7 Network Working Group M. Crispin
8 Request for Comments: 2060 University of Washington
9 Obsoletes: 1730 December 1996
10 Category: Standards Track
13 INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1
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.
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]).
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
40 IMAP4rev1 supports a single server. A mechanism for accessing
41 configuration information to support multiple IMAP4rev1 servers is
44 IMAP4rev1 does not specify a means of posting mail; this function is
45 handled by a mail transfer protocol such as [SMTP].
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48 unpublished IMAP2bis protocols.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].
58 Crispin Standards Track [Page 1]
60 RFC 2060 IMAP4rev1 December 1996
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.
71 IMAP4rev1 Protocol Specification .................................. 4
72 1. How to Read This Document ................................. 4
73 1.1. Organization of This Document ............................. 4
74 1.2. Conventions Used in This Document ......................... 4
75 2. Protocol Overview ......................................... 5
76 2.1. Link Level ................................................ 5
77 2.2. Commands and Responses .................................... 6
78 2.2.1. Client Protocol Sender and Server Protocol Receiver ....... 6
79 2.2.2. Server Protocol Sender and Client Protocol Receiver ....... 7
80 2.3. Message Attributes ........................................ 7
81 2.3.1. Message Numbers ........................................... 7
82 2.3.1.1. Unique Identifier (UID) Message Attribute ......... 7
83 2.3.1.2. Message Sequence Number Message Attribute ......... 9
84 2.3.2. Flags Message Attribute .................................... 9
85 2.3.3. Internal Date Message Attribute ........................... 10
86 2.3.4. [RFC-822] Size Message Attribute .......................... 11
87 2.3.5. Envelope Structure Message Attribute ...................... 11
88 2.3.6. Body Structure Message Attribute .......................... 11
89 2.4. Message Texts ............................................. 11
90 3. State and Flow Diagram .................................... 11
91 3.1. Non-Authenticated State ................................... 11
92 3.2. Authenticated State ....................................... 11
93 3.3. Selected State ............................................ 12
94 3.4. Logout State .............................................. 12
95 4. Data Formats .............................................. 12
96 4.1. Atom ...................................................... 13
97 4.2. Number .................................................... 13
98 4.3. String ..................................................... 13
99 4.3.1. 8-bit and Binary Strings .................................. 13
100 4.4. Parenthesized List ........................................ 14
101 4.5. NIL ....................................................... 14
102 5. Operational Considerations ................................ 14
103 5.1. Mailbox Naming ............................................ 14
104 5.1.1. Mailbox Hierarchy Naming .................................. 14
105 5.1.2. Mailbox Namespace Naming Convention ....................... 14
106 5.1.3. Mailbox International Naming Convention ................... 15
107 5.2. Mailbox Size and Message Status Updates ................... 16
108 5.3. Response when no Command in Progress ...................... 16
109 5.4. Autologout Timer .......................................... 16
110 5.5. Multiple Commands in Progress ............................. 17
114 Crispin Standards Track [Page 2]
116 RFC 2060 IMAP4rev1 December 1996
119 6. Client Commands ........................................... 17
120 6.1. Client Commands - Any State ............................... 18
121 6.1.1. CAPABILITY Command ........................................ 18
122 6.1.2. NOOP Command .............................................. 19
123 6.1.3. LOGOUT Command ............................................ 20
124 6.2. Client Commands - Non-Authenticated State ................. 20
125 6.2.1. AUTHENTICATE Command ...................................... 21
126 6.2.2. LOGIN Command ............................................. 22
127 6.3. Client Commands - Authenticated State ..................... 22
128 6.3.1. SELECT Command ............................................ 23
129 6.3.2. EXAMINE Command ........................................... 24
130 6.3.3. CREATE Command ............................................ 25
131 6.3.4. DELETE Command ............................................ 26
132 6.3.5. RENAME Command ............................................ 27
133 6.3.6. SUBSCRIBE Command ......................................... 29
134 6.3.7. UNSUBSCRIBE Command ....................................... 30
135 6.3.8. LIST Command .............................................. 30
136 6.3.9. LSUB Command .............................................. 32
137 6.3.10. STATUS Command ............................................ 33
138 6.3.11. APPEND Command ............................................ 34
139 6.4. Client Commands - Selected State .......................... 35
140 6.4.1. CHECK Command ............................................. 36
141 6.4.2. CLOSE Command ............................................. 36
142 6.4.3. EXPUNGE Command ........................................... 37
143 6.4.4. SEARCH Command ............................................ 37
144 6.4.5. FETCH Command ............................................. 41
145 6.4.6. STORE Command ............................................. 45
146 6.4.7. COPY Command .............................................. 46
147 6.4.8. UID Command ............................................... 47
148 6.5. Client Commands - Experimental/Expansion .................. 48
149 6.5.1. X<atom> Command ........................................... 48
150 7. Server Responses .......................................... 48
151 7.1. Server Responses - Status Responses ....................... 49
152 7.1.1. OK Response ............................................... 51
153 7.1.2. NO Response ............................................... 51
154 7.1.3. BAD Response .............................................. 52
155 7.1.4. PREAUTH Response .......................................... 52
156 7.1.5. BYE Response .............................................. 52
157 7.2. Server Responses - Server and Mailbox Status .............. 53
158 7.2.1. CAPABILITY Response ....................................... 53
159 7.2.2. LIST Response .............................................. 54
160 7.2.3. LSUB Response ............................................. 55
161 7.2.4 STATUS Response ........................................... 55
162 7.2.5. SEARCH Response ........................................... 55
163 7.2.6. FLAGS Response ............................................ 56
164 7.3. Server Responses - Mailbox Size ........................... 56
165 7.3.1. EXISTS Response ........................................... 56
166 7.3.2. RECENT Response ........................................... 57
170 Crispin Standards Track [Page 3]
172 RFC 2060 IMAP4rev1 December 1996
175 7.4. Server Responses - Message Status ......................... 57
176 7.4.1. EXPUNGE Response .......................................... 57
177 7.4.2. FETCH Response ............................................ 58
178 7.5. Server Responses - Command Continuation Request ........... 63
179 8. Sample IMAP4rev1 connection ............................... 63
180 9. Formal Syntax ............................................. 64
181 10. Author's Note ............................................. 74
182 11. Security Considerations ................................... 74
183 12. Author's Address .......................................... 75
184 Appendices ........................................................ 76
185 A. References ................................................ 76
186 B. Changes from RFC 1730 ..................................... 77
187 C. Key Word Index ............................................ 79
190 IMAP4rev1 Protocol Specification
192 1. How to Read This Document
194 1.1. Organization of This Document
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
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.
209 1.2. Conventions Used in This Document
211 In examples, "C:" and "S:" indicate lines sent by the client and
214 The following terms are used in this document to signify the
215 requirements of this specification.
217 1) MUST, or the adjective REQUIRED, means that the definition is
218 an absolute requirement of the specification.
220 2) MUST NOT that the definition is an absolute prohibition of the
226 Crispin Standards Track [Page 4]
228 RFC 2060 IMAP4rev1 December 1996
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.
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.
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.
250 "Can" is used instead of "may" when referring to a possible
251 circumstance or situation, as opposed to an optional facility of
254 "User" is used to refer to a human user, whereas "client" refers
255 to the software being run by the user.
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).
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.
275 The IMAP4rev1 protocol assumes a reliable data stream such as
276 provided by TCP. When TCP is used, an IMAP4rev1 server listens on
282 Crispin Standards Track [Page 5]
284 RFC 2060 IMAP4rev1 December 1996
287 2.2. Commands and Responses
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.
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.
300 2.2.1. Client Protocol Sender and Server Protocol Receiver
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.
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 "+".
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.
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.
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.
338 Crispin Standards Track [Page 6]
340 RFC 2060 IMAP4rev1 December 1996
343 2.2.2. Server Protocol Sender and Client Protocol Receiver
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.
