implementations MAY
719 transmit 8-bit or multi-octet characters in literals, but SHOULD do
720 so only when the [CHARSET] is identified.
721
722
723
724
725
726
727
728
729
730Crispin Standards Track [Page 13]
731
732RFC 2060 IMAP4rev1 December 1996
733
734
735 Although a BINARY body encoding is defined, unencoded binary strings
736 are not permitted. A "binary string" is any string with NUL
737 characters. Implementations MUST encode binary data into a textual
738 form such as BASE64 before transmitting the data. A string with an
739 excessive amount of CTL characters MAY also be considered to be
740 binary.
741
7424.4. Parenthesized List
743
744 Data structures are represented as a "parenthesized list"; a sequence
745 of data items, delimited by space, and bounded at each end by
746 parentheses. A parenthesized list can contain other parenthesized
747 lists, using multiple levels of parentheses to indicate nesting.
748
749 The empty list is represented as () -- a parenthesized list with no
750 members.
751
7524.5. NIL
753
754 The special atom "NIL" represents the non-existence of a particular
755 data item that is represented as a string or parenthesized list, as
756 distinct from the empty string "" or the empty parenthesized list ().
757
7585. Operational Considerations
759
7605.1. Mailbox Naming
761
762 The interpretation of mailbox names is implementation-dependent.
763 However, the case-insensitive mailbox name INBOX is a special name
764 reserved to mean "the primary mailbox for this user on this server".
765
7665.1.1. Mailbox Hierarchy Naming
767
768 If it is desired to export hierarchical mailbox names, mailbox names
769 MUST be left-to-right hierarchical using a single character to
770 separate levels of hierarchy. The same hierarchy separator character
771 is used for all levels of hierarchy within a single name.
772
7735.1.2. Mailbox Namespace Naming Convention
774
775 By convention, the first hierarchical element of any mailbox name
776 which begins with "#" identifies the "namespace" of the remainder of
777 the name. This makes it possible to disambiguate between different
778 types of mailbox stores, each of which have their own namespaces.
779
780
781
782
783
784
785
786Crispin Standards Track [Page 14]
787
788RFC 2060 IMAP4rev1 December 1996
789
790
791 For example, implementations which offer access to USENET
792 newsgroups MAY use the "#news" namespace to partition the USENET
793 newsgroup namespace from that of other mailboxes. Thus, the
794 comp.mail.misc newsgroup would have an mailbox name of
795 "#news.comp.mail.misc", and the name "comp.mail.misc" could refer
796 to a different object (e.g. a user's private mailbox).
797
7985.1.3. Mailbox International Naming Convention
799
800 By convention, international mailbox names are specified using a
801 modified version of the UTF-7 encoding described in [UTF-7]. The
802 purpose of these modifications is to correct the following problems
803 with UTF-7:
804
805 1) UTF-7 uses the "+" character for shifting; this conflicts with
806 the common use of "+" in mailbox names, in particular USENET
807 newsgroup names.
808
809 2) UTF-7's encoding is BASE64 which uses the "/" character; this
810 conflicts with the use of "/" as a popular hierarchy delimiter.
811
812 3) UTF-7 prohibits the unencoded usage of "\"; this conflicts with
813 the use of "\" as a popular hierarchy delimiter.
814
815 4) UTF-7 prohibits the unencoded usage of "~"; this conflicts with
816 the use of "~" in some servers as a home directory indicator.
817
818 5) UTF-7 permits multiple alternate forms to represent the same
819 string; in particular, printable US-ASCII chararacters can be
820 represented in encoded form.
821
822 In modified UTF-7, printable US-ASCII characters except for "&"
823 represent themselves; that is, characters with octet values 0x20-0x25
824 and 0x27-0x7e. The character "&" (0x26) is represented by the two-
825 octet sequence "&-".
826
827 All other characters (octet values 0x00-0x1f, 0x7f-0xff, and all
828 Unicode 16-bit octets) are represented in modified BASE64, with a
829 further modification from [UTF-7] that "," is used instead of "/".
830 Modified BASE64 MUST NOT be used to represent any printing US-ASCII
831 character which can represent itself.
832
833 "&" is used to shift to modified BASE64 and "-" to shift back to US-
834 ASCII. All names start in US-ASCII, and MUST end in US-ASCII (that
835 is, a name that ends with a Unicode 16-bit octet MUST end with a "-
836 ").
837
838
839
840
841
842Crispin Standards Track [Page 15]
843
844RFC 2060 IMAP4rev1 December 1996
845
846
847 For example, here is a mailbox name which mixes English, Japanese,
848 and Chinese text: ~peter/mail/&ZeVnLIqe-/&U,BTFw-
849
8505.2. Mailbox Size and Message Status Updates
851
852 At any time, a server can send data that the client did not request.
853 Sometimes, such behavior is REQUIRED. For example, agents other than
854 the server MAY add messages to the mailbox (e.g. new mail delivery),
855 change the flags of message in the mailbox (e.g. simultaneous access
856 to the same mailbox by multiple agents), or even remove messages from
857 the mailbox. A server MUST send mailbox size updates automatically
858 if a mailbox size change is observed during the processing of a
859 command. A server SHOULD send message flag updates automatically,
860 without requiring the client to request such updates explicitly.
861 Special rules exist for server notification of a client about the
862 removal of messages to prevent synchronization errors; see the
863 description of the EXPUNGE response for more detail.
864
865 Regardless of what implementation decisions a client makes on
866 remembering data from the server, a client implementation MUST record
867 mailbox size updates. It MUST NOT assume that any command after
868 initial mailbox selection will return the size of the mailbox.
869
8705.3. Response when no Command in Progress
871
872 Server implementations are permitted to send an untagged response
873 (except for EXPUNGE) while there is no command in progress. Server
874 implementations that send such responses MUST deal with flow control
875 considerations. Specifically, they MUST either (1) verify that the
876 size of the data does not exceed the underlying transport's available
877 window size, or (2) use non-blocking writes.
878
8795.4. Autologout Timer
880
881 If a server has an inactivity autologout timer, that timer MUST be of
882 at least 30 minutes' duration. The receipt of ANY command from the
883 client during that interval SHOULD suffice to reset the autologout
884 timer.
885
886
887
888
889
890
891
892
893
894
895
896
897
898Crispin Standards Track [Page 16]
899
900RFC 2060 IMAP4rev1 December 1996
901
902
9035.5. Multiple Commands in Progress
904
905 The client MAY send another command without waiting for the
906 completion result response of a command, subject to ambiguity rules
907 (see below) and flow control constraints on the underlying data
908 stream. Similarly, a server MAY begin processing another command
909 before processing the current command to completion, subject to
910 ambiguity rules. However, any command continuation request responses
911 and command continuations MUST be negotiated before any subsequent
912 command is initiated.
913
914 The exception is if an ambiguity would result because of a command
915 that would affect the results of other commands. Clients MUST NOT
916 send multiple commands without waiting if an ambiguity would result.
917 If the server detects a possible ambiguity, it MUST execute commands
918 to completion in the order given by the client.
919
920 The most obvious example of ambiguity is when a command would affect
921 the results of another command; for example, a FETCH of a message's
922 flags and a STORE of that same message's flags.
923
924 A non-obvious ambiguity occurs with commands that permit an untagged
925 EXPUNGE response (commands other than FETCH, STORE, and SEARCH),
926 since an untagged EXPUNGE response can invalidate sequence numbers in
927 a subsequent command. This is not a problem for FETCH, STORE, or
928 SEARCH commands because servers are prohibited from sending EXPUNGE
929 responses while any of those commands are in progress. Therefore, if
930 the client sends any command other than FETCH, STORE, or SEARCH, it
931 MUST wait for a response before sending a command with message
932 sequence numbers.
933
934 For example, the following non-waiting command sequences are invalid:
935
936 FETCH + NOOP + STORE
937 STORE + COPY + FETCH
938 COPY + COPY
939 CHECK + FETCH
940
941 The following are examples of valid non-waiting command sequences:
942
943 FETCH + STORE + SEARCH + CHECK
944 STORE + COPY + EXPUNGE
945
9466. Client Commands
947
948 IMAP4rev1 commands are described in this section. Commands are
949 organized by the state in which the command is permitted. Commands
950 which are permitted in multiple states are listed in the minimum
951
952
953
954Crispin Standards Track [Page 17]
955
956RFC 2060 IMAP4rev1 December 1996
957
958
959 permitted state (for example, commands valid in authenticated and
960 selected state are listed in the authenticated state commands).
961
962 Command arguments, identified by "Arguments:" in the command
963 descriptions below, are described by function, not by syntax. The
964 precise syntax of command arguments is described in the Formal Syntax
965 section.
966
967 Some commands cause specific server responses to be returned; these
968 are identified by "Responses:" in the command descriptions below.
969 See the response descriptions in the Responses section for
970 information on these responses, and the Formal Syntax section for the
971 precise syntax of these responses. It is possible for server data to
972 be transmitted as a result of any command; thus, commands that do not
973 specifically require server data specify "no specific responses for
974 this command" instead of "none".
975
976 The "Result:" in the command description refers to the possible
977 tagged status responses to a command, and any special interpretation
978 of these status responses.
979
9806.1. Client Commands - Any State
981
982 The following commands are valid in any state: CAPABILITY, NOOP, and
983 LOGOUT.
984
9856.1.1. CAPABILITY Command
986
987 Arguments: none
988
989 Responses: REQUIRED untagged response: CAPABILITY
990
991 Result: OK - capability completed
992 BAD - command unknown or arguments invalid
993
994 The CAPABILITY command requests a listing of capabilities that the
995 server supports. The server MUST send a single untagged
996 CAPABILITY response with "IMAP4rev1" as one of the listed
997 capabilities before the (tagged) OK response. This listing of
998 capabilities is not dependent upon connection state or user. It
999 is therefore not necessary to issue a CAPABILITY command more than
1000 once in a connection.
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010Crispin Standards Track [Page 18]
1011
1012RFC 2060 IMAP4rev1 December 1996
1013
1014
1015 A capability name which begins with "AUTH=" indicates that the
1016 server supports that particular authentication mechanism. All
1017 such names are, by definition, part of this specification. For
1018 example, the authorization capability for an experimental
1019 "blurdybloop" authenticator would be "AUTH=XBLURDYBLOOP" and not
1020 "XAUTH=BLURDYBLOOP" or "XAUTH=XBLURDYBLOOP".
1021
1022 Other capability names refer to extensions, revisions, or
1023 amendments to this specification. See the documentation of the
1024 CAPABILITY response for additional information. No capabilities,
1025 beyond the base IMAP4rev1 set defined in this specification, are
1026 enabled without explicit client action to invoke the capability.
1027
1028 See the section entitled "Client Commands -
1029 Experimental/Expansion" for information about the form of site or
1030 implementation-specific capabilities.
1031
1032 Example: C: abcd CAPABILITY
1033 S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4
1034 S: abcd OK CAPABILITY completed
1035
10366.1.2. NOOP Command
1037
1038 Arguments: none
1039
1040 Responses: no specific responses for this command (but see below)
1041
1042 Result: OK - noop completed
1043 BAD - command unknown or arguments invalid
1044
1045 The NOOP command always succeeds. It does nothing.
1046
1047 Since any command can return a status update as untagged data, the
1048 NOOP command can be used as a periodic poll for new messages or
1049 message status updates during a period of inactivity. The NOOP
1050 command can also be used to reset any inactivity autologout timer
1051 on the server.
1052
1053 Example: C: a002 NOOP
1054 S: a002 OK NOOP completed
1055 . . .
1056 C: a047 NOOP
1057 S: * 22 EXPUNGE
1058 S: * 23 EXISTS
1059 S: * 3 RECENT
1060 S: * 14 FETCH (FLAGS (\Seen \Deleted))
1061 S: a047 OK NOOP completed
1062
1063
1064
1065
1066Crispin Standards Track [Page 19]
1067
1068RFC 2060 IMAP4rev1 December 1996
1069
1070
10716.1.3. LOGOUT Command
1072
1073 Arguments: none
1074
1075 Responses: REQUIRED untagged response: BYE
1076
1077 Result: OK - logout completed
1078 BAD - command unknown or arguments invalid
1079
1080 The LOGOUT command informs the server that the client is done with
1081 the connection. The server MUST send a BYE untagged response
1082 before the (tagged) OK response, and then close the network
1083 connection.
1084
1085 Example: C: A023 LOGOUT
1086 S: * BYE IMAP4rev1 Server logging out
1087 S: A023 OK LOGOUT completed
1088 (Server and client then close the connection)
1089
10906.2. Client Commands - Non-Authenticated State
1091
1092 In non-authenticated state, the AUTHENTICATE or LOGIN command
1093 establishes authentication and enter authenticated state. The
1094 AUTHENTICATE command provides a general mechanism for a variety of
1095 authentication techniques, whereas the LOGIN command uses the
1096 traditional user name and plaintext password pair.
1097
1098 Server implementations MAY allow non-authenticated access to certain
1099 mailboxes. The convention is to use a LOGIN command with the userid
1100 "anonymous". A password is REQUIRED. It is implementation-dependent
1101 what requirements, if any, are placed on the password and what access
1102 restrictions are placed on anonymous users.
1103
1104 Once authenticated (including as anonymous), it is not possible to
1105 re-enter non-authenticated state.
1106
1107 In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
1108 the following commands are valid in non-authenticated state:
1109 AUTHENTICATE and LOGIN.
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122Crispin Standards Track [Page 20]
1123
1124RFC 2060 IMAP4rev1 December 1996
1125
1126
11276.2.1. AUTHENTICATE Command
1128
1129 Arguments: authentication mechanism name
1130
1131 Responses: continuation data can be requested
1132
1133 Result: OK - authenticate completed, now in authenticated state
1134 NO - authenticate failure: unsupported authentication
1135 mechanism, credentials rejected
1136 BAD - command unknown or arguments invalid,
1137 authentication exchange cancelled
1138
1139 The AUTHENTICATE command indicates an authentication mechanism,
1140 such as described in [IMAP-AUTH], to the server. If the server
1141 supports the requested authentication mechanism, it performs an
1142 authentication protocol exchange to authenticate and identify the
1143 client. It MAY also negotiate an OPTIONAL protection mechanism
1144 for subsequent protocol interactions. If the requested
1145 authentication mechanism is not supported, the server SHOULD
1146 reject the AUTHENTICATE command by sending a tagged NO response.
1147
1148 The authentication protocol exchange consists of a series of
1149 server challenges and client answers that are specific to the
1150 authentication mechanism. A server challenge consists of a
1151 command continuation request response with the "+" token followed
1152 by a BASE64 encoded string. The client answer consists of a line
1153 consisting of a BASE64 encoded string. If the client wishes to
1154 cancel an authentication exchange, it issues a line with a single
1155 "*". If the server receives such an answer, it MUST reject the
1156 AUTHENTICATE command by sending a tagged BAD response.
1157
1158 A protection mechanism provides integrity and privacy protection
1159 to the connection. If a protection mechanism is negotiated, it is
1160 applied to all subsequent data sent over the connection. The
1161 protection mechanism takes effect immediately following the CRLF
1162 that concludes the authentication exchange for the client, and the
1163 CRLF of the tagged OK response for the server. Once the
1164 protection mechanism is in effect, the stream of command and
1165 response octets is processed into buffers of ciphertext. Each
1166 buffer is transferred over the connection as a stream of octets
1167 prepended with a four octet field in network byte order that
1168 represents the length of the following data. The maximum
1169 ciphertext buffer length is defined by the protection mechanism.
1170
1171 Authentication mechanisms are OPTIONAL. Protection mechanisms are
1172 also OPTIONAL; an authentication mechanism MAY be implemented
1173 without any protection mechanism. If an AUTHENTICATE command
1174 fails with a NO response, the client MAY try another
1175
1176
1177
1178Crispin Standards Track [Page 21]
1179
1180RFC 2060 IMAP4rev1 December 1996
1181
1182
1183 authentication mechanism by issuing another AUTHENTICATE command,
1184 or MAY attempt to authenticate by using the LOGIN command. In
1185 other words, the client MAY request authentication types in
1186 decreasing order of preference, with the LOGIN command as a last
1187 resort.
1188
1189 Example: S: * OK KerberosV4 IMAP4rev1 Server
1190 C: A001 AUTHENTICATE KERBEROS_V4
1191 S: + AmFYig==
1192 C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
1193 +nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd
1194 WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh
1195 S: + or//EoAADZI=
1196 C: DiAF5A4gA+oOIALuBkAAmw==
1197 S: A001 OK Kerberos V4 authentication successful
1198
1199 Note: the line breaks in the first client answer are for editorial
1200 clarity and are not in real authenticators.
1201
12026.2.2. LOGIN Command
1203
1204 Arguments: user name
1205 password
1206
1207 Responses: no specific responses for this command
1208
1209 Result: OK - login completed, now in authenticated state
1210 NO - login failure: user name or password rejected
1211 BAD - command unknown or arguments invalid
1212
1213 The LOGIN command identifies the client to the server and carries
1214 the plaintext password authenticating this user.
