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diff --git a/vendor/github.com/mattermost/rsc/imap/rfc3501.txt b/vendor/github.com/mattermost/rsc/imap/rfc3501.txt new file mode 100644 index 000000000..5ab48e17c --- /dev/null +++ b/vendor/github.com/mattermost/rsc/imap/rfc3501.txt @@ -0,0 +1,6051 @@ + + + + + + +Network Working Group M. Crispin +Request for Comments: 3501 University of Washington +Obsoletes: 2060 March 2003 +Category: Standards Track + + + INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1 + +Status of this Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2003). All Rights Reserved. + +Abstract + + The Internet Message Access Protocol, Version 4rev1 (IMAP4rev1) + allows a client to access and manipulate electronic mail messages on + a server. IMAP4rev1 permits manipulation of mailboxes (remote + message folders) in a way that is functionally equivalent to local + folders. IMAP4rev1 also provides the capability for an offline + client to resynchronize with the server. + + IMAP4rev1 includes operations for creating, deleting, and renaming + mailboxes, checking for new messages, permanently removing messages, + setting and clearing flags, RFC 2822 and RFC 2045 parsing, searching, + and selective fetching of message attributes, texts, and portions + thereof. Messages in IMAP4rev1 are accessed by the use of numbers. + These numbers are either message sequence numbers or unique + identifiers. + + IMAP4rev1 supports a single server. A mechanism for accessing + configuration information to support multiple IMAP4rev1 servers is + discussed in RFC 2244. + + IMAP4rev1 does not specify a means of posting mail; this function is + handled by a mail transfer protocol such as RFC 2821. + + + + + + + + +Crispin Standards Track [Page 1] + +RFC 3501 IMAPv4 March 2003 + + +Table of Contents + + IMAP4rev1 Protocol Specification ................................ 4 + 1. How to Read This Document ............................... 4 + 1.1. Organization of This Document ........................... 4 + 1.2. Conventions Used in This Document ....................... 4 + 1.3. Special Notes to Implementors ........................... 5 + 2. Protocol Overview ....................................... 6 + 2.1. Link Level .............................................. 6 + 2.2. Commands and Responses .................................. 6 + 2.2.1. Client Protocol Sender and Server Protocol Receiver ..... 6 + 2.2.2. Server Protocol Sender and Client Protocol Receiver ..... 7 + 2.3. Message Attributes ...................................... 8 + 2.3.1. Message Numbers ......................................... 8 + 2.3.1.1. Unique Identifier (UID) Message Attribute ....... 8 + 2.3.1.2. Message Sequence Number Message Attribute ....... 10 + 2.3.2. Flags Message Attribute ................................. 11 + 2.3.3. Internal Date Message Attribute ......................... 12 + 2.3.4. [RFC-2822] Size Message Attribute ....................... 12 + 2.3.5. Envelope Structure Message Attribute .................... 12 + 2.3.6. Body Structure Message Attribute ........................ 12 + 2.4. Message Texts ........................................... 13 + 3. State and Flow Diagram .................................. 13 + 3.1. Not Authenticated State ................................. 13 + 3.2. Authenticated State ..................................... 13 + 3.3. Selected State .......................................... 13 + 3.4. Logout State ............................................ 14 + 4. Data Formats ............................................ 16 + 4.1. Atom .................................................... 16 + 4.2. Number .................................................. 16 + 4.3. String .................................................. 16 + 4.3.1. 8-bit and Binary Strings ................................ 17 + 4.4. Parenthesized List ...................................... 17 + 4.5. NIL ..................................................... 17 + 5. Operational Considerations .............................. 18 + 5.1. Mailbox Naming .......................................... 18 + 5.1.1. Mailbox Hierarchy Naming ................................ 19 + 5.1.2. Mailbox Namespace Naming Convention ..................... 19 + 5.1.3. Mailbox International Naming Convention ................. 19 + 5.2. Mailbox Size and Message Status Updates ................. 21 + 5.3. Response when no Command in Progress .................... 21 + 5.4. Autologout Timer ........................................ 22 + 5.5. Multiple Commands in Progress ........................... 22 + 6. Client Commands ........................................ 23 + 6.1. Client Commands - Any State ............................ 24 + 6.1.1. CAPABILITY Command ..................................... 24 + 6.1.2. NOOP Command ........................................... 25 + 6.1.3. LOGOUT Command ......................................... 26 + + + +Crispin Standards Track [Page 2] + +RFC 3501 IMAPv4 March 2003 + + + 6.2. Client Commands - Not Authenticated State .............. 26 + 6.2.1. STARTTLS Command ....................................... 27 + 6.2.2. AUTHENTICATE Command ................................... 28 + 6.2.3. LOGIN Command .......................................... 30 + 6.3. Client Commands - Authenticated State .................. 31 + 6.3.1. SELECT Command ......................................... 32 + 6.3.2. EXAMINE Command ........................................ 34 + 6.3.3. CREATE Command ......................................... 34 + 6.3.4. DELETE Command ......................................... 35 + 6.3.5. RENAME Command ......................................... 37 + 6.3.6. SUBSCRIBE Command ...................................... 39 + 6.3.7. UNSUBSCRIBE Command .................................... 39 + 6.3.8. LIST Command ........................................... 40 + 6.3.9. LSUB Command ........................................... 43 + 6.3.10. STATUS Command ......................................... 