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.
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).
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 "+".
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.
373 This topic is discussed in greater detail in the Server Responses
376 2.3. Message Attributes
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.
382 2.3.1. Message Numbers
384 Messages in IMAP4rev1 are accessed by one of two numbers; the unique
385 identifier and the message sequence number.
387 2.3.1.1. Unique Identifier (UID) Message Attribute
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
394 Crispin Standards Track [Page 7]
396 RFC 2060 IMAP4rev1 December 1996
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
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].
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
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.
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.
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
450 Crispin Standards Track [Page 8]
452 RFC 2060 IMAP4rev1 December 1996
455 2.3.1.2. Message Sequence Number Message Attribute
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.
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
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.
479 2.3.2. Flags Message Attribute
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.
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:
491 \Seen Message has been read
493 \Answered Message has been answered
495 \Flagged Message is "flagged" for urgent/special attention
497 \Deleted Message is "deleted" for removal by later EXPUNGE
499 \Draft Message has not completed composition (marked as a
506 Crispin Standards Track [Page 9]
508 RFC 2060 IMAP4rev1 December 1996
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.
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
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
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).
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.
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.
543 2.3.3. Internal Date Message Attribute
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.
562 Crispin Standards Track [Page 10]
564 RFC 2060 IMAP4rev1 December 1996
567 2.3.4. [RFC-822] Size Message Attribute
569 The number of octets in the message, as expressed in [RFC-822]
572 2.3.5. Envelope Structure Message Attribute
574 A parsed representation of the [RFC-822] envelope information (not to
575 be confused with an [SMTP] envelope) of the message.
577 2.3.6. Body Structure Message Attribute
579 A parsed representation of the [MIME-IMB] body structure information
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
590 3. State and Flow Diagram
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.
598 3.1. Non-Authenticated State
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-
605 3.2. Authenticated State
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.
618 Crispin Standards Track [Page 11]
620 RFC 2060 IMAP4rev1 December 1996
625 In selected state, a mailbox has been selected to access. This state
626 is entered when a mailbox has been successfully selected.
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.
634 +--------------------------------------+
635 |initial connection and server greeting|
636 +--------------------------------------+
639 +-----------------+ || ||
640 |non-authenticated| || ||
641 +-----------------+ || ||
644 || +----------------+ ||
645 || | authenticated |<=++ ||
646 || +----------------+ || ||
647 || || (7) || (5) || (6) ||
649 || || +--------+ || ||
650 || || |selected|==++ ||
654 +--------------------------------------+
655 | logout and close connection |
656 +--------------------------------------+
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
668 IMAP4rev1 uses textual commands and responses. Data in IMAP4rev1 can
669 be in one of several forms: atom, number, string, parenthesized list,
674 Crispin Standards Track [Page 12]
676 RFC 2060 IMAP4rev1 December 1996
681 An atom consists of one or more non-special characters.
685 A number consists of one or more digit characters, and represents a
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
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).
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.
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).
712 Note: Even if the octet count is 0, a client transmitting a
713 literal MUST wait to receive a command continuation request.
715 4.3.1. 8-bit and Binary Strings
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.
730 Crispin Standards Track [Page 13]
732 RFC 2060 IMAP4rev1 December 1996
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
742 4.4. Parenthesized List
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.
749 The empty list is represented as () -- a parenthesized list with no
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 ().
758 5. Operational Considerations
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".
766 5.1.1. Mailbox Hierarchy Naming
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.
773 5.1.2. Mailbox Namespace Naming Convention
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.
786 Crispin Standards Track [Page 14]
788 RFC 2060 IMAP4rev1 December 1996
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).
798 5.1.3. Mailbox International Naming Convention
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
805 1) UTF-7 uses the "+" character for shifting; this conflicts with
806 the common use of "+" in mailbox names, in particular USENET
809 2) UTF-7's encoding is BASE64 which uses the "/" character; this
810 conflicts with the use of "/" as a popular hierarchy delimiter.
812 3) UTF-7 prohibits the unencoded usage of "\"; this conflicts with
813 the use of "\" as a popular hierarchy delimiter.
815 4) UTF-7 prohibits the unencoded usage of "~"; this conflicts with
816 the use of "~" in some servers as a home directory indicator.
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.
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-
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.
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 "-
842 Crispin Standards Track [Page 15]
844 RFC 2060 IMAP4rev1 December 1996
847 For example, here is a mailbox name which mixes English, Japanese,
848 and Chinese text: ~peter/mail/&ZeVnLIqe-/&U,BTFw-
850 5.2. Mailbox Size and Message Status Updates
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.
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.
870 5.3. Response when no Command in Progress
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.
879 5.4. Autologout Timer
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
898 Crispin Standards Track [Page 16]
900 RFC 2060 IMAP4rev1 December 1996
903 5.5. Multiple Commands in Progress
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.
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.
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.
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
934 For example, the following non-waiting command sequences are invalid:
941 The following are examples of valid non-waiting command sequences:
943 FETCH + STORE + SEARCH + CHECK
944 STORE + COPY + EXPUNGE
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
954 Crispin Standards Track [Page 17]
956 RFC 2060 IMAP4rev1 December 1996
959 permitted state (for example, commands valid in authenticated and
960 selected state are listed in the authenticated state commands).
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
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".
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.
980 6.1. Client Commands - Any State
982 The following commands are valid in any state: CAPABILITY, NOOP, and
985 6.1.1. CAPABILITY Command
989 Responses: REQUIRED untagged response: CAPABILITY
991 Result: OK - capability completed
992 BAD - command unknown or arguments invalid
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.
1010 Crispin Standards Track [Page 18]
1012 RFC 2060 IMAP4rev1 December 1996
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".
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.
1028 See the section entitled "Client Commands -
1029 Experimental/Expansion" for information about the form of site or
1030 implementation-specific capabilities.
1032 Example: C: abcd CAPABILITY
1033 S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4
1034 S: abcd OK CAPABILITY completed
1040 Responses: no specific responses for this command (but see below)
1042 Result: OK - noop completed
1043 BAD - command unknown or arguments invalid
1045 The NOOP command always succeeds. It does nothing.
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
1053 Example: C: a002 NOOP
1054 S: a002 OK NOOP completed
1060 S: * 14 FETCH (FLAGS (\Seen \Deleted))
1061 S: a047 OK NOOP completed
1066 Crispin Standards Track [Page 19]
1068 RFC 2060 IMAP4rev1 December 1996
1071 6.1.3. LOGOUT Command
1075 Responses: REQUIRED untagged response: BYE
1077 Result: OK - logout completed
1078 BAD - command unknown or arguments invalid
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
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)
1090 6.2. Client Commands - Non-Authenticated State
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.
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.
1104 Once authenticated (including as anonymous), it is not possible to
1105 re-enter non-authenticated state.
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.
1122 Crispin Standards Track [Page 20]
1124 RFC 2060 IMAP4rev1 December 1996
1127 6.2.1. AUTHENTICATE Command
1129 Arguments: authentication mechanism name
1131 Responses: continuation data can be requested
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
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.
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.
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.
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
1178 Crispin Standards Track [Page 21]
1180 RFC 2060 IMAP4rev1 December 1996
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
1189 Example: S: * OK KerberosV4 IMAP4rev1 Server
1190 C: A001 AUTHENTICATE KERBEROS_V4
1192 C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
1193 +nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd
1194 WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh
1196 C: DiAF5A4gA+oOIALuBkAAmw==
1197 S: A001 OK Kerberos V4 authentication successful
1199 Note: the line breaks in the first client answer are for editorial
1200 clarity and are not in real authenticators.
1202 6.2.2. LOGIN Command
1204 Arguments: user name
1207 Responses: no specific responses for this command
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
1213 The LOGIN command identifies the client to the server and carries
1214 the plaintext password authenticating this user.