1215
1216 Example: C: a001 LOGIN SMITH SESAME
1217 S: a001 OK LOGIN completed
1218
12196.3. Client Commands - Authenticated State
1220
1221 In authenticated state, commands that manipulate mailboxes as atomic
1222 entities are permitted. Of these commands, the SELECT and EXAMINE
1223 commands will select a mailbox for access and enter selected state.
1224
1225 In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
1226 the following commands are valid in authenticated state: SELECT,
1227 EXAMINE, CREATE, DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, LSUB,
1228 STATUS, and APPEND.
1229
1230
1231
1232
1233
1234Crispin Standards Track [Page 22]
1235
1236RFC 2060 IMAP4rev1 December 1996
1237
1238
12396.3.1. SELECT Command
1240
1241 Arguments: mailbox name
1242
1243 Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT
1244 OPTIONAL OK untagged responses: UNSEEN, PERMANENTFLAGS
1245
1246 Result: OK - select completed, now in selected state
1247 NO - select failure, now in authenticated state: no
1248 such mailbox, can't access mailbox
1249 BAD - command unknown or arguments invalid
1250
1251 The SELECT command selects a mailbox so that messages in the
1252 mailbox can be accessed. Before returning an OK to the client,
1253 the server MUST send the following untagged data to the client:
1254
1255 FLAGS Defined flags in the mailbox. See the description
1256 of the FLAGS response for more detail.
1257
1258 <n> EXISTS The number of messages in the mailbox. See the
1259 description of the EXISTS response for more detail.
1260
1261 <n> RECENT The number of messages with the \Recent flag set.
1262 See the description of the RECENT response for more
1263 detail.
1264
1265 OK [UIDVALIDITY <n>]
1266 The unique identifier validity value. See the
1267 description of the UID command for more detail.
1268
1269 to define the initial state of the mailbox at the client.
1270
1271 The server SHOULD also send an UNSEEN response code in an OK
1272 untagged response, indicating the message sequence number of the
1273 first unseen message in the mailbox.
1274
1275 If the client can not change the permanent state of one or more of
1276 the flags listed in the FLAGS untagged response, the server SHOULD
1277 send a PERMANENTFLAGS response code in an OK untagged response,
1278 listing the flags that the client can change permanently.
1279
1280 Only one mailbox can be selected at a time in a connection;
1281 simultaneous access to multiple mailboxes requires multiple
1282 connections. The SELECT command automatically deselects any
1283 currently selected mailbox before attempting the new selection.
1284 Consequently, if a mailbox is selected and a SELECT command that
1285 fails is attempted, no mailbox is selected.
1286
1287
1288
1289
1290Crispin Standards Track [Page 23]
1291
1292RFC 2060 IMAP4rev1 December 1996
1293
1294
1295 If the client is permitted to modify the mailbox, the server
1296 SHOULD prefix the text of the tagged OK response with the
1297 "[READ-WRITE]" response code.
1298
1299 If the client is not permitted to modify the mailbox but is
1300 permitted read access, the mailbox is selected as read-only, and
1301 the server MUST prefix the text of the tagged OK response to
1302 SELECT with the "[READ-ONLY]" response code. Read-only access
1303 through SELECT differs from the EXAMINE command in that certain
1304 read-only mailboxes MAY permit the change of permanent state on a
1305 per-user (as opposed to global) basis. Netnews messages marked in
1306 a server-based .newsrc file are an example of such per-user
1307 permanent state that can be modified with read-only mailboxes.
1308
1309 Example: C: A142 SELECT INBOX
1310 S: * 172 EXISTS
1311 S: * 1 RECENT
1312 S: * OK [UNSEEN 12] Message 12 is first unseen
1313 S: * OK [UIDVALIDITY 3857529045] UIDs valid
1314 S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
1315 S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
1316 S: A142 OK [READ-WRITE] SELECT completed
1317
13186.3.2. EXAMINE Command
1319
1320 Arguments: mailbox name
1321
1322 Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT
1323 OPTIONAL OK untagged responses: UNSEEN, PERMANENTFLAGS
1324
1325 Result: OK - examine completed, now in selected state
1326 NO - examine failure, now in authenticated state: no
1327 such mailbox, can't access mailbox
1328 BAD - command unknown or arguments invalid
1329
1330 The EXAMINE command is identical to SELECT and returns the same
1331 output; however, the selected mailbox is identified as read-only.
1332 No changes to the permanent state of the mailbox, including
1333 per-user state, are permitted.
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346Crispin Standards Track [Page 24]
1347
1348RFC 2060 IMAP4rev1 December 1996
1349
1350
1351 The text of the tagged OK response to the EXAMINE command MUST
1352 begin with the "[READ-ONLY]" response code.
1353
1354 Example: C: A932 EXAMINE blurdybloop
1355 S: * 17 EXISTS
1356 S: * 2 RECENT
1357 S: * OK [UNSEEN 8] Message 8 is first unseen
1358 S: * OK [UIDVALIDITY 3857529045] UIDs valid
1359 S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
1360 S: * OK [PERMANENTFLAGS ()] No permanent flags permitted
1361 S: A932 OK [READ-ONLY] EXAMINE completed
1362
13636.3.3. CREATE Command
1364
1365 Arguments: mailbox name
1366
1367 Responses: no specific responses for this command
1368
1369 Result: OK - create completed
1370 NO - create failure: can't create mailbox with that name
1371 BAD - command unknown or arguments invalid
1372
1373 The CREATE command creates a mailbox with the given name. An OK
1374 response is returned only if a new mailbox with that name has been
1375 created. It is an error to attempt to create INBOX or a mailbox
1376 with a name that refers to an extant mailbox. Any error in
1377 creation will return a tagged NO response.
1378
1379 If the mailbox name is suffixed with the server's hierarchy
1380 separator character (as returned from the server by a LIST
1381 command), this is a declaration that the client intends to create
1382 mailbox names under this name in the hierarchy. Server
1383 implementations that do not require this declaration MUST ignore
1384 it.
1385
1386 If the server's hierarchy separator character appears elsewhere in
1387 the name, the server SHOULD create any superior hierarchical names
1388 that are needed for the CREATE command to complete successfully.
1389 In other words, an attempt to create "foo/bar/zap" on a server in
1390 which "/" is the hierarchy separator character SHOULD create foo/
1391 and foo/bar/ if they do not already exist.
1392
1393 If a new mailbox is created with the same name as a mailbox which
1394 was deleted, its unique identifiers MUST be greater than any
1395 unique identifiers used in the previous incarnation of the mailbox
1396 UNLESS the new incarnation has a different unique identifier
1397 validity value. See the description of the UID command for more
1398 detail.
1399
1400
1401
1402Crispin Standards Track [Page 25]
1403
1404RFC 2060 IMAP4rev1 December 1996
1405
1406
1407 Example: C: A003 CREATE owatagusiam/
1408 S: A003 OK CREATE completed
1409 C: A004 CREATE owatagusiam/blurdybloop
1410 S: A004 OK CREATE completed
1411
1412 Note: the interpretation of this example depends on whether "/"
1413 was returned as the hierarchy separator from LIST. If "/" is the
1414 hierarchy separator, a new level of hierarchy named "owatagusiam"
1415 with a member called "blurdybloop" is created. Otherwise, two
1416 mailboxes at the same hierarchy level are created.
1417
14186.3.4. DELETE Command
1419
1420 Arguments: mailbox name
1421
1422 Responses: no specific responses for this command
1423
1424 Result: OK - delete completed
1425 NO - delete failure: can't delete mailbox with that name
1426 BAD - command unknown or arguments invalid
1427
1428 The DELETE command permanently removes the mailbox with the given
1429 name. A tagged OK response is returned only if the mailbox has
1430 been deleted. It is an error to attempt to delete INBOX or a
1431 mailbox name that does not exist.
1432
1433 The DELETE command MUST NOT remove inferior hierarchical names.
1434 For example, if a mailbox "foo" has an inferior "foo.bar"
1435 (assuming "." is the hierarchy delimiter character), removing
1436 "foo" MUST NOT remove "foo.bar". It is an error to attempt to
1437 delete a name that has inferior hierarchical names and also has
1438 the \Noselect mailbox name attribute (see the description of the
1439 LIST response for more details).
1440
1441 It is permitted to delete a name that has inferior hierarchical
1442 names and does not have the \Noselect mailbox name attribute. In
1443 this case, all messages in that mailbox are removed, and the name
1444 will acquire the \Noselect mailbox name attribute.
1445
1446 The value of the highest-used unique identifier of the deleted
1447 mailbox MUST be preserved so that a new mailbox created with the
1448 same name will not reuse the identifiers of the former
1449 incarnation, UNLESS the new incarnation has a different unique
1450 identifier validity value. See the description of the UID command
1451 for more detail.
1452
1453
1454
1455
1456
1457
1458Crispin Standards Track [Page 26]
1459
1460RFC 2060 IMAP4rev1 December 1996
1461
1462
1463 Examples: C: A682 LIST "" *
1464 S: * LIST () "/" blurdybloop
1465 S: * LIST (\Noselect) "/" foo
1466 S: * LIST () "/" foo/bar
1467 S: A682 OK LIST completed
1468 C: A683 DELETE blurdybloop
1469 S: A683 OK DELETE completed
1470 C: A684 DELETE foo
1471 S: A684 NO Name "foo" has inferior hierarchical names
1472 C: A685 DELETE foo/bar
1473 S: A685 OK DELETE Completed
1474 C: A686 LIST "" *
1475 S: * LIST (\Noselect) "/" foo
1476 S: A686 OK LIST completed
1477 C: A687 DELETE foo
1478 S: A687 OK DELETE Completed
1479
1480
1481 C: A82 LIST "" *
1482 S: * LIST () "." blurdybloop
1483 S: * LIST () "." foo
1484 S: * LIST () "." foo.bar
1485 S: A82 OK LIST completed
1486 C: A83 DELETE blurdybloop
1487 S: A83 OK DELETE completed
1488 C: A84 DELETE foo
1489 S: A84 OK DELETE Completed
1490 C: A85 LIST "" *
1491 S: * LIST () "." foo.bar
1492 S: A85 OK LIST completed
1493 C: A86 LIST "" %
1494 S: * LIST (\Noselect) "." foo
1495 S: A86 OK LIST completed
1496
14976.3.5. RENAME Command
1498
1499 Arguments: existing mailbox name
1500 new mailbox name
1501
1502 Responses: no specific responses for this command
1503
1504 Result: OK - rename completed
1505 NO - rename failure: can't rename mailbox with that name,
1506 can't rename to mailbox with that name
1507 BAD - command unknown or arguments invalid
1508
1509 The RENAME command changes the name of a mailbox. A tagged OK
1510 response is returned only if the mailbox has been renamed. It is
1511
1512
1513
1514Crispin Standards Track [Page 27]
1515
1516RFC 2060 IMAP4rev1 December 1996
1517
1518
1519 an error to attempt to rename from a mailbox name that does not
1520 exist or to a mailbox name that already exists. Any error in
1521 renaming will return a tagged NO response.
1522
1523 If the name has inferior hierarchical names, then the inferior
1524 hierarchical names MUST also be renamed. For example, a rename of
1525 "foo" to "zap" will rename "foo/bar" (assuming "/" is the
1526 hierarchy delimiter character) to "zap/bar".
1527
1528 The value of the highest-used unique identifier of the old mailbox
1529 name MUST be preserved so that a new mailbox created with the same
1530 name will not reuse the identifiers of the former incarnation,
1531 UNLESS the new incarnation has a different unique identifier
1532 validity value. See the description of the UID command for more
1533 detail.
1534
1535 Renaming INBOX is permitted, and has special behavior. It moves
1536 all messages in INBOX to a new mailbox with the given name,
1537 leaving INBOX empty. If the server implementation supports
1538 inferior hierarchical names of INBOX, these are unaffected by a
1539 rename of INBOX.
1540
1541 Examples: C: A682 LIST "" *
1542 S: * LIST () "/" blurdybloop
1543 S: * LIST (\Noselect) "/" foo
1544 S: * LIST () "/" foo/bar
1545 S: A682 OK LIST completed
1546 C: A683 RENAME blurdybloop sarasoop
1547 S: A683 OK RENAME completed
1548 C: A684 RENAME foo zowie
1549 S: A684 OK RENAME Completed
1550 C: A685 LIST "" *
1551 S: * LIST () "/" sarasoop
1552 S: * LIST (\Noselect) "/" zowie
1553 S: * LIST () "/" zowie/bar
1554 S: A685 OK LIST completed
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570Crispin Standards Track [Page 28]
1571
1572RFC 2060 IMAP4rev1 December 1996
1573
1574
1575 C: Z432 LIST "" *
1576 S: * LIST () "." INBOX
1577 S: * LIST () "." INBOX.bar
1578 S: Z432 OK LIST completed
1579 C: Z433 RENAME INBOX old-mail
1580 S: Z433 OK RENAME completed
1581 C: Z434 LIST "" *
1582 S: * LIST () "." INBOX
1583 S: * LIST () "." INBOX.bar
1584 S: * LIST () "." old-mail
1585 S: Z434 OK LIST completed
1586
15876.3.6. SUBSCRIBE Command
1588
1589 Arguments: mailbox
1590
1591 Responses: no specific responses for this command
1592
1593 Result: OK - subscribe completed
1594 NO - subscribe failure: can't subscribe to that name
1595 BAD - command unknown or arguments invalid
1596
1597 The SUBSCRIBE command adds the specified mailbox name to the
1598 server's set of "active" or "subscribed" mailboxes as returned by
1599 the LSUB command. This command returns a tagged OK response only
1600 if the subscription is successful.
1601
1602 A server MAY validate the mailbox argument to SUBSCRIBE to verify
1603 that it exists. However, it MUST NOT unilaterally remove an
1604 existing mailbox name from the subscription list even if a mailbox
1605 by that name no longer exists.
1606
1607 Note: this requirement is because some server sites may routinely
1608 remove a mailbox with a well-known name (e.g. "system-alerts")
1609 after its contents expire, with the intention of recreating it
1610 when new contents are appropriate.
1611
1612 Example: C: A002 SUBSCRIBE #news.comp.mail.mime
1613 S: A002 OK SUBSCRIBE completed
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626Crispin Standards Track [Page 29]
1627
1628RFC 2060 IMAP4rev1 December 1996
1629
1630
16316.3.7. UNSUBSCRIBE Command
1632
1633 Arguments: mailbox name
1634
1635 Responses: no specific responses for this command
1636
1637 Result: OK - unsubscribe completed
1638 NO - unsubscribe failure: can't unsubscribe that name
1639 BAD - command unknown or arguments invalid
1640
1641 The UNSUBSCRIBE command removes the specified mailbox name from
1642 the server's set of "active" or "subscribed" mailboxes as returned
1643 by the LSUB command. This command returns a tagged OK response
1644 only if the unsubscription is successful.
1645
1646 Example: C: A002 UNSUBSCRIBE #news.comp.mail.mime
1647 S: A002 OK UNSUBSCRIBE completed
1648
16496.3..8. LIST Command
1650
1651 Arguments: reference name
1652 mailbox name with possible wildcards
1653
1654 Responses: untagged responses: LIST
1655
1656 Result: OK - list completed
1657 NO - list failure: can't list that reference or name
1658 BAD - command unknown or arguments invalid
1659
1660 The LIST command returns a subset of names from the complete set
1661 of all names available to the client. Zero or more untagged LIST
1662 replies are returned, containing the name attributes, hierarchy
1663 delimiter, and name; see the description of the LIST reply for
1664 more detail.
1665
1666 The LIST command SHOULD return its data quickly, without undue
1667 delay. For example, it SHOULD NOT go to excess trouble to
1668 calculate \Marked or \Unmarked status or perform other processing;
1669 if each name requires 1 second of processing, then a list of 1200
1670 names would take 20 minutes!
1671
1672 An empty ("" string) reference name argument indicates that the
1673 mailbox name is interpreted as by SELECT. The returned mailbox
1674 names MUST match the supplied mailbox name pattern. A non-empty
1675 reference name argument is the name of a mailbox or a level of
1676 mailbox hierarchy, and indicates a context in which the mailbox
1677 name is interpreted in an implementation-defined manner.
1678
1679
1680
1681
1682Crispin Standards Track [Page 30]
1683
1684RFC 2060 IMAP4rev1 December 1996
1685
1686
1687 An empty ("" string) mailbox name argument is a special request to
1688 return the hierarchy delimiter and the root name of the name given
1689 in the reference. The value returned as the root MAY be null if
1690 the reference is non-rooted or is null. In all cases, the
1691 hierarchy delimiter is returned. This permits a client to get the
1692 hierarchy delimiter even when no mailboxes by that name currently
1693 exist.
1694
1695 The reference and mailbox name arguments are interpreted, in an
1696 implementation-dependent fashion, into a canonical form that
1697 represents an unambiguous left-to-right hierarchy. The returned
1698 mailbox names will be in the interpreted form.
1699
1700 Any part of the reference argument that is included in the
1701 interpreted form SHOULD prefix the interpreted form. It SHOULD
1702 also be in the same form as the reference name argument. This
1703 rule permits the client to determine if the returned mailbox name
1704 is in the context of the reference argument, or if something about
1705 the mailbox argument overrode the reference argument. Without
1706 this rule, the client would have to have knowledge of the server's
1707 naming semantics including what characters are "breakouts" that
1708 override a naming context.