44 + 6.3.11. APPEND Command ......................................... 46 + 6.4. Client Commands - Selected State ....................... 47 + 6.4.1. CHECK Command .......................................... 47 + 6.4.2. CLOSE Command .......................................... 48 + 6.4.3. EXPUNGE Command ........................................ 49 + 6.4.4. SEARCH Command ......................................... 49 + 6.4.5. FETCH Command .......................................... 54 + 6.4.6. STORE Command .......................................... 58 + 6.4.7. COPY Command ........................................... 59 + 6.4.8. UID Command ............................................ 60 + 6.5. Client Commands - Experimental/Expansion ............... 62 + 6.5.1. X<atom> Command ........................................ 62 + 7. Server Responses ....................................... 62 + 7.1. Server Responses - Status Responses .................... 63 + 7.1.1. OK Response ............................................ 65 + 7.1.2. NO Response ............................................ 66 + 7.1.3. BAD Response ........................................... 66 + 7.1.4. PREAUTH Response ....................................... 67 + 7.1.5. BYE Response ........................................... 67 + 7.2. Server Responses - Server and Mailbox Status ........... 68 + 7.2.1. CAPABILITY Response .................................... 68 + 7.2.2. LIST Response .......................................... 69 + 7.2.3. LSUB Response .......................................... 70 + 7.2.4 STATUS Response ........................................ 70 + 7.2.5. SEARCH Response ........................................ 71 + 7.2.6. FLAGS Response ......................................... 71 + 7.3. Server Responses - Mailbox Size ........................ 71 + 7.3.1. EXISTS Response ........................................ 71 + 7.3.2. RECENT Response ........................................ 72 + 7.4. Server Responses - Message Status ...................... 72 + 7.4.1. EXPUNGE Response ....................................... 72 + 7.4.2. FETCH Response ......................................... 73 + 7.5. Server Responses - Command Continuation Request ........ 79 + + + +Crispin Standards Track [Page 3] + +RFC 3501 IMAPv4 March 2003 + + + 8. Sample IMAP4rev1 connection ............................ 80 + 9. Formal Syntax .......................................... 81 + 10. Author's Note .......................................... 92 + 11. Security Considerations ................................ 92 + 11.1. STARTTLS Security Considerations ....................... 92 + 11.2. Other Security Considerations .......................... 93 + 12. IANA Considerations .................................... 94 + Appendices ..................................................... 95 + A. References ............................................. 95 + B. Changes from RFC 2060 .................................. 97 + C. Key Word Index ......................................... 103 + Author's Address ............................................... 107 + Full Copyright Statement ....................................... 108 + +IMAP4rev1 Protocol Specification + +1. How to Read This Document + +1.1. Organization of This Document + + This document is written from the point of view of the implementor of + an IMAP4rev1 client or server. Beyond the protocol overview in + section 2, it is not optimized for someone trying to understand the + operation of the protocol. The material in sections 3 through 5 + provides the general context and definitions with which IMAP4rev1 + operates. + + Sections 6, 7, and 9 describe the IMAP commands, responses, and + syntax, respectively. The relationships among these are such that it + is almost impossible to understand any of them separately. In + particular, do not attempt to deduce command syntax from the command + section alone; instead refer to the Formal Syntax section. + +1.2. Conventions Used in This Document + + "Conventions" are basic principles or procedures. Document + conventions are noted in this section. + + In examples, "C:" and "S:" indicate lines sent by the client and + server respectively. + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "MAY", and "OPTIONAL" in this document are to + be interpreted as described in [KEYWORDS]. + + The word "can" (not "may") is used to refer to a possible + circumstance or situation, as opposed to an optional facility of the + protocol. + + + +Crispin Standards Track [Page 4] + +RFC 3501 IMAPv4 March 2003 + + + "User" is used to refer to a human user, whereas "client" refers to + the software being run by the user. + + "Connection" refers to the entire sequence of client/server + interaction from the initial establishment of the network connection + until its termination. + + "Session" refers to the sequence of client/server interaction from + the time that a mailbox is selected (SELECT or EXAMINE command) until + the time that selection ends (SELECT or EXAMINE of another mailbox, + CLOSE command, or connection termination). + + Characters are 7-bit US-ASCII unless otherwise specified. Other + character sets are indicated using a "CHARSET", as described in + [MIME-IMT] and defined in [CHARSET]. CHARSETs have important + additional semantics in addition to defining character set; refer to + these documents for more detail. + + There are several protocol conventions in IMAP. These refer to + aspects of the specification which are not strictly part of the IMAP + protocol, but reflect generally-accepted practice. Implementations + need to be aware of these conventions, and avoid conflicts whether or + not they implement the convention. For example, "&" may not be used + as a hierarchy delimiter since it conflicts with the Mailbox + International Naming Convention, and other uses of "&" in mailbox + names are impacted as well. + +1.3. Special Notes to Implementors + + Implementors of the IMAP protocol are strongly