1216 Example: C: a001 LOGIN SMITH SESAME
1217 S: a001 OK LOGIN completed
1219 6.3. Client Commands - Authenticated State
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.
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,
1234 Crispin Standards Track [Page 22]
1236 RFC 2060 IMAP4rev1 December 1996
1239 6.3.1. SELECT Command
1241 Arguments: mailbox name
1243 Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT
1244 OPTIONAL OK untagged responses: UNSEEN, PERMANENTFLAGS
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
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:
1255 FLAGS Defined flags in the mailbox. See the description
1256 of the FLAGS response for more detail.
1258 <n> EXISTS The number of messages in the mailbox. See the
1259 description of the EXISTS response for more detail.
1261 <n> RECENT The number of messages with the \Recent flag set.
1262 See the description of the RECENT response for more
1265 OK [UIDVALIDITY <n>]
1266 The unique identifier validity value. See the
1267 description of the UID command for more detail.
1269 to define the initial state of the mailbox at the client.
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.
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.
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.
1290 Crispin Standards Track [Page 23]
1292 RFC 2060 IMAP4rev1 December 1996
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.
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.
1309 Example: C: A142 SELECT INBOX
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
1318 6.3.2. EXAMINE Command
1320 Arguments: mailbox name
1322 Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT
1323 OPTIONAL OK untagged responses: UNSEEN, PERMANENTFLAGS
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
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.
1346 Crispin Standards Track [Page 24]
1348 RFC 2060 IMAP4rev1 December 1996
1351 The text of the tagged OK response to the EXAMINE command MUST
1352 begin with the "[READ-ONLY]" response code.
1354 Example: C: A932 EXAMINE blurdybloop
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
1363 6.3.3. CREATE Command
1365 Arguments: mailbox name
1367 Responses: no specific responses for this command
1369 Result: OK - create completed
1370 NO - create failure: can't create mailbox with that name
1371 BAD - command unknown or arguments invalid
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.
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
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.
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
1402 Crispin Standards Track [Page 25]
1404 RFC 2060 IMAP4rev1 December 1996
1407 Example: C: A003 CREATE owatagusiam/
1408 S: A003 OK CREATE completed
1409 C: A004 CREATE owatagusiam/blurdybloop
1410 S: A004 OK CREATE completed
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.
1418 6.3.4. DELETE Command
1420 Arguments: mailbox name
1422 Responses: no specific responses for this command
1424 Result: OK - delete completed
1425 NO - delete failure: can't delete mailbox with that name
1426 BAD - command unknown or arguments invalid
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.
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).
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.
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
1458 Crispin Standards Track [Page 26]
1460 RFC 2060 IMAP4rev1 December 1996
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
1471 S: A684 NO Name "foo" has inferior hierarchical names
1472 C: A685 DELETE foo/bar
1473 S: A685 OK DELETE Completed
1475 S: * LIST (\Noselect) "/" foo
1476 S: A686 OK LIST completed
1478 S: A687 OK DELETE Completed
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
1489 S: A84 OK DELETE Completed
1491 S: * LIST () "." foo.bar
1492 S: A85 OK LIST completed
1494 S: * LIST (\Noselect) "." foo
1495 S: A86 OK LIST completed
1497 6.3.5. RENAME Command
1499 Arguments: existing mailbox name
1502 Responses: no specific responses for this command
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
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
1514 Crispin Standards Track [Page 27]
1516 RFC 2060 IMAP4rev1 December 1996
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.
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".
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
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
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
1551 S: * LIST () "/" sarasoop
1552 S: * LIST (\Noselect) "/" zowie
1553 S: * LIST () "/" zowie/bar
1554 S: A685 OK LIST completed
1570 Crispin Standards Track [Page 28]
1572 RFC 2060 IMAP4rev1 December 1996
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
1582 S: * LIST () "." INBOX
1583 S: * LIST () "." INBOX.bar
1584 S: * LIST () "." old-mail
1585 S: Z434 OK LIST completed
1587 6.3.6. SUBSCRIBE Command
1591 Responses: no specific responses for this command
1593 Result: OK - subscribe completed
1594 NO - subscribe failure: can't subscribe to that name
1595 BAD - command unknown or arguments invalid
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.
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.
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.
1612 Example: C: A002 SUBSCRIBE #news.comp.mail.mime
1613 S: A002 OK SUBSCRIBE completed
1626 Crispin Standards Track [Page 29]
1628 RFC 2060 IMAP4rev1 December 1996
1631 6.3.7. UNSUBSCRIBE Command
1633 Arguments: mailbox name
1635 Responses: no specific responses for this command
1637 Result: OK - unsubscribe completed
1638 NO - unsubscribe failure: can't unsubscribe that name
1639 BAD - command unknown or arguments invalid
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.
1646 Example: C: A002 UNSUBSCRIBE #news.comp.mail.mime
1647 S: A002 OK UNSUBSCRIBE completed
1649 6.3..8. LIST Command
1651 Arguments: reference name
1652 mailbox name with possible wildcards
1654 Responses: untagged responses: LIST
1656 Result: OK - list completed
1657 NO - list failure: can't list that reference or name
1658 BAD - command unknown or arguments invalid
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
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!
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.
1682 Crispin Standards Track [Page 30]
1684 RFC 2060 IMAP4rev1 December 1996
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
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.
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.
1710 For example, here are some examples of how references and mailbox
1711 names might be interpreted on a UNIX-based server:
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/*
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.
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).
1738 Crispin Standards Track [Page 31]
1740 RFC 2060 IMAP4rev1 December 1996
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
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.
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
1774 Arguments: reference name
1775 mailbox name with possible wildcards
1777 Responses: untagged responses: LSUB
1779 Result: OK - lsub completed
1780 NO - lsub failure: can't list that reference or name
1781 BAD - command unknown or arguments invalid
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.
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
1794 Crispin Standards Track [Page 32]
1796 RFC 2060 IMAP4rev1 December 1996
1799 unilaterally remove an existing mailbox name from the subscription
1800 list even if a mailbox by that name no longer exists.
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
1807 6.3.10. STATUS Command
1809 Arguments: mailbox name
1810 status data item names
1812 Responses: untagged responses: STATUS
1814 Result: OK - status completed
1815 NO - status failure: no status for that name
1816 BAD - command unknown or arguments invalid
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
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.
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.
1835 The currently defined status data items that can be requested are:
1837 MESSAGES The number of messages in the mailbox.
1839 RECENT The number of messages with the \Recent flag set.
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.
1850 Crispin Standards Track [Page 33]
1852 RFC 2060 IMAP4rev1 December 1996
1855 UIDVALIDITY The unique identifier validity value of the
1858 UNSEEN The number of messages which do not have the \Seen
1862 Example: C: A042 STATUS blurdybloop (UIDNEXT MESSAGES)
1863 S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
1864 S: A042 OK STATUS completed
1866 6.3.11. APPEND Command
1868 Arguments: mailbox name
1869 OPTIONAL flag parenthesized list
1870 OPTIONAL date/time string
1873 Responses: no specific responses for this command
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
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
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.
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.
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.
1906 Crispin Standards Track [Page 34]
1908 RFC 2060 IMAP4rev1 December 1996
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
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
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.
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
1938 C: Hello Joe, do you think we can meet at 3:30 tomorrow?
1940 S: A003 OK APPEND completed
1942 Note: the APPEND command is not used for message delivery, because
1943 it does not provide a mechanism to transfer [SMTP] envelope
1946 6.4. Client Commands - Selected State
1948 In selected state, commands that manipulate messages in a mailbox are
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.
1962 Crispin Standards Track [Page 35]
1964 RFC 2060 IMAP4rev1 December 1996
1967 6.4.1. CHECK Command
1971 Responses: no specific responses for this command
1973 Result: OK - check completed
1974 BAD - command unknown or arguments invalid
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.