1709
1710 For example, here are some examples of how references and mailbox
1711 names might be interpreted on a UNIX-based server:
1712
1713 Reference Mailbox Name Interpretation
1714 ------------ ------------ --------------
1715 ~smith/Mail/ foo.* ~smith/Mail/foo.*
1716 archive/ % archive/%
1717 #news. comp.mail.* #news.comp.mail.*
1718 ~smith/Mail/ /usr/doc/foo /usr/doc/foo
1719 archive/ ~fred/Mail/* ~fred/Mail/*
1720
1721 The first three examples demonstrate interpretations in the
1722 context of the reference argument. Note that "~smith/Mail" SHOULD
1723 NOT be transformed into something like "/u2/users/smith/Mail", or
1724 it would be impossible for the client to determine that the
1725 interpretation was in the context of the reference.
1726
1727 The character "*" is a wildcard, and matches zero or more
1728 characters at this position. The character "%" is similar to "*",
1729 but it does not match a hierarchy delimiter. If the "%" wildcard
1730 is the last character of a mailbox name argument, matching levels
1731 of hierarchy are also returned. If these levels of hierarchy are
1732 not also selectable mailboxes, they are returned with the
1733 \Noselect mailbox name attribute (see the description of the LIST
1734 response for more details).
1735
1736
1737
1738Crispin Standards Track [Page 31]
1739
1740RFC 2060 IMAP4rev1 December 1996
1741
1742
1743 Server implementations are permitted to "hide" otherwise
1744 accessible mailboxes from the wildcard characters, by preventing
1745 certain characters or names from matching a wildcard in certain
1746 situations. For example, a UNIX-based server might restrict the
1747 interpretation of "*" so that an initial "/" character does not
1748 match.
1749
1750 The special name INBOX is included in the output from LIST, if
1751 INBOX is supported by this server for this user and if the
1752 uppercase string "INBOX" matches the interpreted reference and
1753 mailbox name arguments with wildcards as described above. The
1754 criteria for omitting INBOX is whether SELECT INBOX will return
1755 failure; it is not relevant whether the user's real INBOX resides
1756 on this or some other server.
1757
1758 Example: C: A101 LIST "" ""
1759 S: * LIST (\Noselect) "/" ""
1760 S: A101 OK LIST Completed
1761 C: A102 LIST #news.comp.mail.misc ""
1762 S: * LIST (\Noselect) "." #news.
1763 S: A102 OK LIST Completed
1764 C: A103 LIST /usr/staff/jones ""
1765 S: * LIST (\Noselect) "/" /
1766 S: A103 OK LIST Completed
1767 C: A202 LIST ~/Mail/ %
1768 S: * LIST (\Noselect) "/" ~/Mail/foo
1769 S: * LIST () "/" ~/Mail/meetings
1770 S: A202 OK LIST completed
1771
17726.3.9. LSUB Command
1773
1774 Arguments: reference name
1775 mailbox name with possible wildcards
1776
1777 Responses: untagged responses: LSUB
1778
1779 Result: OK - lsub completed
1780 NO - lsub failure: can't list that reference or name
1781 BAD - command unknown or arguments invalid
1782
1783 The LSUB command returns a subset of names from the set of names
1784 that the user has declared as being "active" or "subscribed".
1785 Zero or more untagged LSUB replies are returned. The arguments to
1786 LSUB are in the same form as those for LIST.
1787
1788 A server MAY validate the subscribed names to see if they still
1789 exist. If a name does not exist, it SHOULD be flagged with the
1790 \Noselect attribute in the LSUB response. The server MUST NOT
1791
1792
1793
1794Crispin Standards Track [Page 32]
1795
1796RFC 2060 IMAP4rev1 December 1996
1797
1798
1799 unilaterally remove an existing mailbox name from the subscription
1800 list even if a mailbox by that name no longer exists.
1801
1802 Example: C: A002 LSUB "#news." "comp.mail.*"
1803 S: * LSUB () "." #news.comp.mail.mime
1804 S: * LSUB () "." #news.comp.mail.misc
1805 S: A002 OK LSUB completed
1806
18076.3.10. STATUS Command
1808
1809 Arguments: mailbox name
1810 status data item names
1811
1812 Responses: untagged responses: STATUS
1813
1814 Result: OK - status completed
1815 NO - status failure: no status for that name
1816 BAD - command unknown or arguments invalid
1817
1818 The STATUS command requests the status of the indicated mailbox.
1819 It does not change the currently selected mailbox, nor does it
1820 affect the state of any messages in the queried mailbox (in
1821 particular, STATUS MUST NOT cause messages to lose the \Recent
1822 flag).
1823
1824 The STATUS command provides an alternative to opening a second
1825 IMAP4rev1 connection and doing an EXAMINE command on a mailbox to
1826 query that mailbox's status without deselecting the current
1827 mailbox in the first IMAP4rev1 connection.
1828
1829 Unlike the LIST command, the STATUS command is not guaranteed to
1830 be fast in its response. In some implementations, the server is
1831 obliged to open the mailbox read-only internally to obtain certain
1832 status information. Also unlike the LIST command, the STATUS
1833 command does not accept wildcards.
1834
1835 The currently defined status data items that can be requested are:
1836
1837 MESSAGES The number of messages in the mailbox.
1838
1839 RECENT The number of messages with the \Recent flag set.
1840
1841 UIDNEXT The next UID value that will be assigned to a new
1842 message in the mailbox. It is guaranteed that this
1843 value will not change unless new messages are added
1844 to the mailbox; and that it will change when new
1845 messages are added even if those new messages are
1846 subsequently expunged.
1847
1848
1849
1850Crispin Standards Track [Page 33]
1851
1852RFC 2060 IMAP4rev1 December 1996
1853
1854
1855 UIDVALIDITY The unique identifier validity value of the
1856 mailbox.
1857
1858 UNSEEN The number of messages which do not have the \Seen
1859 flag set.
1860
1861
1862 Example: C: A042 STATUS blurdybloop (UIDNEXT MESSAGES)
1863 S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
1864 S: A042 OK STATUS completed
1865
18666.3.11. APPEND Command
1867
1868 Arguments: mailbox name
1869 OPTIONAL flag parenthesized list
1870 OPTIONAL date/time string
1871 message literal
1872
1873 Responses: no specific responses for this command
1874
1875 Result: OK - append completed
1876 NO - append error: can't append to that mailbox, error
1877 in flags or date/time or message text
1878 BAD - command unknown or arguments invalid
1879
1880 The APPEND command appends the literal argument as a new message
1881 to the end of the specified destination mailbox. This argument
1882 SHOULD be in the format of an [RFC-822] message. 8-bit characters
1883 are permitted in the message. A server implementation that is
1884 unable to preserve 8-bit data properly MUST be able to reversibly
1885 convert 8-bit APPEND data to 7-bit using a [MIME-IMB] content
1886 transfer encoding.
1887
1888 Note: There MAY be exceptions, e.g. draft messages, in which
1889 required [RFC-822] header lines are omitted in the message literal
1890 argument to APPEND. The full implications of doing so MUST be
1891 understood and carefully weighed.
1892
1893 If a flag parenthesized list is specified, the flags SHOULD be set in
1894 the resulting message; otherwise, the flag list of the resulting
1895 message is set empty by default.
1896
1897 If a date_time is specified, the internal date SHOULD be set in the
1898 resulting message; otherwise, the internal date of the resulting
1899 message is set to the current date and time by default.
1900
1901
1902
1903
1904
1905
1906Crispin Standards Track [Page 34]
1907
1908RFC 2060 IMAP4rev1 December 1996
1909
1910
1911 If the append is unsuccessful for any reason, the mailbox MUST be
1912 restored to its state before the APPEND attempt; no partial appending
1913 is permitted.
1914
1915 If the destination mailbox does not exist, a server MUST return an
1916 error, and MUST NOT automatically create the mailbox. Unless it is
1917 certain that the destination mailbox can not be created, the server
1918 MUST send the response code "[TRYCREATE]" as the prefix of the text
1919 of the tagged NO response. This gives a hint to the client that it
1920 can attempt a CREATE command and retry the APPEND if the CREATE is
1921 successful.
1922
1923 If the mailbox is currently selected, the normal new mail actions
1924 SHOULD occur. Specifically, the server SHOULD notify the client
1925 immediately via an untagged EXISTS response. If the server does not
1926 do so, the client MAY issue a NOOP command (or failing that, a CHECK
1927 command) after one or more APPEND commands.
1928
1929 Example: C: A003 APPEND saved-messages (\Seen) {310}
1930 C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
1931 C: From: Fred Foobar <foobar@Blurdybloop.COM>
1932 C: Subject: afternoon meeting
1933 C: To: mooch@owatagu.siam.edu
1934 C: Message-Id: <B27397-0100000@Blurdybloop.COM>
1935 C: MIME-Version: 1.0
1936 C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
1937 C:
1938 C: Hello Joe, do you think we can meet at 3:30 tomorrow?
1939 C:
1940 S: A003 OK APPEND completed
1941
1942 Note: the APPEND command is not used for message delivery, because
1943 it does not provide a mechanism to transfer [SMTP] envelope
1944 information.
1945
19466.4. Client Commands - Selected State
1947
1948 In selected state, commands that manipulate messages in a mailbox are
1949 permitted.
1950
1951 In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
1952 and the authenticated state commands (SELECT, EXAMINE, CREATE,
1953 DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, LSUB, STATUS, and
1954 APPEND), the following commands are valid in the selected state:
1955 CHECK, CLOSE, EXPUNGE, SEARCH, FETCH, STORE, COPY, and UID.
1956
1957
1958
1959
1960
1961
1962Crispin Standards Track [Page 35]
1963
1964RFC 2060 IMAP4rev1 December 1996
1965
1966
19676.4.1. CHECK Command
1968
1969 Arguments: none
1970
1971 Responses: no specific responses for this command
1972
1973 Result: OK - check completed
1974 BAD - command unknown or arguments invalid
1975
1976 The CHECK command requests a checkpoint of the currently selected
1977 mailbox. A checkpoint refers to any implementation-dependent
1978 housekeeping associated with the mailbox (e.g. resolving the
1979 server's in-memory state of the mailbox with the state on its
1980 disk) that is not normally executed as part of each command. A
1981 checkpoint MAY take a non-instantaneous amount of real time to
1982 complete. If a server implementation has no such housekeeping
1983 considerations, CHECK is equivalent to NOOP.
1984
1985 There is no guarantee that an EXISTS untagged response will happen
1986 as a result of CHECK. NOOP, not CHECK, SHOULD be used for new
1987 mail polling.
1988
1989 Example: C: FXXZ CHECK
1990 S: FXXZ OK CHECK Completed
1991
19926.4.2. CLOSE Command
1993
1994 Arguments: none
1995
1996 Responses: no specific responses for this command
1997
1998 Result: OK - close completed, now in authenticated state
1999 NO - close failure: no mailbox selected
2000 BAD - command unknown or arguments invalid
2001
2002 The CLOSE command permanently removes from the currently selected
2003 mailbox all messages that have the \Deleted flag set, and returns
2004 to authenticated state from selected state. No untagged EXPUNGE
2005 responses are sent.
2006
2007 No messages are removed, and no error is given, if the mailbox is
2008 selected by an EXAMINE command or is otherwise selected read-only.
2009
2010 Even if a mailbox is selected, a SELECT, EXAMINE, or LOGOUT
2011 command MAY be issued without previously issuing a CLOSE command.
2012 The SELECT, EXAMINE, and LOGOUT commands implicitly close the
2013 currently selected mailbox without doing an expunge. However,
2014 when many messages are deleted, a CLOSE-LOGOUT or CLOSE-SELECT
2015
2016
2017
2018Crispin Standards Track [Page 36]
2019
2020RFC 2060 IMAP4rev1 December 1996
2021
2022
2023 sequence is considerably faster than an EXPUNGE-LOGOUT or
2024 EXPUNGE-SELECT because no untagged EXPUNGE responses (which the
2025 client would probably ignore) are sent.
2026
2027 Example: C: A341 CLOSE
2028 S: A341 OK CLOSE completed
2029
20306.4.3. EXPUNGE Command
2031
2032 Arguments: none
2033
2034 Responses: untagged responses: EXPUNGE
2035
2036 Result: OK - expunge completed
2037 NO - expunge failure: can't expunge (e.g. permission
2038 denied)
2039 BAD - command unknown or arguments invalid
2040
2041 The EXPUNGE command permanently removes from the currently
2042 selected mailbox all messages that have the \Deleted flag set.
2043 Before returning an OK to the client, an untagged EXPUNGE response
2044 is sent for each message that is removed.
2045
2046 Example: C: A202 EXPUNGE
2047 S: * 3 EXPUNGE
2048 S: * 3 EXPUNGE
2049 S: * 5 EXPUNGE
2050 S: * 8 EXPUNGE
2051 S: A202 OK EXPUNGE completed
2052
2053 Note: in this example, messages 3, 4, 7, and 11 had the
2054 \Deleted flag set. See the description of the EXPUNGE
2055 response for further explanation.
2056
20576.4.4. SEARCH Command
2058
2059 Arguments: OPTIONAL [CHARSET] specification
2060 searching criteria (one or more)
2061
2062 Responses: REQUIRED untagged response: SEARCH
2063
2064 Result: OK - search completed
2065 NO - search error: can't search that [CHARSET] or
2066 criteria
2067 BAD - command unknown or arguments invalid
2068
2069
2070
2071
2072
2073
2074Crispin Standards Track [Page 37]
2075
2076RFC 2060 IMAP4rev1 December 1996
2077
2078
2079 The SEARCH command searches the mailbox for messages that match
2080 the given searching criteria. Searching criteria consist of one
2081 or more search keys. The untagged SEARCH response from the server
2082 contains a listing of message sequence numbers corresponding to
2083 those messages that match the searching criteria.
2084
2085 When multiple keys are specified, the result is the intersection
2086 (AND function) of all the messages that match those keys. For
2087 example, the criteria DELETED FROM "SMITH" SINCE 1-Feb-1994 refers
2088 to all deleted messages from Smith that were placed in the mailbox
2089 since February 1, 1994. A search key can also be a parenthesized
2090 list of one or more search keys (e.g. for use with the OR and NOT
2091 keys).
2092
2093 Server implementations MAY exclude [MIME-IMB] body parts with
2094 terminal content media types other than TEXT and MESSAGE from
2095 consideration in SEARCH matching.
2096
2097 The OPTIONAL [CHARSET] specification consists of the word
2098 "CHARSET" followed by a registered [CHARSET]. It indicates the
2099 [CHARSET] of the strings that appear in the search criteria.
2100 [MIME-IMB] content transfer encodings, and [MIME-HDRS] strings in
2101 [RFC-822]/[MIME-IMB] headers, MUST be decoded before comparing
2102 text in a [CHARSET] other than US-ASCII. US-ASCII MUST be
2103 supported; other [CHARSET]s MAY be supported. If the server does
2104 not support the specified [CHARSET], it MUST return a tagged NO
2105 response (not a BAD).
2106
2107 In all search keys that use strings, a message matches the key if
2108 the string is a substring of the field. The matching is case-
2109 insensitive.
2110
2111 The defined search keys are as follows. Refer to the Formal
2112 Syntax section for the precise syntactic definitions of the
2113 arguments.
2114
2115 <message set> Messages with message sequence numbers
2116 corresponding to the specified message sequence
2117 number set
2118
2119 ALL All messages in the mailbox; the default initial
2120 key for ANDing.
2121
2122 ANSWERED Messages with the \Answered flag set.
2123
2124 BCC <string> Messages that contain the specified string in the
2125 envelope structure's BCC field.
2126
2127
2128
2129
2130Crispin Standards Track [Page 38]
2131
2132RFC 2060 IMAP4rev1 December 1996
2133
2134
2135 BEFORE <date> Messages whose internal date is earlier than the
2136 specified date.
2137
2138 BODY <string> Messages that contain the specified string in the
2139 body of the message.
2140
2141 CC <string> Messages that contain the specified string in the
2142 envelope structure's CC field.
2143
2144 DELETED Messages with the \Deleted flag set.
2145
2146 DRAFT Messages with the \Draft flag set.
2147
2148 FLAGGED Messages with the \Flagged flag set.
2149
2150 FROM <string> Messages that contain the specified string in the
2151 envelope structure's FROM field.
2152
2153 HEADER <field-name> <string>
2154 Messages that have a header with the specified
2155 field-name (as defined in [RFC-822]) and that
2156 contains the specified string in the [RFC-822]
2157 field-body.
2158
2159 KEYWORD <flag> Messages with the specified keyword set.
2160
2161 LARGER <n> Messages with an [RFC-822] size larger than the
2162 specified number of octets.
2163
2164 NEW Messages that have the \Recent flag set but not the
2165 \Seen flag. This is functionally equivalent to
2166 "(RECENT UNSEEN)".
2167
2168 NOT <search-key>
2169 Messages that do not match the specified search
2170 key.
2171
2172 OLD Messages that do not have the \Recent flag set.
2173 This is functionally equivalent to "NOT RECENT" (as
2174 opposed to "NOT NEW").
2175
2176 ON <date> Messages whose internal date is within the
2177 specified date.
2178
2179 OR <search-key1> <search-key2>
2180 Messages that match either search key.
2181
2182 RECENT Messages that have the \Recent flag set.
2183
2184
2185
2186Crispin Standards Track [Page 39]
2187
2188RFC 2060 IMAP4rev1 December 1996
2189
2190
2191 SEEN Messages that have the \Seen flag set.
2192
2193 SENTBEFORE <date>
2194 Messages whose [RFC-822] Date: header is earlier
2195 than the specified date.
2196
2197 SENTON <date> Messages whose [RFC-822] Date: header is within the
2198 specified date.
2199
2200 SENTSINCE <date>
2201 Messages whose [RFC-822] Date: header is within or
2202 later than the specified date.
2203
2204 SINCE <date> Messages whose internal date is within or later
2205 than the specified date.
2206
2207 SMALLER <n> Messages with an [RFC-822] size smaller than the
2208 specified number of octets.
2209
2210 SUBJECT <string>
2211 Messages that contain the specified string in the
2212 envelope structure's SUBJECT field.
2213
2214 TEXT <string> Messages that contain the specified string in the
2215 header or body of the message.
2216
2217 TO <string> Messages that contain the specified string in the
2218 envelope structure's TO field.
2219
2220 UID <message set>
2221 Messages with unique identifiers corresponding to
2222 the specified unique identifier set.
2223
2224 UNANSWERED Messages that do not have the \Answered flag set.
2225
2226 UNDELETED Messages that do not have the \Deleted flag set.
2227
2228 UNDRAFT Messages that do not have the \Draft flag set.
2229
2230 UNFLAGGED Messages that do not have the \Flagged flag set.
2231
2232 UNKEYWORD <flag>
2233 Messages that do not have the specified keyword
2234 set.
2235
2236 UNSEEN Messages that do not have the \Seen flag set.
2237
2238
2239
2240
2241
2242Crispin Standards Track [Page 40]
2243
2244RFC 2060 IMAP4rev1 December 1996
2245
2246
2247 Example: C: A282 SEARCH FLAGGED SINCE 1-Feb-1994 NOT FROM "Smith"
2248 S: * SEARCH 2 84 882
2249 S: A282 OK SEARCH completed
2250
22516.4.5. FETCH Command
2252
2253 Arguments: message set
2254 message data item names
2255
2256 Responses: untagged responses: FETCH
2257
2258 Result: OK - fetch completed
2259 NO - fetch error: can't fetch that data
2260 BAD - command unknown or arguments invalid
2261
2262 The FETCH command retrieves data associated with a message in the
2263 mailbox. The data items to be fetched can be either a single atom
2264 or a parenthesized list.
2265
2266 The currently defined data items that can be fetched are:
2267
2268 ALL Macro equivalent to: (FLAGS INTERNALDATE
2269 RFC822.SIZE ENVELOPE)
2270
2271 BODY Non-extensible form of BODYSTRUCTURE.
2272
2273 BODY[<section>]<<partial>>
2274 The text of a particular body section. The section
2275 specification is a set of zero or more part
2276 specifiers delimited by periods. A part specifier
2277 is either a part number or one of the following:
2278 HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, MIME, and
2279 TEXT. An empty section specification refers to the
2280 entire message, including the header.
2281
2282 Every message has at least one part number.
2283 Non-[MIME-IMB] messages, and non-multipart
2284 [MIME-IMB] messages with no encapsulated message,
2285 only have a part 1.
2286
2287 Multipart messages are assigned consecutive part
2288 numbers, as they occur in the message. If a
2289 particular part is of type message or multipart,
2290 its parts MUST be indicated by a period followed by
2291 the part number within that nested multipart part.
2292
2293
2294
2295
2296
2297
2298Crispin Standards Track [Page 41]
2299
2300RFC 2060 IMAP4rev1 December 1996
2301
2302
2303 A part of type MESSAGE/RFC822 also has nested part
2304 numbers, referring to parts of the MESSAGE part's
2305 body.
2306
2307 The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, and
2308 TEXT part specifiers can be the sole part specifier
2309 or can be prefixed by one or more numeric part
2310 specifiers, provided that the numeric part
2311 specifier refers to a part of type MESSAGE/RFC822.
2312 The MIME part specifier MUST be prefixed by one or
2313 more numeric part specifiers.
2314
2315 The HEADER, HEADER.FIELDS, and HEADER.FIELDS.NOT
2316 part specifiers refer to the [RFC-822] header of
2317 the message or of an encapsulated [MIME-IMT]
2318 MESSAGE/RFC822 message. HEADER.FIELDS and
2319 HEADER.FIELDS.NOT are followed by a list of
2320 field-name (as defined in [RFC-822]) names, and
2321 return a subset of the header. The subset returned
2322 by HEADER.FIELDS contains only those header fields
2323 with a field-name that matches one of the names in
2324 the list; similarly, the subset returned by
2325 HEADER.FIELDS.NOT contains only the header fields
2326 with a non-matching field-name. The field-matching
2327 is case-insensitive but otherwise exact. In all
2328 cases, the delimiting blank line between the header
2329 and the body is always included.
2330
2331 The MIME part specifier refers to the [MIME-IMB]
2332 header for this part.
2333
2334 The TEXT part specifier refers to the text body of
2335 the message, omitting the [RFC-822] header.
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354Crispin Standards Track [Page 42]
2355
2356RFC 2060 IMAP4rev1 December 1996
2357
2358
2359 Here is an example of a complex message
2360 with some of its part specifiers:
2361
2362 HEADER ([RFC-822] header of the message)
2363 TEXT MULTIPART/MIXED
2364 1 TEXT/PLAIN
2365 2 APPLICATION/OCTET-STREAM
2366 3 MESSAGE/RFC822
2367 3.HEADER ([RFC-822] header of the message)
2368 3.TEXT ([RFC-822] text body of the message)
2369 3.1 TEXT/PLAIN
2370 3.2 APPLICATION/OCTET-STREAM
2371 4 MULTIPART/MIXED
2372 4.1 IMAGE/GIF
2373 4.1.MIME ([MIME-IMB] header for the IMAGE/GIF)
2374 4.2 MESSAGE/RFC822
2375 4.2.HEADER ([RFC-822] header of the message)
2376 4.2.TEXT ([RFC-822] text body of the message)
2377 4.2.1 TEXT/PLAIN
2378 4.2.2 MULTIPART/ALTERNATIVE
2379 4.2.2.1 TEXT/PLAIN
2380 4.2.2.2 TEXT/RICHTEXT
2381
2382
2383 It is possible to fetch a substring of the
2384 designated text. This is done by appending an open
2385 angle bracket ("<"), the octet position of the
2386 first desired octet, a period, the maximum number
2387 of octets desired, and a close angle bracket (">")
2388 to the part specifier. If the starting octet is
2389 beyond the end of the text, an empty string is
2390 returned.
2391
2392 Any partial fetch that attempts to read beyond the
2393 end of the text is truncated as appropriate. A
2394 partial fetch that starts at octet 0 is returned as
2395 a partial fetch, even if this truncation happened.
2396
2397 Note: this means that BODY[]<0.2048> of a
2398 1500-octet message will return BODY[]<0>
2399 with a literal of size 1500, not BODY[].
2400
2401 Note: a substring fetch of a
2402 HEADER.FIELDS or HEADER.FIELDS.NOT part
2403 specifier is calculated after subsetting
2404 the header.
2405
2406
2407
2408
2409
2410Crispin Standards Track [Page 43]
2411
2412RFC 2060 IMAP4rev1 December 1996
2413
2414
2415 The \Seen flag is implicitly set; if this causes
2416 the flags to change they SHOULD be included as part
2417 of the FETCH responses.
2418
2419 BODY.PEEK[<section>]<<partial>>
2420 An alternate form of BODY[<section>] that does not
2421 implicitly set the \Seen flag.
2422
2423 BODYSTRUCTURE The [MIME-IMB] body structure of the message. This
2424 is computed by the server by parsing the [MIME-IMB]
2425 header fields in the [RFC-822] header and
2426 [MIME-IMB] headers.
2427
2428 ENVELOPE The envelope structure of the message. This is
2429 computed by the server by parsing the [RFC-822]
2430 header into the component parts, defaulting various
2431 fields as necessary.
2432
2433 FAST Macro equivalent to: (FLAGS INTERNALDATE
2434 RFC822.SIZE)
2435
2436 FLAGS The flags that are set for this message.
2437
2438 FULL Macro equivalent to: (FLAGS INTERNALDATE
2439 RFC822.SIZE ENVELOPE BODY)
2440
2441 INTERNALDATE The internal date of the message.
2442
2443 RFC822 Functionally equivalent to BODY[], differing in the
2444 syntax of the resulting untagged FETCH data (RFC822
2445 is returned).
2446
2447 RFC822.HEADER Functionally equivalent to BODY.PEEK[HEADER],
2448 differing in the syntax of the resulting untagged
2449 FETCH data (RFC822.HEADER is returned).
2450
2451 RFC822.SIZE The [RFC-822] size of the message.
2452
2453 RFC822.TEXT Functionally equivalent to BODY[TEXT], differing in
2454 the syntax of the resulting untagged FETCH data
2455 (RFC822.TEXT is returned).
2456
2457 UID The unique identifier for the message.
2458
2459
2460
2461
2462
2463
2464
2465
2466Crispin Standards Track [Page 44]
2467
2468RFC 2060 IMAP4rev1 December 1996
2469
2470
2471 Example: C: A654 FETCH 2:4 (FLAGS BODY[HEADER.FIELDS (DATE FROM)])
2472 S: * 2 FETCH ....
2473 S: * 3 FETCH ....
2474 S: * 4 FETCH ....
2475 S: A654 OK FETCH completed
2476
24776.4.6. STORE Command
2478
2479 Arguments: message set
2480 message data item name
2481 value for message data item
2482
2483 Responses: untagged responses: FETCH
2484
2485 Result: OK - store completed
2486 NO - store error: can't store that data
2487 BAD - command unknown or arguments invalid
2488
2489 The STORE command alters data associated with a message in the
2490 mailbox. Normally, STORE will return the updated value of the
2491 data with an untagged FETCH response. A suffix of ".SILENT" in
2492 the data item name prevents the untagged FETCH, and the server
2493 SHOULD assume that the client has determined the updated value
2494 itself or does not care about the updated value.
2495
2496 Note: regardless of whether or not the ".SILENT" suffix was
2497 used, the server SHOULD send an untagged FETCH response if a
2498 change to a message's flags from an external source is
2499 observed. The intent is that the status of the flags is
2500 determinate without a race condition.
2501
2502 The currently defined data items that can be stored are:
2503
2504 FLAGS <flag list>
2505 Replace the flags for the message with the
2506 argument. The new value of the flags are returned
2507 as if a FETCH of those flags was done.
2508
2509 FLAGS.SILENT <flag list>
2510 Equivalent to FLAGS, but without returning a new
2511 value.
2512
2513 +FLAGS <flag list>
2514 Add the argument to the flags for the message. The
2515 new value of the flags are returned as if a FETCH
2516 of those flags was done.
2517
2518
2519
2520
2521
2522Crispin Standards Track [Page 45]
2523
2524RFC 2060 IMAP4rev1 December 1996
2525
2526
2527 +FLAGS.SILENT <flag list>
2528 Equivalent to +FLAGS, but without returning a new
2529 value.
2530
2531 -FLAGS <flag list>
2532 Remove the argument from the flags for the message.
2533 The new value of the flags are returned as if a
2534 FETCH of those flags was done.
2535
2536 -FLAGS.SILENT <flag list>
2537 Equivalent to -FLAGS, but without returning a new
2538 value.
2539
2540 Example: C: A003 STORE 2:4 +FLAGS (\Deleted)
2541 S: * 2 FETCH FLAGS (\Deleted \Seen)
2542 S: * 3 FETCH FLAGS (\Deleted)
2543 S: * 4 FETCH FLAGS (\Deleted \Flagged \Seen)
2544 S: A003 OK STORE completed
2545
25466.4.7. COPY Command
2547
2548 Arguments: message set
2549 mailbox name
2550
2551 Responses: no specific responses for this command
2552
2553 Result: OK - copy completed
2554 NO - copy error: can't copy those messages or to that
2555 name
2556 BAD - command unknown or arguments invalid
2557
2558 The COPY command copies the specified message(s) to the end of the
2559 specified destination mailbox. The flags and internal date of the
2560 message(s) SHOULD be preserved in the copy.
2561
2562 If the destination mailbox does not exist, a server SHOULD return
2563 an error. It SHOULD NOT automatically create the mailbox. Unless
2564 it is certain that the destination mailbox can not be created, the
2565 server MUST send the response code "[TRYCREATE]" as the prefix of
2566 the text of the tagged NO response. This gives a hint to the
2567 client that it can attempt a CREATE command and retry the COPY if
2568 the CREATE is successful.
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578Crispin Standards Track [Page 46]
2579
2580RFC 2060 IMAP4rev1 December 1996
2581
2582
2583 If the COPY command is unsuccessful for any reason, server
2584 implementations MUST restore the destination mailbox to its state
2585 before the COPY attempt.
2586
2587 Example: C: A003 COPY 2:4 MEETING
2588 S: A003 OK COPY completed
2589
25906.4.8. UID Command
2591
2592 Arguments: command name
2593 command arguments
2594
2595 Responses: untagged responses: FETCH, SEARCH
2596
2597 Result: OK - UID command completed
2598 NO - UID command error
2599 BAD - command unknown or arguments invalid
2600
2601 The UID command has two forms. In the first form, it takes as its
2602 arguments a COPY, FETCH, or STORE command with arguments
2603 appropriate for the associated command. However, the numbers in
2604 the message set argument are unique identifiers instead of message
2605 sequence numbers.
2606
2607 In the second form, the UID command takes a SEARCH command with
2608 SEARCH command arguments. The interpretation of the arguments is
2609 the same as with SEARCH; however, the numbers returned in a SEARCH
2610 response for a UID SEARCH command are unique identifiers instead
2611 of message sequence numbers. For example, the command UID SEARCH
2612 1:100 UID 443:557 returns the unique identifiers corresponding to
2613 the intersection of the message sequence number set 1:100 and the
2614 UID set 443:557.
2615
2616 Message set ranges are permitted; however, there is no guarantee
2617 that unique identifiers be contiguous. A non-existent unique
2618 identifier within a message set range is ignored without any error
2619 message generated.
2620
2621 The number after the "*" in an untagged FETCH response is always a
2622 message sequence number, not a unique identifier, even for a UID
2623 command response. However, server implementations MUST implicitly
2624 include the UID message data item as part of any FETCH response
2625 caused by a UID command, regardless of whether a UID was specified
2626 as a message data item to the FETCH.
2627
2628
2629
2630
2631
2632
2633
2634Crispin Standards Track [Page 47]
2635
2636RFC 2060 IMAP4rev1 December 1996
2637
2638
2639 Example: C: A999 UID FETCH 4827313:4828442 FLAGS
2640 S: * 23 FETCH (FLAGS (\Seen) UID 4827313)
2641 S: * 24 FETCH (FLAGS (\Seen) UID 4827943)
2642 S: * 25 FETCH (FLAGS (\Seen) UID 4828442)
2643 S: A999 UID FETCH completed
2644
26456.5. Client Commands - Experimental/Expansion
2646
26476.5.1. X<atom> Command
2648
2649 Arguments: implementation defined
2650
2651 Responses: implementation defined
2652
2653 Result: OK - command completed
2654 NO - failure
2655 BAD - command unknown or arguments invalid
2656
2657 Any command prefixed with an X is an experimental command.
2658 Commands which are not part of this specification, a standard or
2659 standards-track revision of this specification, or an IESG-
2660 approved experimental protocol, MUST use the X prefix.
2661
2662 Any added untagged responses issued by an experimental command
2663 MUST also be prefixed with an X. Server implementations MUST NOT
2664 send any such untagged responses, unless the client requested it
2665 by issuing the associated experimental command.
2666
2667 Example: C: a441 CAPABILITY
2668 S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4 XPIG-LATIN
2669 S: a441 OK CAPABILITY completed
2670 C: A442 XPIG-LATIN
2671 S: * XPIG-LATIN ow-nay eaking-spay ig-pay atin-lay
2672 S: A442 OK XPIG-LATIN ompleted-cay
2673
26747. Server Responses
2675
2676 Server responses are in three forms: status responses, server data,
2677 and command continuation request. The information contained in a
2678 server response, identified by "Contents:" in the response
2679 descriptions below, is described by function, not by syntax. The
2680 precise syntax of server responses is described in the Formal Syntax
2681 section.
2682
2683 The client MUST be prepared to accept any response at all times.
2684
2685
2686
2687
2688
2689
2690Crispin Standards Track [Page 48]
2691
2692RFC 2060 IMAP4rev1 December 1996
2693
2694
2695 Status responses can be tagged or untagged. Tagged status responses
2696 indicate the completion result (OK, NO, or BAD status) of a client
2697 command, and have a tag matching the command.
2698
2699 Some status responses, and all server data, are untagged. An
2700 untagged response is indicated by the token "*" instead of a tag.