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
1989 Example: C: FXXZ CHECK
1990 S: FXXZ OK CHECK Completed
1992 6.4.2. CLOSE Command
1996 Responses: no specific responses for this command
1998 Result: OK - close completed, now in authenticated state
1999 NO - close failure: no mailbox selected
2000 BAD - command unknown or arguments invalid
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
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.
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
2018 Crispin Standards Track [Page 36]
2020 RFC 2060 IMAP4rev1 December 1996
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.
2027 Example: C: A341 CLOSE
2028 S: A341 OK CLOSE completed
2030 6.4.3. EXPUNGE Command
2034 Responses: untagged responses: EXPUNGE
2036 Result: OK - expunge completed
2037 NO - expunge failure: can't expunge (e.g. permission
2039 BAD - command unknown or arguments invalid
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.
2046 Example: C: A202 EXPUNGE
2051 S: A202 OK EXPUNGE completed
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.
2057 6.4.4. SEARCH Command
2059 Arguments: OPTIONAL [CHARSET] specification
2060 searching criteria (one or more)
2062 Responses: REQUIRED untagged response: SEARCH
2064 Result: OK - search completed
2065 NO - search error: can't search that [CHARSET] or
2067 BAD - command unknown or arguments invalid
2074 Crispin Standards Track [Page 37]
2076 RFC 2060 IMAP4rev1 December 1996
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.
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
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.
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).
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-
2111 The defined search keys are as follows. Refer to the Formal
2112 Syntax section for the precise syntactic definitions of the
2115 <message set> Messages with message sequence numbers
2116 corresponding to the specified message sequence
2119 ALL All messages in the mailbox; the default initial
2122 ANSWERED Messages with the \Answered flag set.
2124 BCC <string> Messages that contain the specified string in the
2125 envelope structure's BCC field.
2130 Crispin Standards Track [Page 38]
2132 RFC 2060 IMAP4rev1 December 1996
2135 BEFORE <date> Messages whose internal date is earlier than the
2138 BODY <string> Messages that contain the specified string in the
2139 body of the message.
2141 CC <string> Messages that contain the specified string in the
2142 envelope structure's CC field.
2144 DELETED Messages with the \Deleted flag set.
2146 DRAFT Messages with the \Draft flag set.
2148 FLAGGED Messages with the \Flagged flag set.
2150 FROM <string> Messages that contain the specified string in the
2151 envelope structure's FROM field.
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]
2159 KEYWORD <flag> Messages with the specified keyword set.
2161 LARGER <n> Messages with an [RFC-822] size larger than the
2162 specified number of octets.
2164 NEW Messages that have the \Recent flag set but not the
2165 \Seen flag. This is functionally equivalent to
2169 Messages that do not match the specified search
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").
2176 ON <date> Messages whose internal date is within the
2179 OR <search-key1> <search-key2>
2180 Messages that match either search key.
2182 RECENT Messages that have the \Recent flag set.
2186 Crispin Standards Track [Page 39]
2188 RFC 2060 IMAP4rev1 December 1996
2191 SEEN Messages that have the \Seen flag set.
2194 Messages whose [RFC-822] Date: header is earlier
2195 than the specified date.
2197 SENTON <date> Messages whose [RFC-822] Date: header is within the
2201 Messages whose [RFC-822] Date: header is within or
2202 later than the specified date.
2204 SINCE <date> Messages whose internal date is within or later
2205 than the specified date.
2207 SMALLER <n> Messages with an [RFC-822] size smaller than the
2208 specified number of octets.
2211 Messages that contain the specified string in the
2212 envelope structure's SUBJECT field.
2214 TEXT <string> Messages that contain the specified string in the
2215 header or body of the message.
2217 TO <string> Messages that contain the specified string in the
2218 envelope structure's TO field.
2221 Messages with unique identifiers corresponding to
2222 the specified unique identifier set.
2224 UNANSWERED Messages that do not have the \Answered flag set.
2226 UNDELETED Messages that do not have the \Deleted flag set.
2228 UNDRAFT Messages that do not have the \Draft flag set.
2230 UNFLAGGED Messages that do not have the \Flagged flag set.
2233 Messages that do not have the specified keyword
2236 UNSEEN Messages that do not have the \Seen flag set.
2242 Crispin Standards Track [Page 40]
2244 RFC 2060 IMAP4rev1 December 1996
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
2251 6.4.5. FETCH Command
2253 Arguments: message set
2254 message data item names
2256 Responses: untagged responses: FETCH
2258 Result: OK - fetch completed
2259 NO - fetch error: can't fetch that data
2260 BAD - command unknown or arguments invalid
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.
2266 The currently defined data items that can be fetched are:
2268 ALL Macro equivalent to: (FLAGS INTERNALDATE
2269 RFC822.SIZE ENVELOPE)
2271 BODY Non-extensible form of BODYSTRUCTURE.
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.
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,
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.
2298 Crispin Standards Track [Page 41]
2300 RFC 2060 IMAP4rev1 December 1996
2303 A part of type MESSAGE/RFC822 also has nested part
2304 numbers, referring to parts of the MESSAGE part's
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.
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.
2331 The MIME part specifier refers to the [MIME-IMB]
2332 header for this part.
2334 The TEXT part specifier refers to the text body of
2335 the message, omitting the [RFC-822] header.
2354 Crispin Standards Track [Page 42]
2356 RFC 2060 IMAP4rev1 December 1996
2359 Here is an example of a complex message
2360 with some of its part specifiers:
2362 HEADER ([RFC-822] header of the message)
2363 TEXT MULTIPART/MIXED
2365 2 APPLICATION/OCTET-STREAM
2367 3.HEADER ([RFC-822] header of the message)
2368 3.TEXT ([RFC-822] text body of the message)
2370 3.2 APPLICATION/OCTET-STREAM
2373 4.1.MIME ([MIME-IMB] header for the IMAGE/GIF)
2375 4.2.HEADER ([RFC-822] header of the message)
2376 4.2.TEXT ([RFC-822] text body of the message)
2378 4.2.2 MULTIPART/ALTERNATIVE
2380 4.2.2.2 TEXT/RICHTEXT
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
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.
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[].
2401 Note: a substring fetch of a
2402 HEADER.FIELDS or HEADER.FIELDS.NOT part
2403 specifier is calculated after subsetting
2410 Crispin Standards Track [Page 43]
2412 RFC 2060 IMAP4rev1 December 1996
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.
2419 BODY.PEEK[<section>]<<partial>>
2420 An alternate form of BODY[<section>] that does not
2421 implicitly set the \Seen flag.
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
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.
2433 FAST Macro equivalent to: (FLAGS INTERNALDATE
2436 FLAGS The flags that are set for this message.
2438 FULL Macro equivalent to: (FLAGS INTERNALDATE
2439 RFC822.SIZE ENVELOPE BODY)
2441 INTERNALDATE The internal date of the message.
2443 RFC822 Functionally equivalent to BODY[], differing in the
2444 syntax of the resulting untagged FETCH data (RFC822
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).
2451 RFC822.SIZE The [RFC-822] size of the message.
2453 RFC822.TEXT Functionally equivalent to BODY[TEXT], differing in
2454 the syntax of the resulting untagged FETCH data
2455 (RFC822.TEXT is returned).
2457 UID The unique identifier for the message.
2466 Crispin Standards Track [Page 44]
2468 RFC 2060 IMAP4rev1 December 1996
2471 Example: C: A654 FETCH 2:4 (FLAGS BODY[HEADER.FIELDS (DATE FROM)])
2475 S: A654 OK FETCH completed
2477 6.4.6. STORE Command
2479 Arguments: message set
2480 message data item name
2481 value for message data item
2483 Responses: untagged responses: FETCH
2485 Result: OK - store completed
2486 NO - store error: can't store that data
2487 BAD - command unknown or arguments invalid
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.
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.
2502 The currently defined data items that can be stored are:
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.