2701 Untagged status responses indicate server greeting, or server status
2702 that does not indicate the completion of a command (for example, an
2703 impending system shutdown alert). For historical reasons, untagged
2704 server data responses are also called "unsolicited data", although
2705 strictly speaking only unilateral server data is truly "unsolicited".
2706
2707 Certain server data MUST be recorded by the client when it is
2708 received; this is noted in the description of that data. Such data
2709 conveys critical information which affects the interpretation of all
2710 subsequent commands and responses (e.g. updates reflecting the
2711 creation or destruction of messages).
2712
2713 Other server data SHOULD be recorded for later reference; if the
2714 client does not need to record the data, or if recording the data has
2715 no obvious purpose (e.g. a SEARCH response when no SEARCH command is
2716 in progress), the data SHOULD be ignored.
2717
2718 An example of unilateral untagged server data occurs when the IMAP
2719 connection is in selected state. In selected state, the server
2720 checks the mailbox for new messages as part of command execution.
2721 Normally, this is part of the execution of every command; hence, a
2722 NOOP command suffices to check for new messages. If new messages are
2723 found, the server sends untagged EXISTS and RECENT responses
2724 reflecting the new size of the mailbox. Server implementations that
2725 offer multiple simultaneous access to the same mailbox SHOULD also
2726 send appropriate unilateral untagged FETCH and EXPUNGE responses if
2727 another agent changes the state of any message flags or expunges any
2728 messages.
2729
2730 Command continuation request responses use the token "+" instead of a
2731 tag. These responses are sent by the server to indicate acceptance
2732 of an incomplete client command and readiness for the remainder of
2733 the command.
2734
27357.1. Server Responses - Status Responses
2736
2737 Status responses are OK, NO, BAD, PREAUTH and BYE. OK, NO, and BAD
2738 may be tagged or untagged. PREAUTH and BYE are always untagged.
2739
2740 Status responses MAY include an OPTIONAL "response code". A response
2741 code consists of data inside square brackets in the form of an atom,
2742 possibly followed by a space and arguments. The response code
2743
2744
2745
2746Crispin Standards Track [Page 49]
2747
2748RFC 2060 IMAP4rev1 December 1996
2749
2750
2751 contains additional information or status codes for client software
2752 beyond the OK/NO/BAD condition, and are defined when there is a
2753 specific action that a client can take based upon the additional
2754 information.
2755
2756 The currently defined response codes are:
2757
2758 ALERT The human-readable text contains a special alert
2759 that MUST be presented to the user in a fashion
2760 that calls the user's attention to the message.
2761
2762 NEWNAME Followed by a mailbox name and a new mailbox name.
2763 A SELECT or EXAMINE is failing because the target
2764 mailbox name no longer exists because it was
2765 renamed to the new mailbox name. This is a hint to
2766 the client that the operation can succeed if the
2767 SELECT or EXAMINE is reissued with the new mailbox
2768 name.
2769
2770 PARSE The human-readable text represents an error in
2771 parsing the [RFC-822] header or [MIME-IMB] headers
2772 of a message in the mailbox.
2773
2774 PERMANENTFLAGS Followed by a parenthesized list of flags,
2775 indicates which of the known flags that the client
2776 can change permanently. Any flags that are in the
2777 FLAGS untagged response, but not the PERMANENTFLAGS
2778 list, can not be set permanently. If the client
2779 attempts to STORE a flag that is not in the
2780 PERMANENTFLAGS list, the server will either reject
2781 it with a NO reply or store the state for the
2782 remainder of the current session only. The
2783 PERMANENTFLAGS list can also include the special
2784 flag \*, which indicates that it is possible to
2785 create new keywords by attempting to store those
2786 flags in the mailbox.
2787
2788 READ-ONLY The mailbox is selected read-only, or its access
2789 while selected has changed from read-write to
2790 read-only.
2791
2792 READ-WRITE The mailbox is selected read-write, or its access
2793 while selected has changed from read-only to
2794 read-write.
2795
2796
2797
2798
2799
2800
2801
2802Crispin Standards Track [Page 50]
2803
2804RFC 2060 IMAP4rev1 December 1996
2805
2806
2807 TRYCREATE An APPEND or COPY attempt is failing because the
2808 target mailbox does not exist (as opposed to some
2809 other reason). This is a hint to the client that
2810 the operation can succeed if the mailbox is first
2811 created by the CREATE command.
2812
2813 UIDVALIDITY Followed by a decimal number, indicates the unique
2814 identifier validity value.
2815
2816 UNSEEN Followed by a decimal number, indicates the number
2817 of the first message without the \Seen flag set.
2818
2819 Additional response codes defined by particular client or server
2820 implementations SHOULD be prefixed with an "X" until they are
2821 added to a revision of this protocol. Client implementations
2822 SHOULD ignore response codes that they do not recognize.
2823
28247.1.1. OK Response
2825
2826 Contents: OPTIONAL response code
2827 human-readable text
2828
2829 The OK response indicates an information message from the server.
2830 When tagged, it indicates successful completion of the associated
2831 command. The human-readable text MAY be presented to the user as
2832 an information message. The untagged form indicates an
2833 information-only message; the nature of the information MAY be
2834 indicated by a response code.
2835
2836 The untagged form is also used as one of three possible greetings
2837 at connection startup. It indicates that the connection is not
2838 yet authenticated and that a LOGIN command is needed.
2839
2840 Example: S: * OK IMAP4rev1 server ready
2841 C: A001 LOGIN fred blurdybloop
2842 S: * OK [ALERT] System shutdown in 10 minutes
2843 S: A001 OK LOGIN Completed
2844
28457.1.2. NO Response
2846
2847 Contents: OPTIONAL response code
2848 human-readable text
2849
2850 The NO response indicates an operational error message from the
2851 server. When tagged, it indicates unsuccessful completion of the
2852 associated command. The untagged form indicates a warning; the
2853 command can still complete successfully. The human-readable text
2854 describes the condition.
2855
2856
2857
2858Crispin Standards Track [Page 51]
2859
2860RFC 2060 IMAP4rev1 December 1996
2861
2862
2863 Example: C: A222 COPY 1:2 owatagusiam
2864 S: * NO Disk is 98% full, please delete unnecessary data
2865 S: A222 OK COPY completed
2866 C: A223 COPY 3:200 blurdybloop
2867 S: * NO Disk is 98% full, please delete unnecessary data
2868 S: * NO Disk is 99% full, please delete unnecessary data
2869 S: A223 NO COPY failed: disk is full
2870
28717.1.3. BAD Response
2872
2873 Contents: OPTIONAL response code
2874 human-readable text
2875
2876 The BAD response indicates an error message from the server. When
2877 tagged, it reports a protocol-level error in the client's command;
2878 the tag indicates the command that caused the error. The untagged
2879 form indicates a protocol-level error for which the associated
2880 command can not be determined; it can also indicate an internal
2881 server failure. The human-readable text describes the condition.
2882
2883 Example: C: ...very long command line...
2884 S: * BAD Command line too long
2885 C: ...empty line...
2886 S: * BAD Empty command line
2887 C: A443 EXPUNGE
2888 S: * BAD Disk crash, attempting salvage to a new disk!
2889 S: * OK Salvage successful, no data lost
2890 S: A443 OK Expunge completed
2891
28927.1.4. PREAUTH Response
2893
2894 Contents: OPTIONAL response code
2895 human-readable text
2896
2897 The PREAUTH response is always untagged, and is one of three
2898 possible greetings at connection startup. It indicates that the
2899 connection has already been authenticated by external means and
2900 thus no LOGIN command is needed.
2901
2902 Example: S: * PREAUTH IMAP4rev1 server logged in as Smith
2903
29047.1.5. BYE Response
2905
2906 Contents: OPTIONAL response code
2907 human-readable text
2908
2909
2910
2911
2912
2913
2914Crispin Standards Track [Page 52]
2915
2916RFC 2060 IMAP4rev1 December 1996
2917
2918
2919 The BYE response is always untagged, and indicates that the server
2920 is about to close the connection. The human-readable text MAY be
2921 displayed to the user in a status report by the client. The BYE
2922 response is sent under one of four conditions:
2923
2924 1) as part of a normal logout sequence. The server will close
2925 the connection after sending the tagged OK response to the
2926 LOGOUT command.
2927
2928 2) as a panic shutdown announcement. The server closes the
2929 connection immediately.
2930
2931 3) as an announcement of an inactivity autologout. The server
2932 closes the connection immediately.
2933
2934 4) as one of three possible greetings at connection startup,
2935 indicating that the server is not willing to accept a
2936 connection from this client. The server closes the
2937 connection immediately.
2938
2939 The difference between a BYE that occurs as part of a normal
2940 LOGOUT sequence (the first case) and a BYE that occurs because of
2941 a failure (the other three cases) is that the connection closes
2942 immediately in the failure case.
2943
2944 Example: S: * BYE Autologout; idle for too long
2945
29467.2. Server Responses - Server and Mailbox Status
2947
2948 These responses are always untagged. This is how server and mailbox
2949 status data are transmitted from the server to the client. Many of
2950 these responses typically result from a command with the same name.
2951
29527.2.1. CAPABILITY Response
2953
2954 Contents: capability listing
2955
2956 The CAPABILITY response occurs as a result of a CAPABILITY
2957 command. The capability listing contains a space-separated
2958 listing of capability names that the server supports. The
2959 capability listing MUST include the atom "IMAP4rev1".
2960
2961 A capability name which begins with "AUTH=" indicates that the
2962 server supports that particular authentication mechanism.
2963
2964
2965
2966
2967
2968
2969
2970Crispin Standards Track [Page 53]
2971
2972RFC 2060 IMAP4rev1 December 1996
2973
2974
2975 Other capability names indicate that the server supports an
2976 extension, revision, or amendment to the IMAP4rev1 protocol.
2977 Server responses MUST conform to this document until the client
2978 issues a command that uses the associated capability.
2979
2980 Capability names MUST either begin with "X" or be standard or
2981 standards-track IMAP4rev1 extensions, revisions, or amendments
2982 registered with IANA. A server MUST NOT offer unregistered or
2983 non-standard capability names, unless such names are prefixed with
2984 an "X".
2985
2986 Client implementations SHOULD NOT require any capability name
2987 other than "IMAP4rev1", and MUST ignore any unknown capability
2988 names.
2989
2990 Example: S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4 XPIG-LATIN
2991
29927.2.2. LIST Response
2993
2994 Contents: name attributes
2995 hierarchy delimiter
2996 name
2997
2998 The LIST response occurs as a result of a LIST command. It
2999 returns a single name that matches the LIST specification. There
3000 can be multiple LIST responses for a single LIST command.
3001
3002 Four name attributes are defined:
3003
3004 \Noinferiors It is not possible for any child levels of
3005 hierarchy to exist under this name; no child levels
3006 exist now and none can be created in the future.
3007
3008 \Noselect It is not possible to use this name as a selectable
3009 mailbox.
3010
3011 \Marked The mailbox has been marked "interesting" by the
3012 server; the mailbox probably contains messages that
3013 have been added since the last time the mailbox was
3014 selected.
3015
3016 \Unmarked The mailbox does not contain any additional
3017 messages since the last time the mailbox was
3018 selected.
3019
3020 If it is not feasible for the server to determine whether the
3021 mailbox is "interesting" or not, or if the name is a \Noselect
3022 name, the server SHOULD NOT send either \Marked or \Unmarked.
3023
3024
3025
3026Crispin Standards Track [Page 54]
3027
3028RFC 2060 IMAP4rev1 December 1996
3029
3030
3031 The hierarchy delimiter is a character used to delimit levels of
3032 hierarchy in a mailbox name. A client can use it to create child
3033 mailboxes, and to search higher or lower levels of naming
3034 hierarchy. All children of a top-level hierarchy node MUST use
3035 the same separator character. A NIL hierarchy delimiter means
3036 that no hierarchy exists; the name is a "flat" name.
3037
3038 The name represents an unambiguous left-to-right hierarchy, and
3039 MUST be valid for use as a reference in LIST and LSUB commands.
3040 Unless \Noselect is indicated, the name MUST also be valid as an
3041 argument for commands, such as SELECT, that accept mailbox
3042 names.
3043
3044 Example: S: * LIST (\Noselect) "/" ~/Mail/foo
3045
30467.2.3. LSUB Response
3047
3048 Contents: name attributes
3049 hierarchy delimiter
3050 name
3051
3052 The LSUB response occurs as a result of an LSUB command. It
3053 returns a single name that matches the LSUB specification. There
3054 can be multiple LSUB responses for a single LSUB command. The
3055 data is identical in format to the LIST response.
3056
3057 Example: S: * LSUB () "." #news.comp.mail.misc
3058
30597.2.4 STATUS Response
3060
3061 Contents: name
3062 status parenthesized list
3063
3064 The STATUS response occurs as a result of an STATUS command. It
3065 returns the mailbox name that matches the STATUS specification and
3066 the requested mailbox status information.
3067
3068 Example: S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
3069
30707.2.5. SEARCH Response
3071
3072 Contents: zero or more numbers
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082Crispin Standards Track [Page 55]
3083
3084RFC 2060 IMAP4rev1 December 1996
3085
3086
3087 The SEARCH response occurs as a result of a SEARCH or UID SEARCH
3088 command. The number(s) refer to those messages that match the
3089 search criteria. For SEARCH, these are message sequence numbers;
3090 for UID SEARCH, these are unique identifiers. Each number is
3091 delimited by a space.
3092
3093 Example: S: * SEARCH 2 3 6
3094
30957.2.6. FLAGS Response
3096
3097 Contents: flag parenthesized list
3098
3099 The FLAGS response occurs as a result of a SELECT or EXAMINE
3100 command. The flag parenthesized list identifies the flags (at a
3101 minimum, the system-defined flags) that are applicable for this
3102 mailbox. Flags other than the system flags can also exist,
3103 depending on server implementation.
3104
3105 The update from the FLAGS response MUST be recorded by the client.
3106
3107 Example: S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
3108
31097.3. Server Responses - Mailbox Size
3110
3111 These responses are always untagged. This is how changes in the size
3112 of the mailbox are trasnmitted from the server to the client.
3113 Immediately following the "*" token is a number that represents a
3114 message count.
3115
31167.3.1. EXISTS Response
3117
3118 Contents: none
3119
3120 The EXISTS response reports the number of messages in the mailbox.
3121 This response occurs as a result of a SELECT or EXAMINE command,
3122 and if the size of the mailbox changes (e.g. new mail).
3123
3124 The update from the EXISTS response MUST be recorded by the
3125 client.
3126
3127 Example: S: * 23 EXISTS
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138Crispin Standards Track [Page 56]
3139
3140RFC 2060 IMAP4rev1 December 1996
3141
3142
31437.3.2. RECENT Response
3144
3145 Contents: none
3146
3147 The RECENT response reports the number of messages with the
3148 \Recent flag set. This response occurs as a result of a SELECT or
3149 EXAMINE command, and if the size of the mailbox changes (e.g. new
3150 mail).
3151
3152 Note: It is not guaranteed that the message sequence numbers of
3153 recent messages will be a contiguous range of the highest n
3154 messages in the mailbox (where n is the value reported by the
3155 RECENT response). Examples of situations in which this is not
3156 the case are: multiple clients having the same mailbox open
3157 (the first session to be notified will see it as recent, others
3158 will probably see it as non-recent), and when the mailbox is
3159 re-ordered by a non-IMAP agent.
3160
3161 The only reliable way to identify recent messages is to look at
3162 message flags to see which have the \Recent flag set, or to do
3163 a SEARCH RECENT.
3164
3165 The update from the RECENT response MUST be recorded by the
3166 client.
3167
3168 Example: S: * 5 RECENT
3169
31707.4. Server Responses - Message Status
3171
3172 These responses are always untagged. This is how message data are
3173 transmitted from the server to the client, often as a result of a
3174 command with the same name. Immediately following the "*" token is a
3175 number that represents a message sequence number.
3176
31777.4.1. EXPUNGE Response
3178
3179 Contents: none
3180
3181 The EXPUNGE response reports that the specified message sequence
3182 number has been permanently removed from the mailbox. The message
3183 sequence number for each successive message in the mailbox is
3184 immediately decremented by 1, and this decrement is reflected in
3185 message sequence numbers in subsequent responses (including other
3186 untagged EXPUNGE responses).
3187
3188 As a result of the immediate decrement rule, message sequence
3189 numbers that appear in a set of successive EXPUNGE responses
3190 depend upon whether the messages are removed starting from lower
3191
3192
3193
3194Crispin Standards Track [Page 57]
3195
3196RFC 2060 IMAP4rev1 December 1996
3197
3198
3199 numbers to higher numbers, or from higher numbers to lower
3200 numbers. For example, if the last 5 messages in a 9-message
3201 mailbox are expunged; a "lower to higher" server will send five
3202 untagged EXPUNGE responses for message sequence number 5, whereas
3203 a "higher to lower server" will send successive untagged EXPUNGE
3204 responses for message sequence numbers 9, 8, 7, 6, and 5.
3205
3206 An EXPUNGE response MUST NOT be sent when no command is in
3207 progress; nor while responding to a FETCH, STORE, or SEARCH
3208 command. This rule is necessary to prevent a loss of
3209 synchronization of message sequence numbers between client and
3210 server.
3211
3212 The update from the EXPUNGE response MUST be recorded by the
3213 client.
3214
3215 Example: S: * 44 EXPUNGE
3216
32177.4.2. FETCH Response
3218
3219 Contents: message data
3220
3221 The FETCH response returns data about a message to the client.
3222 The data are pairs of data item names and their values in
3223 parentheses. This response occurs as the result of a FETCH or
3224 STORE command, as well as by unilateral server decision (e.g. flag
3225 updates).
3226
3227 The current data items are:
3228
3229 BODY A form of BODYSTRUCTURE without extension data.
3230
3231 BODY[<section>]<<origin_octet>>
3232 A string expressing the body contents of the
3233 specified section. The string SHOULD be
3234 interpreted by the client according to the content
3235 transfer encoding, body type, and subtype.
3236
3237 If the origin octet is specified, this string is a
3238 substring of the entire body contents, starting at
3239 that origin octet. This means that BODY[]<0> MAY
3240 be truncated, but BODY[] is NEVER truncated.
3241
3242 8-bit textual data is permitted if a [CHARSET]
3243 identifier is part of the body parameter
3244 parenthesized list for this section. Note that
3245 headers (part specifiers HEADER or MIME, or the
3246 header portion of a MESSAGE/RFC822 part), MUST be
3247
3248
3249
3250Crispin Standards Track [Page 58]
3251
3252RFC 2060 IMAP4rev1 December 1996
3253
3254
3255 7-bit; 8-bit characters are not permitted in
3256 headers. Note also that the blank line at the end
3257 of the header is always included in header data.
3258
3259 Non-textual data such as binary data MUST be
3260 transfer encoded into a textual form such as BASE64
3261 prior to being sent to the client. To derive the
3262 original binary data, the client MUST decode the
3263 transfer encoded string.
3264
3265 BODYSTRUCTURE A parenthesized list that describes the [MIME-IMB]
3266 body structure of a message. This is computed by
3267 the server by parsing the [MIME-IMB] header fields,
3268 defaulting various fields as necessary.
3269
3270 For example, a simple text message of 48 lines and
3271 2279 octets can have a body structure of: ("TEXT"
3272 "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 2279
3273 48)
3274
3275 Multiple parts are indicated by parenthesis
3276 nesting. Instead of a body type as the first
3277 element of the parenthesized list there is a nested
3278 body. The second element of the parenthesized list
3279 is the multipart subtype (mixed, digest, parallel,
3280 alternative, etc.).
3281
3282 For example, a two part message consisting of a
3283 text and a BASE645-encoded text attachment can have
3284 a body structure of: (("TEXT" "PLAIN" ("CHARSET"
3285 "US-ASCII") NIL NIL "7BIT" 1152 23)("TEXT" "PLAIN"
3286 ("CHARSET" "US-ASCII" "NAME" "cc.diff")
3287 "<960723163407.20117h@cac.washington.edu>"
3288 "Compiler diff" "BASE64" 4554 73) "MIXED"))
3289
3290 Extension data follows the multipart subtype.
3291 Extension data is never returned with the BODY
3292 fetch, but can be returned with a BODYSTRUCTURE
3293 fetch. Extension data, if present, MUST be in the
3294 defined order.
3295
3296 The extension data of a multipart body part are in
3297 the following order:
3298
3299 body parameter parenthesized list
3300 A parenthesized list of attribute/value pairs
3301 [e.g. ("foo" "bar" "baz" "rag") where "bar" is
3302 the value of "foo" and "rag" is the value of
3303
3304
3305
3306Crispin Standards Track [Page 59]
3307
3308RFC 2060 IMAP4rev1 December 1996
3309
3310
3311 "baz"] as defined in [MIME-IMB].
3312
3313 body disposition
3314 A parenthesized list, consisting of a
3315 disposition type string followed by a
3316 parenthesized list of disposition
3317 attribute/value pairs. The disposition type and
3318 attribute names will be defined in a future
3319 standards-track revision to [DISPOSITION].
3320
3321 body language
3322 A string or parenthesized list giving the body
3323 language value as defined in [LANGUAGE-TAGS].
3324
3325 Any following extension data are not yet defined in
3326 this version of the protocol. Such extension data
3327 can consist of zero or more NILs, strings, numbers,
3328 or potentially nested parenthesized lists of such
3329 data. Client implementations that do a
3330 BODYSTRUCTURE fetch MUST be prepared to accept such
3331 extension data. Server implementations MUST NOT
3332 send such extension data until it has been defined
3333 by a revision of this protocol.
3334
3335 The basic fields of a non-multipart body part are
3336 in the following order:
3337
3338 body type
3339 A string giving the content media type name as
3340 defined in [MIME-IMB].
3341
3342 body subtype
3343 A string giving the content subtype name as
3344 defined in [MIME-IMB].
3345
3346 body parameter parenthesized list
3347 A parenthesized list of attribute/value pairs
3348 [e.g. ("foo" "bar" "baz" "rag") where "bar" is
3349 the value of "foo" and "rag" is the value of
3350 "baz"] as defined in [MIME-IMB].
3351
3352 body id
3353 A string giving the content id as defined in
3354 [MIME-IMB].
3355
3356 body description
3357 A string giving the content description as
3358 defined in [MIME-IMB].
3359
3360
3361
3362Crispin Standards Track [Page 60]
3363
3364RFC 2060 IMAP4rev1 December 1996
3365
3366
3367 body encoding
3368 A string giving the content transfer encoding as
3369 defined in [MIME-IMB].
3370
3371 body size
3372 A number giving the size of the body in octets.
3373 Note that this size is the size in its transfer
3374 encoding and not the resulting size after any
3375 decoding.
3376
3377 A body type of type MESSAGE and subtype RFC822
3378 contains, immediately after the basic fields, the
3379 envelope structure, body structure, and size in
3380 text lines of the encapsulated message.
3381
3382 A body type of type TEXT contains, immediately
3383 after the basic fields, the size of the body in
3384 text lines. Note that this size is the size in its
3385 content transfer encoding and not the resulting
3386 size after any decoding.
3387
3388 Extension data follows the basic fields and the
3389 type-specific fields listed above. Extension data
3390 is never returned with the BODY fetch, but can be
3391 returned with a BODYSTRUCTURE fetch. Extension
3392 data, if present, MUST be in the defined order.
3393
3394 The extension data of a non-multipart body part are
3395 in the following order:
3396
3397 body MD5
3398 A string giving the body MD5 value as defined in
3399 [MD5].
3400
3401 body disposition
3402 A parenthesized list with the same content and
3403 function as the body disposition for a multipart
3404 body part.
3405
3406 body language
3407 A string or parenthesized list giving the body
3408 language value as defined in [LANGUAGE-TAGS].
3409
3410 Any following extension data are not yet defined in
3411 this version of the protocol, and would be as
3412 described above under multipart extension data.
3413
3414
3415
3416
3417
3418Crispin Standards Track [Page 61]
3419
3420RFC 2060 IMAP4rev1 December 1996
3421
3422
3423 ENVELOPE A parenthesized list that describes the envelope
3424 structure of a message. This is computed by the
3425 server by parsing the [RFC-822] header into the
3426 component parts, defaulting various fields as
3427 necessary.
3428
3429 The fields of the envelope structure are in the
3430 following order: date, subject, from, sender,
3431 reply-to, to, cc, bcc, in-reply-to, and message-id.
3432 The date, subject, in-reply-to, and message-id
3433 fields are strings. The from, sender, reply-to,
3434 to, cc, and bcc fields are parenthesized lists of
3435 address structures.
3436
3437 An address structure is a parenthesized list that
3438 describes an electronic mail address. The fields
3439 of an address structure are in the following order:
3440 personal name, [SMTP] at-domain-list (source
3441 route), mailbox name, and host name.
3442
3443 [RFC-822] group syntax is indicated by a special
3444 form of address structure in which the host name
3445 field is NIL. If the mailbox name field is also
3446 NIL, this is an end of group marker (semi-colon in
3447 RFC 822 syntax). If the mailbox name field is
3448 non-NIL, this is a start of group marker, and the
3449 mailbox name field holds the group name phrase.
3450
3451 Any field of an envelope or address structure that
3452 is not applicable is presented as NIL. Note that
3453 the server MUST default the reply-to and sender
3454 fields from the from field; a client is not
3455 expected to know to do this.
3456
3457 FLAGS A parenthesized list of flags that are set for this
3458 message.
3459
3460 INTERNALDATE A string representing the internal date of the
3461 message.
3462
3463 RFC822 Equivalent to BODY[].
3464
3465 RFC822.HEADER Equivalent to BODY.PEEK[HEADER].
3466
3467 RFC822.SIZE A number expressing the [RFC-822] size of the
3468 message.
3469
3470 RFC822.TEXT Equivalent to BODY[TEXT].
3471
3472
3473
3474Crispin Standards Track [Page 62]
3475
3476RFC 2060 IMAP4rev1 December 1996
3477
3478
3479 UID A number expressing the unique identifier of the
3480 message.
3481
3482
3483 Example: S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827)
3484
34857.5. Server Responses - Command Continuation Request
3486
3487 The command continuation request response is indicated by a "+" token
3488 instead of a tag. This form of response indicates that the server is
3489 ready to accept the continuation of a command from the client. The
3490 remainder of this response is a line of text.
3491
3492 This response is used in the AUTHORIZATION command to transmit server
3493 data to the client, and request additional client data. This
3494 response is also used if an argument to any command is a literal.
3495
3496 The client is not permitted to send the octets of the literal unless
3497 the server indicates that it expects it. This permits the server to
3498 process commands and reject errors on a line-by-line basis. The
3499 remainder of the command, including the CRLF that terminates a
3500 command, follows the octets of the literal. If there are any
3501 additional command arguments the literal octets are followed by a
3502 space and those arguments.
3503
3504 Example: C: A001 LOGIN {11}
3505 S: + Ready for additional command text
3506 C: FRED FOOBAR {7}
3507 S: + Ready for additional command text
3508 C: fat man
3509 S: A001 OK LOGIN completed
3510 C: A044 BLURDYBLOOP {102856}
3511 S: A044 BAD No such command as "BLURDYBLOOP"
3512
35138. Sample IMAP4rev1 connection
3514
3515 The following is a transcript of an IMAP4rev1 connection. A long
3516 line in this sample is broken for editorial clarity.
3517
3518S: * OK IMAP4rev1 Service Ready
3519C: a001 login mrc secret
3520S: a001 OK LOGIN completed
3521C: a002 select inbox
3522S: * 18 EXISTS
3523S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
3524S: * 2 RECENT
3525S: * OK [UNSEEN 17] Message 17 is the first unseen message
3526S: * OK [UIDVALIDITY 3857529045] UIDs valid
3527
3528
3529
3530Crispin Standards Track [Page 63]
3531
3532RFC 2060 IMAP4rev1 December 1996
3533
3534
3535S: a002 OK [READ-WRITE] SELECT completed
3536C: a003 fetch 12 full
3537S: * 12 FETCH (FLAGS (\Seen) INTERNALDATE "17-Jul-1996 02:44:25 -0700"
3538 RFC822.SIZE 4286 ENVELOPE ("Wed, 17 Jul 1996 02:23:25 -0700 (PDT)"
3539 "IMAP4rev1 WG mtg summary and minutes"
3540 (("Terry Gray" NIL "gray" "cac.washington.edu"))
3541 (("Terry Gray" NIL "gray" "cac.washington.edu"))
3542 (("Terry Gray" NIL "gray" "cac.washington.edu"))
3543 ((NIL NIL "imap" "cac.washington.edu"))
3544 ((NIL NIL "minutes" "CNRI.Reston.VA.US")
3545 ("John Klensin" NIL "KLENSIN" "INFOODS.MIT.EDU")) NIL NIL
3546 "<B27397-0100000@cac.washington.edu>")
3547 BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 3028 92))
3548S: a003 OK FETCH completed
3549C: a004 fetch 12 body[header]
3550S: * 12 FETCH (BODY[HEADER] {350}
3551S: Date: Wed, 17 Jul 1996 02:23:25 -0700 (PDT)
3552S: From: Terry Gray <gray@cac.washington.edu>
3553S: Subject: IMAP4rev1 WG mtg summary and minutes
3554S: To: imap@cac.washington.edu
3555S: cc: minutes@CNRI.Reston.VA.US, John Klensin <KLENSIN@INFOODS.MIT.EDU>
3556S: Message-Id: <B27397-0100000@cac.washington.edu>
3557S: MIME-Version: 1.0
3558S: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
3559S:
3560S: )
3561S: a004 OK FETCH completed
3562C: a005 store 12 +flags \deleted
3563S: * 12 FETCH (FLAGS (\Seen \Deleted))
3564S: a005 OK +FLAGS completed
3565C: a006 logout
3566S: * BYE IMAP4rev1 server terminating connection
3567S: a006 OK LOGOUT completed
3568
35699. Formal Syntax
3570
3571 The following syntax specification uses the augmented Backus-Naur
3572 Form (BNF) notation as specified in [RFC-822] with one exception; the
3573 delimiter used with the "#" construct is a single space (SPACE) and
3574 not one or more commas.
3575
3576 In the case of alternative or optional rules in which a later rule
3577 overlaps an earlier rule, the rule which is listed earlier MUST take
3578 priority. For example, "\Seen" when parsed as a flag is the \Seen
3579 flag name and not a flag_extension, even though "\Seen" could be
3580 parsed as a flag_extension. Some, but not all, instances of this
3581 rule are noted below.
3582
3583
3584
3585
3586Crispin Standards Track [Page 64]
3587
3588RFC 2060 IMAP4rev1 December 1996
3589
3590
3591 Except as noted otherwise, all alphabetic characters are case-
3592 insensitive. The use of upper or lower case characters to define
3593 token strings is for editorial clarity only. Implementations MUST
3594 accept these strings in a case-insensitive fashion.
3595
3596address ::= "(" addr_name SPACE addr_adl SPACE addr_mailbox
3597 SPACE addr_host ")"
3598
3599addr_adl ::= nstring
3600 ;; Holds route from [RFC-822] route-addr if
3601 ;; non-NIL
3602
3603addr_host ::= nstring
3604 ;; NIL indicates [RFC-822] group syntax.
3605 ;; Otherwise, holds [RFC-822] domain name
3606
3607addr_mailbox ::= nstring
3608 ;; NIL indicates end of [RFC-822] group; if
3609 ;; non-NIL and addr_host is NIL, holds
3610 ;; [RFC-822] group name.
3611 ;; Otherwise, holds [RFC-822] local-part
3612
3613addr_name ::= nstring
3614 ;; Holds phrase from [RFC-822] mailbox if
3615 ;; non-NIL
3616
3617alpha ::= "A" / "B" / "C" / "D" / "E" / "F" / "G" / "H" /
3618 "I" / "J" / "K" / "L" / "M" / "N" / "O" / "P" /
3619 "Q" / "R" / "S" / "T" / "U" / "V" / "W" / "X" /
3620 "Y" / "Z" /
3621 "a" / "b" / "c" / "d" / "e" / "f" / "g" / "h" /
3622 "i" / "j" / "k" / "l" / "m" / "n" / "o" / "p" /
3623 "q" / "r" / "s" / "t" / "u" / "v" / "w" / "x" /
3624 "y" / "z"
3625 ;; Case-sensitive
3626
3627append ::= "APPEND" SPACE mailbox [SPACE flag_list]
3628 [SPACE date_time] SPACE literal
3629
3630astring ::= atom / string
3631
3632atom ::= 1*ATOM_CHAR
3633
3634ATOM_CHAR ::= <any CHAR except atom_specials>
3635
3636atom_specials ::= "(" / ")" / "{" / SPACE / CTL / list_wildcards /
3637 quoted_specials
3638
3639
3640
3641
3642Crispin Standards Track [Page 65]
3643
3644RFC 2060 IMAP4rev1 December 1996
3645
3646
3647authenticate ::= "AUTHENTICATE" SPACE auth_type *(CRLF base64)
3648
3649auth_type ::= atom
3650 ;; Defined by [IMAP-AUTH]
3651
3652base64 ::= *(4base64_char) [base64_terminal]
3653
3654base64_char ::= alpha / digit / "+" / "/"
3655
3656base64_terminal ::= (2base64_char "==") / (3base64_char "=")
3657
3658body ::= "(" body_type_1part / body_type_mpart ")"
3659
3660body_extension ::= nstring / number / "(" 1#body_extension ")"
3661 ;; Future expansion. Client implementations
3662 ;; MUST accept body_extension fields. Server
3663 ;; implementations MUST NOT generate
3664 ;; body_extension fields except as defined by
3665 ;; future standard or standards-track
3666 ;; revisions of this specification.