2509 FLAGS.SILENT <flag list>
2510 Equivalent to FLAGS, but without returning a new
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.
2522 Crispin Standards Track [Page 45]
2524 RFC 2060 IMAP4rev1 December 1996
2527 +FLAGS.SILENT <flag list>
2528 Equivalent to +FLAGS, but without returning a new
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.
2536 -FLAGS.SILENT <flag list>
2537 Equivalent to -FLAGS, but without returning a new
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
2548 Arguments: message set
2551 Responses: no specific responses for this command
2553 Result: OK - copy completed
2554 NO - copy error: can't copy those messages or to that
2556 BAD - command unknown or arguments invalid
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.
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.
2578 Crispin Standards Track [Page 46]
2580 RFC 2060 IMAP4rev1 December 1996
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.
2587 Example: C: A003 COPY 2:4 MEETING
2588 S: A003 OK COPY completed
2592 Arguments: command name
2595 Responses: untagged responses: FETCH, SEARCH
2597 Result: OK - UID command completed
2598 NO - UID command error
2599 BAD - command unknown or arguments invalid
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
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
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
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.
2634 Crispin Standards Track [Page 47]
2636 RFC 2060 IMAP4rev1 December 1996
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
2645 6.5. Client Commands - Experimental/Expansion
2647 6.5.1. X<atom> Command
2649 Arguments: implementation defined
2651 Responses: implementation defined
2653 Result: OK - command completed
2655 BAD - command unknown or arguments invalid
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.
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.
2667 Example: C: a441 CAPABILITY
2668 S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4 XPIG-LATIN
2669 S: a441 OK CAPABILITY completed
2671 S: * XPIG-LATIN ow-nay eaking-spay ig-pay atin-lay
2672 S: A442 OK XPIG-LATIN ompleted-cay
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
2683 The client MUST be prepared to accept any response at all times.
2690 Crispin Standards Track [Page 48]
2692 RFC 2060 IMAP4rev1 December 1996
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.
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".
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).
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.
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
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
2735 7.1. Server Responses - Status Responses
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.
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
2746 Crispin Standards Track [Page 49]
2748 RFC 2060 IMAP4rev1 December 1996
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
2756 The currently defined response codes are:
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.
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
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.
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.
2788 READ-ONLY The mailbox is selected read-only, or its access
2789 while selected has changed from read-write to
2792 READ-WRITE The mailbox is selected read-write, or its access
2793 while selected has changed from read-only to
2802 Crispin Standards Track [Page 50]
2804 RFC 2060 IMAP4rev1 December 1996
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.
2813 UIDVALIDITY Followed by a decimal number, indicates the unique
2814 identifier validity value.
2816 UNSEEN Followed by a decimal number, indicates the number
2817 of the first message without the \Seen flag set.
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.
2826 Contents: OPTIONAL response code
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.
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.
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
2847 Contents: OPTIONAL response code
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.
2858 Crispin Standards Track [Page 51]
2860 RFC 2060 IMAP4rev1 December 1996
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
2873 Contents: OPTIONAL response code
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.
2883 Example: C: ...very long command line...
2884 S: * BAD Command line too long
2886 S: * BAD Empty command line
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
2892 7.1.4. PREAUTH Response
2894 Contents: OPTIONAL response code
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.
2902 Example: S: * PREAUTH IMAP4rev1 server logged in as Smith
2906 Contents: OPTIONAL response code
2914 Crispin Standards Track [Page 52]
2916 RFC 2060 IMAP4rev1 December 1996
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:
2924 1) as part of a normal logout sequence. The server will close
2925 the connection after sending the tagged OK response to the
2928 2) as a panic shutdown announcement. The server closes the
2929 connection immediately.
2931 3) as an announcement of an inactivity autologout. The server
2932 closes the connection immediately.
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.
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.
2944 Example: S: * BYE Autologout; idle for too long
2946 7.2. Server Responses - Server and Mailbox Status
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.
2952 7.2.1. CAPABILITY Response
2954 Contents: capability listing
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".
2961 A capability name which begins with "AUTH=" indicates that the
2962 server supports that particular authentication mechanism.
2970 Crispin Standards Track [Page 53]
2972 RFC 2060 IMAP4rev1 December 1996
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.
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
2986 Client implementations SHOULD NOT require any capability name
2987 other than "IMAP4rev1", and MUST ignore any unknown capability
2990 Example: S: * CAPABILITY IMAP4rev1 AUTH=KERBEROS_V4 XPIG-LATIN
2992 7.2.2. LIST Response
2994 Contents: name attributes
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.
3002 Four name attributes are defined:
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.
3008 \Noselect It is not possible to use this name as a selectable
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
3016 \Unmarked The mailbox does not contain any additional
3017 messages since the last time the mailbox was
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.
3026 Crispin Standards Track [Page 54]
3028 RFC 2060 IMAP4rev1 December 1996
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.
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
3044 Example: S: * LIST (\Noselect) "/" ~/Mail/foo
3046 7.2.3. LSUB Response
3048 Contents: name attributes
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.
3057 Example: S: * LSUB () "." #news.comp.mail.misc
3059 7.2.4 STATUS Response
3062 status parenthesized list
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.
3068 Example: S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
3070 7.2.5. SEARCH Response
3072 Contents: zero or more numbers
3082 Crispin Standards Track [Page 55]
3084 RFC 2060 IMAP4rev1 December 1996
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.
3093 Example: S: * SEARCH 2 3 6
3095 7.2.6. FLAGS Response
3097 Contents: flag parenthesized list
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.
3105 The update from the FLAGS response MUST be recorded by the client.
3107 Example: S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
3109 7.3. Server Responses - Mailbox Size
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
3116 7.3.1. EXISTS Response
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).
3124 The update from the EXISTS response MUST be recorded by the
3127 Example: S: * 23 EXISTS
3138 Crispin Standards Track [Page 56]
3140 RFC 2060 IMAP4rev1 December 1996
3143 7.3.2. RECENT Response
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
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.
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
3165 The update from the RECENT response MUST be recorded by the
3168 Example: S: * 5 RECENT
3170 7.4. Server Responses - Message Status
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.
3177 7.4.1. EXPUNGE Response
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).
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
3194 Crispin Standards Track [Page 57]
3196 RFC 2060 IMAP4rev1 December 1996
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.
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
3212 The update from the EXPUNGE response MUST be recorded by the
3215 Example: S: * 44 EXPUNGE
3217 7.4.2. FETCH Response
3219 Contents: message data
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
3227 The current data items are:
3229 BODY A form of BODYSTRUCTURE without extension data.
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.
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.
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
3250 Crispin Standards Track [Page 58]
3252 RFC 2060 IMAP4rev1 December 1996
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.
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.
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.
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
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,
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"))
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
3296 The extension data of a multipart body part are in
3297 the following order:
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
3306 Crispin Standards Track [Page 59]
3308 RFC 2060 IMAP4rev1 December 1996
3311 "baz"] as defined in [MIME-IMB].
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].
3322 A string or parenthesized list giving the body
3323 language value as defined in [LANGUAGE-TAGS].
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.
3335 The basic fields of a non-multipart body part are
3336 in the following order:
3339 A string giving the content media type name as
3340 defined in [MIME-IMB].
3343 A string giving the content subtype name as
3344 defined in [MIME-IMB].
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].
3353 A string giving the content id as defined in
3357 A string giving the content description as
3358 defined in [MIME-IMB].
3362 Crispin Standards Track [Page 60]
3364 RFC 2060 IMAP4rev1 December 1996
3368 A string giving the content transfer encoding as
3369 defined in [MIME-IMB].
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
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.
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.
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.
3394 The extension data of a non-multipart body part are
3395 in the following order:
3398 A string giving the body MD5 value as defined in
3402 A parenthesized list with the same content and
3403 function as the body disposition for a multipart
3407 A string or parenthesized list giving the body
3408 language value as defined in [LANGUAGE-TAGS].
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.
3418 Crispin Standards Track [Page 61]
3420 RFC 2060 IMAP4rev1 December 1996
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
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
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.
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.
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.
3457 FLAGS A parenthesized list of flags that are set for this
3460 INTERNALDATE A string representing the internal date of the
3463 RFC822 Equivalent to BODY[].
3465 RFC822.HEADER Equivalent to BODY.PEEK[HEADER].
3467 RFC822.SIZE A number expressing the [RFC-822] size of the
3470 RFC822.TEXT Equivalent to BODY[TEXT].
3474 Crispin Standards Track [Page 62]
3476 RFC 2060 IMAP4rev1 December 1996
3479 UID A number expressing the unique identifier of the
3483 Example: S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827)
3485 7.5. Server Responses - Command Continuation Request
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.
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.
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.
3504 Example: C: A001 LOGIN {11}
3505 S: + Ready for additional command text
3507 S: + Ready for additional command text
3509 S: A001 OK LOGIN completed
3510 C: A044 BLURDYBLOOP {102856}
3511 S: A044 BAD No such command as "BLURDYBLOOP"
3513 8. Sample IMAP4rev1 connection
3515 The following is a transcript of an IMAP4rev1 connection. A long
3516 line in this sample is broken for editorial clarity.
3518 S: * OK IMAP4rev1 Service Ready
3519 C: a001 login mrc secret
3520 S: a001 OK LOGIN completed
3521 C: a002 select inbox
3523 S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
3525 S: * OK [UNSEEN 17] Message 17 is the first unseen message
3526 S: * OK [UIDVALIDITY 3857529045] UIDs valid
3530 Crispin Standards Track [Page 63]
3532 RFC 2060 IMAP4rev1 December 1996
3535 S: a002 OK [READ-WRITE] SELECT completed
3536 C: a003 fetch 12 full
3537 S: * 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))
3548 S: a003 OK FETCH completed
3549 C: a004 fetch 12 body[header]
3550 S: * 12 FETCH (BODY[HEADER] {350}
3551 S: Date: Wed, 17 Jul 1996 02:23:25 -0700 (PDT)
3552 S: From: Terry Gray <gray@cac.washington.edu>
3553 S: Subject: IMAP4rev1 WG mtg summary and minutes
3554 S: To: imap@cac.washington.edu
3555 S: cc: minutes@CNRI.Reston.VA.US, John Klensin <KLENSIN@INFOODS.MIT.EDU>
3556 S: Message-Id: <B27397-0100000@cac.washington.edu>
3557 S: MIME-Version: 1.0
3558 S: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
3561 S: a004 OK FETCH completed
3562 C: a005 store 12 +flags \deleted
3563 S: * 12 FETCH (FLAGS (\Seen \Deleted))
3564 S: a005 OK +FLAGS completed
3566 S: * BYE IMAP4rev1 server terminating connection
3567 S: a006 OK LOGOUT completed
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.
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.
3586 Crispin Standards Track [Page 64]
3588 RFC 2060 IMAP4rev1 December 1996
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.
3596 address ::= "(" addr_name SPACE addr_adl SPACE addr_mailbox
3599 addr_adl ::= nstring
3600 ;; Holds route from [RFC-822] route-addr if
3603 addr_host ::= nstring
3604 ;; NIL indicates [RFC-822] group syntax.
3605 ;; Otherwise, holds [RFC-822] domain name
3607 addr_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
3613 addr_name ::= nstring
3614 ;; Holds phrase from [RFC-822] mailbox if
3617 alpha ::= "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" /
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" /
3627 append ::= "APPEND" SPACE mailbox [SPACE flag_list]
3628 [SPACE date_time] SPACE literal
3630 astring ::= atom / string
3632 atom ::= 1*ATOM_CHAR
3634 ATOM_CHAR ::= <any CHAR except atom_specials>
3636 atom_specials ::= "(" / ")" / "{" / SPACE / CTL / list_wildcards /
3642 Crispin Standards Track [Page 65]
3644 RFC 2060 IMAP4rev1 December 1996
3647 authenticate ::= "AUTHENTICATE" SPACE auth_type *(CRLF base64)
3650 ;; Defined by [IMAP-AUTH]
3652 base64 ::= *(4base64_char) [base64_terminal]
3654 base64_char ::= alpha / digit / "+" / "/"
3656 base64_terminal ::= (2base64_char "==") / (3base64_char "=")
3658 body ::= "(" body_type_1part / body_type_mpart ")"
3660 body_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.
3668 body_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
3674 body_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
3680 body_fields ::= body_fld_param SPACE body_fld_id SPACE
3681 body_fld_desc SPACE body_fld_enc SPACE
3684 body_fld_desc ::= nstring
3686 body_fld_dsp ::= "(" string SPACE body_fld_param ")" / nil
3688 body_fld_enc ::= (<"> ("7BIT" / "8BIT" / "BINARY" / "BASE64"/
3689 "QUOTED-PRINTABLE") <">) / string
3691 body_fld_id ::= nstring
3693 body_fld_lang ::= nstring / "(" 1#string ")"
3698 Crispin Standards Track [Page 66]
3700 RFC 2060 IMAP4rev1 December 1996
3703 body_fld_lines ::= number
3705 body_fld_md5 ::= nstring
3707 body_fld_octets ::= number
3709 body_fld_param ::= "(" 1#(string SPACE string) ")" / nil
3711 body_type_1part ::= (body_type_basic / body_type_msg / body_type_text)
3712 [SPACE body_ext_1part]
3714 body_type_basic ::= media_basic SPACE body_fields
3715 ;; MESSAGE subtype MUST NOT be "RFC822"
3717 body_type_mpart ::= 1*body SPACE media_subtype
3718 [SPACE body_ext_mpart]
3720 body_type_msg ::= media_message SPACE body_fields SPACE envelope
3721 SPACE body SPACE body_fld_lines
3723 body_type_text ::= media_text SPACE body_fields SPACE body_fld_lines
3725 capability ::= "AUTH=" auth_type / atom
3726 ;; New capabilities MUST begin with "X" or be
3727 ;; registered with IANA as standard or
3730 capability_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
3736 CHAR ::= <any 7-bit US-ASCII character except NUL,
3739 CHAR8 ::= <any 8-bit octet except NUL, 0x01 - 0xff>
3741 command ::= tag SPACE (command_any / command_auth /
3742 command_nonauth / command_select) CRLF
3743 ;; Modal based on state
3745 command_any ::= "CAPABILITY" / "LOGOUT" / "NOOP" / x_command
3746 ;; Valid in all states
3748 command_auth ::= append / create / delete / examine / list / lsub /
3749 rename / select / status / subscribe / unsubscribe
3750 ;; Valid only in Authenticated or Selected state
3754 Crispin Standards Track [Page 67]
3756 RFC 2060 IMAP4rev1 December 1996
3759 command_nonauth ::= login / authenticate
3760 ;; Valid only when in Non-Authenticated state
3762 command_select ::= "CHECK" / "CLOSE" / "EXPUNGE" /
3763 copy / fetch / store / uid / search
3764 ;; Valid only when in Selected state
3766 continue_req ::= "+" SPACE (resp_text / base64)
3768 copy ::= "COPY" SPACE set SPACE mailbox
3770 CR ::= <ASCII CR, carriage return, 0x0D>
3772 create ::= "CREATE" SPACE mailbox
3773 ;; Use of INBOX gives a NO error
3777 CTL ::= <any ASCII control character and DEL,
3780 date ::= date_text / <"> date_text <">
3782 date_day ::= 1*2digit
3785 date_day_fixed ::= (SPACE digit) / 2digit
3786 ;; Fixed-format version of date_day
3788 date_month ::= "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" /
3789 "Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec"
3791 date_text ::= date_day "-" date_month "-" date_year
3793 date_year ::= 4digit
3795 date_time ::= <"> date_day_fixed "-" date_month "-" date_year
3796 SPACE time SPACE zone <">
3798 delete ::= "DELETE" SPACE mailbox
3799 ;; Use of INBOX gives a NO error
3801 digit ::= "0" / digit_nz
3803 digit_nz ::= "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" /
3810 Crispin Standards Track [Page 68]
3812 RFC 2060 IMAP4rev1 December 1996
3815 envelope ::= "(" 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 ")"
3820 env_bcc ::= "(" 1*address ")" / nil
3822 env_cc ::= "(" 1*address ")" / nil
3824 env_date ::= nstring
3826 env_from ::= "(" 1*address ")" / nil
3828 env_in_reply_to ::= nstring
3830 env_message_id ::= nstring
3832 env_reply_to ::= "(" 1*address ")" / nil
3834 env_sender ::= "(" 1*address ")" / nil
3836 env_subject ::= nstring
3838 env_to ::= "(" 1*address ")" / nil
3840 examine ::= "EXAMINE" SPACE mailbox
3842 fetch ::= "FETCH" SPACE set SPACE ("ALL" / "FULL" /
3843 "FAST" / fetch_att / "(" 1#fetch_att ")")
3845 fetch_att ::= "ENVELOPE" / "FLAGS" / "INTERNALDATE" /
3846 "RFC822" [".HEADER" / ".SIZE" / ".TEXT"] /
3847 "BODY" ["STRUCTURE"] / "UID" /
3848 "BODY" [".PEEK"] section
3849 ["<" number "." nz_number ">"]
3851 flag ::= "\Answered" / "\Flagged" / "\Deleted" /
3852 "\Seen" / "\Draft" / flag_keyword / flag_extension
3854 flag_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.