3667
3668body_ext_1part ::= body_fld_md5 [SPACE body_fld_dsp
3669 [SPACE body_fld_lang
3670 [SPACE 1#body_extension]]]
3671 ;; MUST NOT be returned on non-extensible
3672 ;; "BODY" fetch
3673
3674body_ext_mpart ::= body_fld_param
3675 [SPACE body_fld_dsp SPACE body_fld_lang
3676 [SPACE 1#body_extension]]
3677 ;; MUST NOT be returned on non-extensible
3678 ;; "BODY" fetch
3679
3680body_fields ::= body_fld_param SPACE body_fld_id SPACE
3681 body_fld_desc SPACE body_fld_enc SPACE
3682 body_fld_octets
3683
3684body_fld_desc ::= nstring
3685
3686body_fld_dsp ::= "(" string SPACE body_fld_param ")" / nil
3687
3688body_fld_enc ::= (<"> ("7BIT" / "8BIT" / "BINARY" / "BASE64"/
3689 "QUOTED-PRINTABLE") <">) / string
3690
3691body_fld_id ::= nstring
3692
3693body_fld_lang ::= nstring / "(" 1#string ")"
3694
3695
3696
3697
3698Crispin Standards Track [Page 66]
3699
3700RFC 2060 IMAP4rev1 December 1996
3701
3702
3703body_fld_lines ::= number
3704
3705body_fld_md5 ::= nstring
3706
3707body_fld_octets ::= number
3708
3709body_fld_param ::= "(" 1#(string SPACE string) ")" / nil
3710
3711body_type_1part ::= (body_type_basic / body_type_msg / body_type_text)
3712 [SPACE body_ext_1part]
3713
3714body_type_basic ::= media_basic SPACE body_fields
3715 ;; MESSAGE subtype MUST NOT be "RFC822"
3716
3717body_type_mpart ::= 1*body SPACE media_subtype
3718 [SPACE body_ext_mpart]
3719
3720body_type_msg ::= media_message SPACE body_fields SPACE envelope
3721 SPACE body SPACE body_fld_lines
3722
3723body_type_text ::= media_text SPACE body_fields SPACE body_fld_lines
3724
3725capability ::= "AUTH=" auth_type / atom
3726 ;; New capabilities MUST begin with "X" or be
3727 ;; registered with IANA as standard or
3728 ;; standards-track
3729
3730capability_data ::= "CAPABILITY" SPACE [1#capability SPACE] "IMAP4rev1"
3731 [SPACE 1#capability]
3732 ;; IMAP4rev1 servers which offer RFC 1730
3733 ;; compatibility MUST list "IMAP4" as the first
3734 ;; capability.
3735
3736CHAR ::= <any 7-bit US-ASCII character except NUL,
3737 0x01 - 0x7f>
3738
3739CHAR8 ::= <any 8-bit octet except NUL, 0x01 - 0xff>
3740
3741command ::= tag SPACE (command_any / command_auth /
3742 command_nonauth / command_select) CRLF
3743 ;; Modal based on state
3744
3745command_any ::= "CAPABILITY" / "LOGOUT" / "NOOP" / x_command
3746 ;; Valid in all states
3747
3748command_auth ::= append / create / delete / examine / list / lsub /
3749 rename / select / status / subscribe / unsubscribe
3750 ;; Valid only in Authenticated or Selected state
3751
3752
3753
3754Crispin Standards Track [Page 67]
3755
3756RFC 2060 IMAP4rev1 December 1996
3757
3758
3759command_nonauth ::= login / authenticate
3760 ;; Valid only when in Non-Authenticated state
3761
3762command_select ::= "CHECK" / "CLOSE" / "EXPUNGE" /
3763 copy / fetch / store / uid / search
3764 ;; Valid only when in Selected state
3765
3766continue_req ::= "+" SPACE (resp_text / base64)
3767
3768copy ::= "COPY" SPACE set SPACE mailbox
3769
3770CR ::= <ASCII CR, carriage return, 0x0D>
3771
3772create ::= "CREATE" SPACE mailbox
3773 ;; Use of INBOX gives a NO error
3774
3775CRLF ::= CR LF
3776
3777CTL ::= <any ASCII control character and DEL,
3778 0x00 - 0x1f, 0x7f>
3779
3780date ::= date_text / <"> date_text <">
3781
3782date_day ::= 1*2digit
3783 ;; Day of month
3784
3785date_day_fixed ::= (SPACE digit) / 2digit
3786 ;; Fixed-format version of date_day
3787
3788date_month ::= "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" /
3789 "Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec"
3790
3791date_text ::= date_day "-" date_month "-" date_year
3792
3793date_year ::= 4digit
3794
3795date_time ::= <"> date_day_fixed "-" date_month "-" date_year
3796 SPACE time SPACE zone <">
3797
3798delete ::= "DELETE" SPACE mailbox
3799 ;; Use of INBOX gives a NO error
3800
3801digit ::= "0" / digit_nz
3802
3803digit_nz ::= "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" /
3804 "9"
3805
3806
3807
3808
3809
3810Crispin Standards Track [Page 68]
3811
3812RFC 2060 IMAP4rev1 December 1996
3813
3814
3815envelope ::= "(" env_date SPACE env_subject SPACE env_from
3816 SPACE env_sender SPACE env_reply_to SPACE env_to
3817 SPACE env_cc SPACE env_bcc SPACE env_in_reply_to
3818 SPACE env_message_id ")"
3819
3820env_bcc ::= "(" 1*address ")" / nil
3821
3822env_cc ::= "(" 1*address ")" / nil
3823
3824env_date ::= nstring
3825
3826env_from ::= "(" 1*address ")" / nil
3827
3828env_in_reply_to ::= nstring
3829
3830env_message_id ::= nstring
3831
3832env_reply_to ::= "(" 1*address ")" / nil
3833
3834env_sender ::= "(" 1*address ")" / nil
3835
3836env_subject ::= nstring
3837
3838env_to ::= "(" 1*address ")" / nil
3839
3840examine ::= "EXAMINE" SPACE mailbox
3841
3842fetch ::= "FETCH" SPACE set SPACE ("ALL" / "FULL" /
3843 "FAST" / fetch_att / "(" 1#fetch_att ")")
3844
3845fetch_att ::= "ENVELOPE" / "FLAGS" / "INTERNALDATE" /
3846 "RFC822" [".HEADER" / ".SIZE" / ".TEXT"] /
3847 "BODY" ["STRUCTURE"] / "UID" /
3848 "BODY" [".PEEK"] section
3849 ["<" number "." nz_number ">"]
3850
3851flag ::= "\Answered" / "\Flagged" / "\Deleted" /
3852 "\Seen" / "\Draft" / flag_keyword / flag_extension
3853
3854flag_extension ::= "\" atom
3855 ;; Future expansion. Client implementations
3856 ;; MUST accept flag_extension flags. Server
3857 ;; implementations MUST NOT generate
3858 ;; flag_extension flags except as defined by
3859 ;; future standard or standards-track
3860 ;; revisions of this specification.
3861
3862flag_keyword ::= atom
3863
3864
3865
3866Crispin Standards Track [Page 69]
3867
3868RFC 2060 IMAP4rev1 December 1996
3869
3870
3871flag_list ::= "(" #flag ")"
3872
3873greeting ::= "*" SPACE (resp_cond_auth / resp_cond_bye) CRLF
3874
3875header_fld_name ::= astring
3876
3877header_list ::= "(" 1#header_fld_name ")"
3878
3879LF ::= <ASCII LF, line feed, 0x0A>
3880
3881list ::= "LIST" SPACE mailbox SPACE list_mailbox
3882
3883list_mailbox ::= 1*(ATOM_CHAR / list_wildcards) / string
3884
3885list_wildcards ::= "%" / "*"
3886
3887literal ::= "{" number "}" CRLF *CHAR8
3888 ;; Number represents the number of CHAR8 octets
3889
3890login ::= "LOGIN" SPACE userid SPACE password
3891
3892lsub ::= "LSUB" SPACE mailbox SPACE list_mailbox
3893
3894mailbox ::= "INBOX" / astring
3895 ;; INBOX is case-insensitive. All case variants of
3896 ;; INBOX (e.g. "iNbOx") MUST be interpreted as INBOX
3897 ;; not as an astring. Refer to section 5.1 for
3898 ;; further semantic details of mailbox names.
3899
3900mailbox_data ::= "FLAGS" SPACE flag_list /
3901 "LIST" SPACE mailbox_list /
3902 "LSUB" SPACE mailbox_list /
3903 "MAILBOX" SPACE text /
3904 "SEARCH" [SPACE 1#nz_number] /
3905 "STATUS" SPACE mailbox SPACE
3906 "(" #<status_att number ")" /
3907 number SPACE "EXISTS" / number SPACE "RECENT"
3908
3909mailbox_list ::= "(" #("\Marked" / "\Noinferiors" /
3910 "\Noselect" / "\Unmarked" / flag_extension) ")"
3911 SPACE (<"> QUOTED_CHAR <"> / nil) SPACE mailbox
3912
3913media_basic ::= (<"> ("APPLICATION" / "AUDIO" / "IMAGE" /
3914 "MESSAGE" / "VIDEO") <">) / string)
3915 SPACE media_subtype
3916 ;; Defined in [MIME-IMT]
3917
3918media_message ::= <"> "MESSAGE" <"> SPACE <"> "RFC822" <">
3919
3920
3921
3922Crispin Standards Track [Page 70]
3923
3924RFC 2060 IMAP4rev1 December 1996
3925
3926
3927 ;; Defined in [MIME-IMT]
3928
3929media_subtype ::= string
3930 ;; Defined in [MIME-IMT]
3931
3932media_text ::= <"> "TEXT" <"> SPACE media_subtype
3933 ;; Defined in [MIME-IMT]
3934
3935message_data ::= nz_number SPACE ("EXPUNGE" /
3936 ("FETCH" SPACE msg_att))
3937
3938msg_att ::= "(" 1#("ENVELOPE" SPACE envelope /
3939 "FLAGS" SPACE "(" #(flag / "\Recent") ")" /
3940 "INTERNALDATE" SPACE date_time /
3941 "RFC822" [".HEADER" / ".TEXT"] SPACE nstring /
3942 "RFC822.SIZE" SPACE number /
3943 "BODY" ["STRUCTURE"] SPACE body /
3944 "BODY" section ["<" number ">"] SPACE nstring /
3945 "UID" SPACE uniqueid) ")"
3946
3947nil ::= "NIL"
3948
3949nstring ::= string / nil
3950
3951number ::= 1*digit
3952 ;; Unsigned 32-bit integer
3953 ;; (0 <= n < 4,294,967,296)
3954
3955nz_number ::= digit_nz *digit
3956 ;; Non-zero unsigned 32-bit integer
3957 ;; (0 < n < 4,294,967,296)
3958
3959password ::= astring
3960
3961quoted ::= <"> *QUOTED_CHAR <">
3962
3963QUOTED_CHAR ::= <any TEXT_CHAR except quoted_specials> /
3964 "\" quoted_specials
3965
3966quoted_specials ::= <"> / "\"
3967
3968rename ::= "RENAME" SPACE mailbox SPACE mailbox
3969 ;; Use of INBOX as a destination gives a NO error
3970
3971response ::= *(continue_req / response_data) response_done
3972
3973response_data ::= "*" SPACE (resp_cond_state / resp_cond_bye /
3974 mailbox_data / message_data / capability_data)
3975
3976
3977
3978Crispin Standards Track [Page 71]
3979
3980RFC 2060 IMAP4rev1 December 1996
3981
3982
3983 CRLF
3984
3985response_done ::= response_tagged / response_fatal
3986
3987response_fatal ::= "*" SPACE resp_cond_bye CRLF
3988 ;; Server closes connection immediately
3989
3990response_tagged ::= tag SPACE resp_cond_state CRLF
3991
3992resp_cond_auth ::= ("OK" / "PREAUTH") SPACE resp_text
3993 ;; Authentication condition
3994
3995resp_cond_bye ::= "BYE" SPACE resp_text
3996
3997resp_cond_state ::= ("OK" / "NO" / "BAD") SPACE resp_text
3998 ;; Status condition
3999
4000resp_text ::= ["[" resp_text_code "]" SPACE] (text_mime2 / text)
4001 ;; text SHOULD NOT begin with "[" or "="
4002
4003resp_text_code ::= "ALERT" / "PARSE" /
4004 "PERMANENTFLAGS" SPACE "(" #(flag / "\*") ")" /
4005 "READ-ONLY" / "READ-WRITE" / "TRYCREATE" /
4006 "UIDVALIDITY" SPACE nz_number /
4007 "UNSEEN" SPACE nz_number /
4008 atom [SPACE 1*<any TEXT_CHAR except "]">]
4009
4010search ::= "SEARCH" SPACE ["CHARSET" SPACE astring SPACE]
4011 1#search_key
4012 ;; [CHARSET] MUST be registered with IANA
4013
4014search_key ::= "ALL" / "ANSWERED" / "BCC" SPACE astring /
4015 "BEFORE" SPACE date / "BODY" SPACE astring /
4016 "CC" SPACE astring / "DELETED" / "FLAGGED" /
4017 "FROM" SPACE astring /
4018 "KEYWORD" SPACE flag_keyword / "NEW" / "OLD" /
4019 "ON" SPACE date / "RECENT" / "SEEN" /
4020 "SINCE" SPACE date / "SUBJECT" SPACE astring /
4021 "TEXT" SPACE astring / "TO" SPACE astring /
4022 "UNANSWERED" / "UNDELETED" / "UNFLAGGED" /
4023 "UNKEYWORD" SPACE flag_keyword / "UNSEEN" /
4024 ;; Above this line were in [IMAP2]
4025 "DRAFT" /
4026 "HEADER" SPACE header_fld_name SPACE astring /
4027 "LARGER" SPACE number / "NOT" SPACE search_key /
4028 "OR" SPACE search_key SPACE search_key /
4029 "SENTBEFORE" SPACE date / "SENTON" SPACE date /
4030 "SENTSINCE" SPACE date / "SMALLER" SPACE number /
4031
4032
4033
4034Crispin Standards Track [Page 72]
4035
4036RFC 2060 IMAP4rev1 December 1996
4037
4038
4039 "UID" SPACE set / "UNDRAFT" / set /
4040 "(" 1#search_key ")"
4041
4042section ::= "[" [section_text / (nz_number *["." nz_number]
4043 ["." (section_text / "MIME")])] "]"
4044
4045section_text ::= "HEADER" / "HEADER.FIELDS" [".NOT"]
4046 SPACE header_list / "TEXT"
4047
4048select ::= "SELECT" SPACE mailbox
4049
4050sequence_num ::= nz_number / "*"
4051 ;; * is the largest number in use. For message
4052 ;; sequence numbers, it is the number of messages
4053 ;; in the mailbox. For unique identifiers, it is
4054 ;; the unique identifier of the last message in
4055 ;; the mailbox.
4056
4057set ::= sequence_num / (sequence_num ":" sequence_num) /
4058 (set "," set)
4059 ;; Identifies a set of messages. For message
4060 ;; sequence numbers, these are consecutive
4061 ;; numbers from 1 to the number of messages in
4062 ;; the mailbox
4063 ;; Comma delimits individual numbers, colon
4064 ;; delimits between two numbers inclusive.
4065 ;; Example: 2,4:7,9,12:* is 2,4,5,6,7,9,12,13,
4066 ;; 14,15 for a mailbox with 15 messages.
4067
4068SPACE ::= <ASCII SP, space, 0x20>
4069
4070status ::= "STATUS" SPACE mailbox SPACE "(" 1#status_att ")"
4071
4072status_att ::= "MESSAGES" / "RECENT" / "UIDNEXT" / "UIDVALIDITY" /
4073 "UNSEEN"
4074
4075store ::= "STORE" SPACE set SPACE store_att_flags
4076
4077store_att_flags ::= (["+" / "-"] "FLAGS" [".SILENT"]) SPACE
4078 (flag_list / #flag)
4079
4080string ::= quoted / literal
4081
4082subscribe ::= "SUBSCRIBE" SPACE mailbox
4083
4084tag ::= 1*<any ATOM_CHAR except "+">
4085
4086text ::= 1*TEXT_CHAR
4087
4088
4089
4090Crispin Standards Track [Page 73]
4091
4092RFC 2060 IMAP4rev1 December 1996
4093
4094
4095text_mime2 ::= "=?" <charset> "?" <encoding> "?"
4096 <encoded-text> "?="
4097 ;; Syntax defined in [MIME-HDRS]
4098
4099TEXT_CHAR ::= <any CHAR except CR and LF>
4100
4101time ::= 2digit ":" 2digit ":" 2digit
4102 ;; Hours minutes seconds
4103
4104uid ::= "UID" SPACE (copy / fetch / search / store)
4105 ;; Unique identifiers used instead of message
4106 ;; sequence numbers
4107
4108uniqueid ::= nz_number
4109 ;; Strictly ascending
4110
4111unsubscribe ::= "UNSUBSCRIBE" SPACE mailbox
4112
4113userid ::= astring
4114
4115x_command ::= "X" atom <experimental command arguments>
4116
4117zone ::= ("+" / "-") 4digit
4118 ;; Signed four-digit value of hhmm representing
4119 ;; hours and minutes west of Greenwich (that is,
4120 ;; (the amount that the given time differs from
4121 ;; Universal Time). Subtracting the timezone
4122 ;; from the given time will give the UT form.
4123 ;; The Universal Time zone is "+0000".