3862 flag_keyword ::= atom
3866 Crispin Standards Track [Page 69]
3868 RFC 2060 IMAP4rev1 December 1996
3871 flag_list ::= "(" #flag ")"
3873 greeting ::= "*" SPACE (resp_cond_auth / resp_cond_bye) CRLF
3875 header_fld_name ::= astring
3877 header_list ::= "(" 1#header_fld_name ")"
3879 LF ::= <ASCII LF, line feed, 0x0A>
3881 list ::= "LIST" SPACE mailbox SPACE list_mailbox
3883 list_mailbox ::= 1*(ATOM_CHAR / list_wildcards) / string
3885 list_wildcards ::= "%" / "*"
3887 literal ::= "{" number "}" CRLF *CHAR8
3888 ;; Number represents the number of CHAR8 octets
3890 login ::= "LOGIN" SPACE userid SPACE password
3892 lsub ::= "LSUB" SPACE mailbox SPACE list_mailbox
3894 mailbox ::= "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.
3900 mailbox_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"
3909 mailbox_list ::= "(" #("\Marked" / "\Noinferiors" /
3910 "\Noselect" / "\Unmarked" / flag_extension) ")"
3911 SPACE (<"> QUOTED_CHAR <"> / nil) SPACE mailbox
3913 media_basic ::= (<"> ("APPLICATION" / "AUDIO" / "IMAGE" /
3914 "MESSAGE" / "VIDEO") <">) / string)
3916 ;; Defined in [MIME-IMT]
3918 media_message ::= <"> "MESSAGE" <"> SPACE <"> "RFC822" <">
3922 Crispin Standards Track [Page 70]
3924 RFC 2060 IMAP4rev1 December 1996
3927 ;; Defined in [MIME-IMT]
3929 media_subtype ::= string
3930 ;; Defined in [MIME-IMT]
3932 media_text ::= <"> "TEXT" <"> SPACE media_subtype
3933 ;; Defined in [MIME-IMT]
3935 message_data ::= nz_number SPACE ("EXPUNGE" /
3936 ("FETCH" SPACE msg_att))
3938 msg_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) ")"
3949 nstring ::= string / nil
3952 ;; Unsigned 32-bit integer
3953 ;; (0 <= n < 4,294,967,296)
3955 nz_number ::= digit_nz *digit
3956 ;; Non-zero unsigned 32-bit integer
3957 ;; (0 < n < 4,294,967,296)
3959 password ::= astring
3961 quoted ::= <"> *QUOTED_CHAR <">
3963 QUOTED_CHAR ::= <any TEXT_CHAR except quoted_specials> /
3966 quoted_specials ::= <"> / "\"
3968 rename ::= "RENAME" SPACE mailbox SPACE mailbox
3969 ;; Use of INBOX as a destination gives a NO error
3971 response ::= *(continue_req / response_data) response_done
3973 response_data ::= "*" SPACE (resp_cond_state / resp_cond_bye /
3974 mailbox_data / message_data / capability_data)
3978 Crispin Standards Track [Page 71]
3980 RFC 2060 IMAP4rev1 December 1996
3985 response_done ::= response_tagged / response_fatal
3987 response_fatal ::= "*" SPACE resp_cond_bye CRLF
3988 ;; Server closes connection immediately
3990 response_tagged ::= tag SPACE resp_cond_state CRLF
3992 resp_cond_auth ::= ("OK" / "PREAUTH") SPACE resp_text
3993 ;; Authentication condition
3995 resp_cond_bye ::= "BYE" SPACE resp_text
3997 resp_cond_state ::= ("OK" / "NO" / "BAD") SPACE resp_text
4000 resp_text ::= ["[" resp_text_code "]" SPACE] (text_mime2 / text)
4001 ;; text SHOULD NOT begin with "[" or "="
4003 resp_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 "]">]
4010 search ::= "SEARCH" SPACE ["CHARSET" SPACE astring SPACE]
4012 ;; [CHARSET] MUST be registered with IANA
4014 search_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]
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 /
4034 Crispin Standards Track [Page 72]
4036 RFC 2060 IMAP4rev1 December 1996
4039 "UID" SPACE set / "UNDRAFT" / set /
4040 "(" 1#search_key ")"
4042 section ::= "[" [section_text / (nz_number *["." nz_number]
4043 ["." (section_text / "MIME")])] "]"
4045 section_text ::= "HEADER" / "HEADER.FIELDS" [".NOT"]
4046 SPACE header_list / "TEXT"
4048 select ::= "SELECT" SPACE mailbox
4050 sequence_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
4057 set ::= sequence_num / (sequence_num ":" sequence_num) /
4059 ;; Identifies a set of messages. For message
4060 ;; sequence numbers, these are consecutive
4061 ;; numbers from 1 to the number of messages in
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.
4068 SPACE ::= <ASCII SP, space, 0x20>
4070 status ::= "STATUS" SPACE mailbox SPACE "(" 1#status_att ")"
4072 status_att ::= "MESSAGES" / "RECENT" / "UIDNEXT" / "UIDVALIDITY" /
4075 store ::= "STORE" SPACE set SPACE store_att_flags
4077 store_att_flags ::= (["+" / "-"] "FLAGS" [".SILENT"]) SPACE
4080 string ::= quoted / literal
4082 subscribe ::= "SUBSCRIBE" SPACE mailbox
4084 tag ::= 1*<any ATOM_CHAR except "+">
4086 text ::= 1*TEXT_CHAR
4090 Crispin Standards Track [Page 73]
4092 RFC 2060 IMAP4rev1 December 1996
4095 text_mime2 ::= "=?" <charset> "?" <encoding> "?"
4097 ;; Syntax defined in [MIME-HDRS]
4099 TEXT_CHAR ::= <any CHAR except CR and LF>
4101 time ::= 2digit ":" 2digit ":" 2digit
4102 ;; Hours minutes seconds
4104 uid ::= "UID" SPACE (copy / fetch / search / store)
4105 ;; Unique identifiers used instead of message
4108 uniqueid ::= nz_number
4109 ;; Strictly ascending
4111 unsubscribe ::= "UNSUBSCRIBE" SPACE mailbox
4115 x_command ::= "X" atom <experimental command arguments>
4117 zone ::= ("+" / "-") 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".
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.
4131 11. Security Considerations
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.
4137 A server error message for an AUTHENTICATE command which fails due to
4138 invalid credentials SHOULD NOT detail why the credentials are
4141 Use of the LOGIN command sends passwords in the clear. This can be
4142 avoided by using the AUTHENTICATE command instead.
4146 Crispin Standards Track [Page 74]
4148 RFC 2060 IMAP4rev1 December 1996
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.
4154 Additional security considerations are discussed in the section
4155 discussing the AUTHENTICATE and LOGIN commands.
4157 12. Author's Address
4160 Networks and Distributed Computing
4161 University of Washington
4162 4545 15th Aveneue NE
4163 Seattle, WA 98105-4527
4165 Phone: (206) 543-5762
4167 EMail: MRC@CAC.Washington.EDU
4202 Crispin Standards Track [Page 75]
4204 RFC 2060 IMAP4rev1 December 1996
4211 [ACAP] Myers, J. "ACAP -- Application Configuration Access Protocol",
4214 [CHARSET] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2,
4215 RFC 1700, USC/Information Sciences Institute, October 1994.
4217 [DISPOSITION] Troost, R., and Dorner, S., "Communicating Presentation
4218 Information in Internet Messages: The Content-Disposition Header",
4219 RFC 1806, June 1995.
4221 [IMAP-AUTH] Myers, J., "IMAP4 Authentication Mechanism", RFC 1731.
4222 Carnegie-Mellon University, December 1994.
4224 [IMAP-COMPAT] Crispin, M., "IMAP4 Compatibility with IMAP2bis", RFC
4225 2061, University of Washington, November 1996.
4227 [IMAP-DISC] Austein, R., "Synchronization Operations for Disconnected
4228 IMAP4 Clients", Work in Progress.
4230 [IMAP-HISTORICAL] Crispin, M. "IMAP4 Compatibility with IMAP2 and
4231 IMAP2bis", RFC 1732, University of Washington, December 1994.
4233 [IMAP-MODEL] Crispin, M., "Distributed Electronic Mail Models in
4234 IMAP4", RFC 1733, University of Washington, December 1994.
4236 [IMAP-OBSOLETE] Crispin, M., "Internet Message Access Protocol -
4237 Obsolete Syntax", RFC 2062, University of Washington, November 1996.
4239 [IMAP2] Crispin, M., "Interactive Mail Access Protocol - Version 2",
4240 RFC 1176, University of Washington, August 1990.
4242 [LANGUAGE-TAGS] Alvestrand, H., "Tags for the Identification of
4243 Languages", RFC 1766, March 1995.
4245 [MD5] Myers, J., and M. Rose, "The Content-MD5 Header Field", RFC
4248 [MIME-IMB] Freed, N., and N. Borenstein, "MIME (Multipurpose Internet
4249 Mail Extensions) Part One: Format of Internet Message Bodies", RFC
4250 2045, November 1996.
4252 [MIME-IMT] Freed, N., and N. Borenstein, "MIME (Multipurpose
4253 Internet Mail Extensions) Part Two: Media Types", RFC 2046,
4258 Crispin Standards Track [Page 76]
4260 RFC 2060 IMAP4rev1 December 1996
4263 [MIME-HDRS] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
4264 Part Three: Message Header Extensions for Non-ASCII Text", RFC
4265 2047, November 1996.
4267 [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text
4268 Messages", STD 11, RFC 822, University of Delaware, August 1982.
4270 [SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10,
4271 RFC 821, USC/Information Sciences Institute, August 1982.
4273 [UTF-7] Goldsmith, D., and Davis, M., "UTF-7: A Mail-Safe
4274 Transformation Format of Unicode", RFC 1642, July 1994.
4276 B. Changes from RFC 1730
4278 1) The STATUS command has been added.
4280 2) Clarify in the formal syntax that the "#" construct can never
4281 refer to multiple spaces.
4283 3) Obsolete syntax has been moved to a separate document.
4285 4) The PARTIAL command has been obsoleted.
4287 5) The RFC822.HEADER.LINES, RFC822.HEADER.LINES.NOT, RFC822.PEEK, and
4288 RFC822.TEXT.PEEK fetch attributes have been obsoleted.
4290 6) The "<" origin "." size ">" suffix for BODY text attributes has
4293 7) The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, MIME, and TEXT part
4294 specifiers have been added.
4296 8) Support for Content-Disposition and Content-Language has been
4299 9) The restriction on fetching nested MULTIPART parts has been
4302 10) Body part number 0 has been obsoleted.
4304 11) Server-supported authenticators are now identified by
4314 Crispin Standards Track [Page 77]
4316 RFC 2060 IMAP4rev1 December 1996
4319 12) The capability that identifies this protocol is now called
4320 "IMAP4rev1". A server that provides backwards support for RFC 1730
4321 SHOULD emit the "IMAP4" capability in addition to "IMAP4rev1" in its
4322 CAPABILITY response. Because RFC-1730 required "IMAP4" to appear as
4323 the first capability, it MUST listed first in the response.
4325 13) A description of the mailbox name namespace convention has been
4328 14) A description of the international mailbox name convention has
4331 15) The UID-NEXT and UID-VALIDITY status items are now called UIDNEXT
4332 and UIDVALIDITY. This is a change from the IMAP STATUS
4333 Work in Progress and not from RFC-1730
4335 16) Add a clarification that a null mailbox name argument to the LIST
4336 command returns an untagged LIST response with the hierarchy
4337 delimiter and root of the reference argument.
4339 17) Define terms such as "MUST", "SHOULD", and "MUST NOT".
4341 18) Add a section which defines message attributes and more
4342 thoroughly details the semantics of message sequence numbers, UIDs,
4345 19) Add a clarification detailing the circumstances when a client may
4346 send multiple commands without waiting for a response, and the
4347 circumstances in which ambiguities may result.
4349 20) Add a recommendation on server behavior for DELETE and RENAME
4350 when inferior hierarchical names of the given name exist.
4352 21) Add a clarification that a mailbox name may not be unilaterally
4353 unsubscribed by the server, even if that mailbox name no longer
4356 22) Add a clarification that LIST should return its results quickly
4357 without undue delay.
4359 23) Add a clarification that the date_time argument to APPEND sets
4360 the internal date of the message.
4362 24) Add a clarification on APPEND behavior when the target mailbox is
4363 the currently selected mailbox.
4370 Crispin Standards Track [Page 78]
4372 RFC 2060 IMAP4rev1 December 1996
4375 25) Add a clarification that external changes to flags should be
4376 always announced via an untagged FETCH even if the current command is
4377 a STORE with the ".SILENT" suffix.
4379 26) Add a clarification that COPY appends to the target mailbox.
4381 27) Add the NEWNAME response code.
4383 28) Rewrite the description of the untagged BYE response to clarify
4386 29) Change the reference for the body MD5 to refer to the proper RFC.
4388 30) Clarify that the formal syntax contains rules which may overlap,
4389 and that in the event of such an overlap the rule which occurs first
4392 31) Correct the definition of body_fld_param.
4394 32) More formal syntax for capability_data.
4396 33) Clarify that any case variant of "INBOX" must be interpreted as
4399 34) Clarify that the human-readable text in resp_text should not
4400 begin with "[" or "=".
4402 35) Change MIME references to Draft Standard documents.
4404 36) Clarify \Recent semantics.
4406 37) Additional examples.
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
4426 Crispin Standards Track [Page 79]
4428 RFC 2060 IMAP4rev1 December 1996
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
4482 Crispin Standards Track [Page 80]
4484 RFC 2060 IMAP4rev1 December 1996
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
4538 Crispin Standards Track [Page 81]
4540 RFC 2060 IMAP4rev1 December 1996
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
4594 Crispin Standards Track [Page 82]
projects / claws.git / blob