4124
412510. Author's Note
4126
4127 This document is a revision or rewrite of earlier documents, and
4128 supercedes the protocol specification in those documents: RFC 1730,
4129 unpublished IMAP2bis.TXT document, RFC 1176, and RFC 1064.
4130
413111. Security Considerations
4132
4133 IMAP4rev1 protocol transactions, including electronic mail data, are
4134 sent in the clear over the network unless privacy protection is
4135 negotiated in the AUTHENTICATE command.
4136
4137 A server error message for an AUTHENTICATE command which fails due to
4138 invalid credentials SHOULD NOT detail why the credentials are
4139 invalid.
4140
4141 Use of the LOGIN command sends passwords in the clear. This can be
4142 avoided by using the AUTHENTICATE command instead.
4143
4144
4145
4146Crispin Standards Track [Page 74]
4147
4148RFC 2060 IMAP4rev1 December 1996
4149
4150
4151 A server error message for a failing LOGIN command SHOULD NOT specify
4152 that the user name, as opposed to the password, is invalid.
4153
4154 Additional security considerations are discussed in the section
4155 discussing the AUTHENTICATE and LOGIN commands.
4156
415712. Author's Address
4158
4159 Mark R. Crispin
4160 Networks and Distributed Computing
4161 University of Washington
4162 4545 15th Aveneue NE
4163 Seattle, WA 98105-4527
4164
4165 Phone: (206) 543-5762
4166
4167 EMail: MRC@CAC.Washington.EDU
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202Crispin Standards Track [Page 75]
4203
4204RFC 2060 IMAP4rev1 December 1996
4205
4206
4207Appendices
4208
4209A. References
4210
4211[ACAP] Myers, J. "ACAP -- Application Configuration Access Protocol",
4212Work in Progress.
4213
4214[CHARSET] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2,
4215RFC 1700, USC/Information Sciences Institute, October 1994.
4216
4217[DISPOSITION] Troost, R., and Dorner, S., "Communicating Presentation
4218Information in Internet Messages: The Content-Disposition Header",
4219RFC 1806, June 1995.
4220
4221[IMAP-AUTH] Myers, J., "IMAP4 Authentication Mechanism", RFC 1731.
4222Carnegie-Mellon University, December 1994.
4223
4224[IMAP-COMPAT] Crispin, M., "IMAP4 Compatibility with IMAP2bis", RFC
42252061, University of Washington, November 1996.
4226
4227[IMAP-DISC] Austein, R., "Synchronization Operations for Disconnected
4228IMAP4 Clients", Work in Progress.
4229
4230[IMAP-HISTORICAL] Crispin, M. "IMAP4 Compatibility with IMAP2 and
4231IMAP2bis", RFC 1732, University of Washington, December 1994.
4232
4233[IMAP-MODEL] Crispin, M., "Distributed Electronic Mail Models in
4234IMAP4", RFC 1733, University of Washington, December 1994.
4235
4236[IMAP-OBSOLETE] Crispin, M., "Internet Message Access Protocol -
4237Obsolete Syntax", RFC 2062, University of Washington, November 1996.
4238
4239[IMAP2] Crispin, M., "Interactive Mail Access Protocol - Version 2",
4240RFC 1176, University of Washington, August 1990.
4241
4242[LANGUAGE-TAGS] Alvestrand, H., "Tags for the Identification of
4243Languages", RFC 1766, March 1995.
4244
4245[MD5] Myers, J., and M. Rose, "The Content-MD5 Header Field", RFC
42461864, October 1995.
4247
4248[MIME-IMB] Freed, N., and N. Borenstein, "MIME (Multipurpose Internet
4249Mail Extensions) Part One: Format of Internet Message Bodies", RFC
42502045, November 1996.
4251
4252[MIME-IMT] Freed, N., and N. Borenstein, "MIME (Multipurpose
4253Internet Mail Extensions) Part Two: Media Types", RFC 2046,
4254November 1996.
4255
4256
4257
4258Crispin Standards Track [Page 76]
4259
4260RFC 2060 IMAP4rev1 December 1996
4261
4262
4263[MIME-HDRS] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
4264Part Three: Message Header Extensions for Non-ASCII Text", RFC
42652047, November 1996.
4266
4267[RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text
4268Messages", STD 11, RFC 822, University of Delaware, August 1982.
4269
4270[SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10,
4271RFC 821, USC/Information Sciences Institute, August 1982.
4272
4273[UTF-7] Goldsmith, D., and Davis, M., "UTF-7: A Mail-Safe
4274Transformation Format of Unicode", RFC 1642, July 1994.
4275
4276B. Changes from RFC 1730
4277
42781) The STATUS command has been added.
4279
42802) Clarify in the formal syntax that the "#" construct can never
4281refer to multiple spaces.
4282
42833) Obsolete syntax has been moved to a separate document.
4284
42854) The PARTIAL command has been obsoleted.
4286
42875) The RFC822.HEADER.LINES, RFC822.HEADER.LINES.NOT, RFC822.PEEK, and
4288RFC822.TEXT.PEEK fetch attributes have been obsoleted.
4289
42906) The "<" origin "." size ">" suffix for BODY text attributes has
4291been added.
4292
42937) The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, MIME, and TEXT part
4294specifiers have been added.
4295
42968) Support for Content-Disposition and Content-Language has been
4297added.
4298
42999) The restriction on fetching nested MULTIPART parts has been
4300removed.
4301
430210) Body part number 0 has been obsoleted.
4303
430411) Server-supported authenticators are now identified by
4305capabilities.
4306
4307
4308
4309
4310
4311
4312
4313
4314Crispin Standards Track [Page 77]
4315
4316RFC 2060 IMAP4rev1 December 1996
4317
4318
431912) The capability that identifies this protocol is now called
4320"IMAP4rev1". A server that provides backwards support for RFC 1730
4321SHOULD emit the "IMAP4" capability in addition to "IMAP4rev1" in its
4322CAPABILITY response. Because RFC-1730 required "IMAP4" to appear as
4323the first capability, it MUST listed first in the response.
4324
432513) A description of the mailbox name namespace convention has been
4326added.
4327
432814) A description of the international mailbox name convention has
4329been added.
4330
433115) The UID-NEXT and UID-VALIDITY status items are now called UIDNEXT
4332and UIDVALIDITY. This is a change from the IMAP STATUS
4333Work in Progress and not from RFC-1730
4334
433516) Add a clarification that a null mailbox name argument to the LIST
4336command returns an untagged LIST response with the hierarchy
4337delimiter and root of the reference argument.
4338
433917) Define terms such as "MUST", "SHOULD", and "MUST NOT".
4340
434118) Add a section which defines message attributes and more
4342thoroughly details the semantics of message sequence numbers, UIDs,
4343and flags.
4344
434519) Add a clarification detailing the circumstances when a client may
4346send multiple commands without waiting for a response, and the
4347circumstances in which ambiguities may result.
4348
434920) Add a recommendation on server behavior for DELETE and RENAME
4350when inferior hierarchical names of the given name exist.
4351
435221) Add a clarification that a mailbox name may not be unilaterally
4353unsubscribed by the server, even if that mailbox name no longer
4354exists.
4355
435622) Add a clarification that LIST should return its results quickly
4357without undue delay.
4358
435923) Add a clarification that the date_time argument to APPEND sets
4360the internal date of the message.
4361
436224) Add a clarification on APPEND behavior when the target mailbox is
4363the currently selected mailbox.
4364
4365
4366
4367
4368
4369
4370Crispin Standards Track [Page 78]
4371
4372RFC 2060 IMAP4rev1 December 1996
4373
4374
437525) Add a clarification that external changes to flags should be
4376always announced via an untagged FETCH even if the current command is
4377a STORE with the ".SILENT" suffix.
4378
437926) Add a clarification that COPY appends to the target mailbox.
4380
438127) Add the NEWNAME response code.
4382
438328) Rewrite the description of the untagged BYE response to clarify
4384its semantics.
4385
438629) Change the reference for the body MD5 to refer to the proper RFC.
4387
438830) Clarify that the formal syntax contains rules which may overlap,
4389and that in the event of such an overlap the rule which occurs first
4390takes precedence.
4391
439231) Correct the definition of body_fld_param.
4393
439432) More formal syntax for capability_data.
4395
439633) Clarify that any case variant of "INBOX" must be interpreted as
4397INBOX.
4398
439934) Clarify that the human-readable text in resp_text should not
4400begin with "[" or "=".
4401
440235) Change MIME references to Draft Standard documents.
4403
440436) Clarify \Recent semantics.
4405
440637) Additional examples.
4407
4408C. Key Word Index
4409
4410 +FLAGS <flag list> (store command data item) ............... 45
4411 +FLAGS.SILENT <flag list> (store command data item) ........ 46
4412 -FLAGS <flag list> (store command data item) ............... 46
4413 -FLAGS.SILENT <flag list> (store command data item) ........ 46
4414 ALERT (response code) ...................................... 50
4415 ALL (fetch item) ........................................... 41
4416 ALL (search key) ........................................... 38
4417 ANSWERED (search key) ...................................... 38
4418 APPEND (command) ........................................... 34
4419 AUTHENTICATE (command) ..................................... 20
4420 BAD (response) ............................................. 52
4421 BCC <string> (search key) .................................. 38
4422 BEFORE <date> (search key) ................................. 39
4423
4424
4425
4426Crispin Standards Track [Page 79]
4427
4428RFC 2060 IMAP4rev1 December 1996
4429
4430
4431 BODY (fetch item) .......................................... 41
4432 BODY (fetch result) ........................................ 58
4433 BODY <string> (search key) ................................. 39
4434 BODY.PEEK[<section>]<<partial>> (fetch item) ............... 44
4435 BODYSTRUCTURE (fetch item) ................................. 44
4436 BODYSTRUCTURE (fetch result) ............................... 59
4437 BODY[<section>]<<origin_octet>> (fetch result) ............. 58
4438 BODY[<section>]<<partial>> (fetch item) .................... 41
4439 BYE (response) ............................................. 52
4440 Body Structure (message attribute) ......................... 11
4441 CAPABILITY (command) ....................................... 18
4442 CAPABILITY (response) ...................................... 53
4443 CC <string> (search key) ................................... 39
4444 CHECK (command) ............................................ 36
4445 CLOSE (command) ............................................ 36
4446 COPY (command) ............................................. 46
4447 CREATE (command) ........................................... 25
4448 DELETE (command) ........................................... 26
4449 DELETED (search key) ....................................... 39
4450 DRAFT (search key) ......................................... 39
4451 ENVELOPE (fetch item) ...................................... 44
4452 ENVELOPE (fetch result) .................................... 62
4453 EXAMINE (command) .......................................... 24
4454 EXISTS (response) .......................................... 56
4455 EXPUNGE (command) .......................................... 37
4456 EXPUNGE (response) ......................................... 57
4457 Envelope Structure (message attribute) ..................... 11
4458 FAST (fetch item) .......................................... 44
4459 FETCH (command) ............................................ 41
4460 FETCH (response) ........................................... 58
4461 FLAGGED (search key) ....................................... 39
4462 FLAGS (fetch item) ......................................... 44
4463 FLAGS (fetch result) ....................................... 62
4464 FLAGS (response) ........................................... 56
4465 FLAGS <flag list> (store command data item) ................ 45
4466 FLAGS.SILENT <flag list> (store command data item) ......... 45
4467 FROM <string> (search key) ................................. 39
4468 FULL (fetch item) .......................................... 44
4469 Flags (message attribute) .................................. 9
4470 HEADER (part specifier) .................................... 41
4471 HEADER <field-name> <string> (search key) .................. 39
4472 HEADER.FIELDS <header_list> (part specifier) ............... 41
4473 HEADER.FIELDS.NOT <header_list> (part specifier) ........... 41
4474 INTERNALDATE (fetch item) .................................. 44
4475 INTERNALDATE (fetch result) ................................ 62
4476 Internal Date (message attribute) .......................... 10
4477 KEYWORD <flag> (search key) ................................ 39
4478 Keyword (type of flag) ..................................... 10
4479
4480
4481
4482Crispin Standards Track [Page 80]
4483
4484RFC 2060 IMAP4rev1 December 1996
4485
4486
4487 LARGER <n> (search key) .................................... 39
4488 LIST (command) ............................................. 30
4489 LIST (response) ............................................ 54
4490 LOGIN (command) ............................................ 22
4491 LOGOUT (command) ........................................... 20
4492 LSUB (command) ............................................. 32
4493 LSUB (response) ............................................ 55
4494 MAY (specification requirement term) ....................... 5
4495 MESSAGES (status item) ..................................... 33
4496 MIME (part specifier) ...................................... 42
4497 MUST (specification requirement term) ...................... 4
4498 MUST NOT (specification requirement term) .................. 4
4499 Message Sequence Number (message attribute) ................ 9
4500 NEW (search key) ........................................... 39
4501 NEWNAME (response code) .................................... 50
4502 NO (response) .............................................. 51
4503 NOOP (command) ............................................. 19
4504 NOT <search-key> (search key) .............................. 39
4505 OK (response) .............................................. 51
4506 OLD (search key) ........................................... 39
4507 ON <date> (search key) ..................................... 39
4508 OPTIONAL (specification requirement term) .................. 5
4509 OR <search-key1> <search-key2> (search key) ................ 39
4510 PARSE (response code) ...................................... 50
4511 PERMANENTFLAGS (response code) ............................. 50
4512 PREAUTH (response) ......................................... 52
4513 Permanent Flag (class of flag) ............................. 10
4514 READ-ONLY (response code) .................................. 50
4515 READ-WRITE (response code) ................................. 50
4516 RECENT (response) .......................................... 57
4517 RECENT (search key) ........................................ 39
4518 RECENT (status item) ....................................... 33
4519 RENAME (command) ........................................... 27
4520 REQUIRED (specification requirement term) .................. 4
4521 RFC822 (fetch item) ........................................ 44
4522 RFC822 (fetch result) ...................................... 63
4523 RFC822.HEADER (fetch item) ................................. 44
4524 RFC822.HEADER (fetch result) ............................... 62
4525 RFC822.SIZE (fetch item) ................................... 44
4526 RFC822.SIZE (fetch result) ................................. 62
4527 RFC822.TEXT (fetch item) ................................... 44
4528 RFC822.TEXT (fetch result) ................................. 62
4529 SEARCH (command) ........................................... 37
4530 SEARCH (response) .......................................... 55
4531 SEEN (search key) .......................................... 40
4532 SELECT (command) ........................................... 23
4533 SENTBEFORE <date> (search key) ............................. 40
4534 SENTON <date> (search key) ................................. 40
4535
4536
4537
4538Crispin Standards Track [Page 81]
4539
4540RFC 2060 IMAP4rev1 December 1996
4541
4542
4543 SENTSINCE <date> (search key) .............................. 40
4544 SHOULD (specification requirement term) .................... 5
4545 SHOULD NOT (specification requirement term) ................ 5
4546 SINCE <date> (search key) .................................. 40
4547 SMALLER <n> (search key) ................................... 40
4548 STATUS (command) ........................................... 33
4549 STATUS (response) .......................................... 55
4550 STORE (command) ............................................ 45
4551 SUBJECT <string> (search key) .............................. 40
4552 SUBSCRIBE (command) ........................................ 29
4553 Session Flag (class of flag) ............................... 10
4554 System Flag (type of flag) ................................. 9
4555 TEXT (part specifier) ...................................... 42
4556 TEXT <string> (search key) ................................. 40
4557 TO <string> (search key) ................................... 40
4558 TRYCREATE (response code) .................................. 51
4559 UID (command) .............................................. 47
4560 UID (fetch item) ........................................... 44
4561 UID (fetch result) ......................................... 63
4562 UID <message set> (search key) ............................. 40
4563 UIDNEXT (status item) ...................................... 33
4564 UIDVALIDITY (response code) ................................ 51
4565 UIDVALIDITY (status item) .................................. 34
4566 UNANSWERED (search key) .................................... 40
4567 UNDELETED (search key) ..................................... 40
4568 UNDRAFT (search key) ....................................... 40
4569 UNFLAGGED (search key) ..................................... 40
4570 UNKEYWORD <flag> (search key) .............................. 40
4571 UNSEEN (response code) ..................................... 51
4572 UNSEEN (search key) ........................................ 40
4573 UNSEEN (status item) ....................................... 34
4574 UNSUBSCRIBE (command) ...................................... 30
4575 Unique Identifier (UID) (message attribute) ................ 7
4576 X<atom> (command) .......................................... 48
4577 [RFC-822] Size (message attribute) ......................... 11
4578 \Answered (system flag) .................................... 9
4579 \Deleted (system flag) ..................................... 9
4580 \Draft (system flag) ....................................... 9
4581 \Flagged (system flag) ..................................... 9
4582 \Marked (mailbox name attribute) ........................... 54
4583 \Noinferiors (mailbox name attribute) ...................... 54
4584 \Noselect (mailbox name attribute) ......................... 54
4585 \Recent (system flag) ...................................... 10
4586 \Seen (system flag) ........................................ 9
4587 \Unmarked (mailbox name attribute) ......................... 54
4588
4589
4590
4591
4592
4593
4594Crispin Standards Track [Page 82]
4595
4596