encouraged to read the + IMAP implementation recommendations document [IMAP-IMPLEMENTATION] in + conjunction with this document, to help understand the intricacies of + this protocol and how best to build an interoperable product. + + IMAP4rev1 is designed to be upwards compatible from the [IMAP2] and + unpublished IMAP2bis protocols. IMAP4rev1 is largely compatible with + the IMAP4 protocol described in RFC 1730; the exception being in + certain facilities added in RFC 1730 that proved problematic and were + subsequently removed. In the course of the evolution of IMAP4rev1, + some aspects in the earlier protocols have become obsolete. Obsolete + commands, responses, and data formats which an IMAP4rev1 + implementation can encounter when used with an earlier implementation + are described in [IMAP-OBSOLETE]. + + Other compatibility issues with IMAP2bis, the most common variant of + the earlier protocol, are discussed in [IMAP-COMPAT]. A full + discussion of compatibility issues with rare (and presumed extinct) + + + + +Crispin Standards Track [Page 5] + +RFC 3501 IMAPv4 March 2003 + + + variants of [IMAP2] is in [IMAP-HISTORICAL]; this document is + primarily of historical interest. + + IMAP was originally developed for the older [RFC-822] standard, and + as a consequence several fetch items in IMAP incorporate "RFC822" in + their name. With the exception of RFC822.SIZE, there are more modern + replacements; for example, the modern version of RFC822.HEADER is + BODY.PEEK[HEADER]. In all cases, "RFC822" should be interpreted as a + reference to the updated [RFC-2822] standard. + +2. Protocol Overview + +2.1. Link Level + + The IMAP4rev1 protocol assumes a reliable data stream such as that + provided by TCP. When TCP is used, an IMAP4rev1 server listens on + port 143. + +2.2. Commands and Responses + + An IMAP4rev1 connection consists of the establishment of a + client/server network connection, an initial greeting from the + server, and client/server interactions. These client/server + interactions consist of a client command, server data, and a server + completion result response. + + All interactions transmitted by client and server are in the form of + lines, that is, strings that end with a CRLF. The protocol receiver + of an IMAP4rev1 client or server is either reading a line, or is + reading a sequence of octets with a known count followed by a line. + +2.2.1. Client Protocol Sender and Server Protocol Receiver + + The client command begins an operation. Each client command is + prefixed with an identifier (typically a short alphanumeric string, + e.g., A0001, A0002, etc.) called a "tag". A different tag is + generated by the client for each command. + + Clients MUST follow the syntax outlined in this specification + strictly. It is a syntax error to send a command with missing or + extraneous spaces or arguments. + + There are two cases in which a line from the client does not + represent a complete command. In one case, a command argument is + quoted with an octet count (see the description of literal in String + under Data Formats); in the other case, the command arguments require + server feedback (see the AUTHENTICATE command). In either case, the + + + + +Crispin Standards Track [Page 6] + +RFC 3501 IMAPv4 March 2003 + + + server sends a command continuation request response if it is ready + for the octets (if appropriate) and the remainder of the command. + This response is prefixed with the token "+". + + Note: If instead, the server detected an error in the + command, it sends a BAD completion response with a tag + matching the command (as described below) to reject the + command and prevent the client from sending any more of the + command. + + It is also possible for the server to send a completion + response for some other command (if multiple commands are + in progress), or untagged data. In either case, the + command continuation request is still pending; the client + takes the appropriate action for the response, and reads + another response from the server. In all cases, the client + MUST send a complete command (including receiving all + command continuation request responses and command + continuations for the command) before initiating a new + command. + + The protocol receiver of an IMAP4rev1 server reads a command line + from the client, parses the command and its arguments, and transmits + server data and a server command completion result response. + +2.2.2. Server Protocol Sender and Client Protocol Receiver + + Data transmitted by the server to the client and status responses + that do not indicate command completion are prefixed with the token + "*", and are called untagged responses. + + Server data MAY be sent as a result of a client command, or MAY be + sent unilaterally by the server. There is no syntactic difference + between server data that resulted from a specific command and server + data that were sent unilaterally. + + The server completion result response indicates the success or + failure of the operation. It is tagged with the same tag as the + client command which began the operation. Thus, if more than one + command is in progress, the tag in a server completion response + identifies the command to which the response applies. There are + three possible server completion responses: OK (indicating success), + NO (indicating failure), or BAD (indicating a protocol error such as + unrecognized command or command syntax error). + + Servers SHOULD enforce the syntax outlined in this specification + strictly. Any client command with a protocol syntax error, including + (but not limited to) missing or extraneous spaces or arguments, + + + +Crispin Standards Track [Page 7] + +RFC 3501 IMAPv4 March 2003 + + + SHOULD be rejected, and the client given a BAD server completion + response. + + The protocol receiver of an IMAP4rev1 client reads a response line + from the server. It then takes action on the response based upon the + first token of the response, which can be a tag, a "*", or a "+". + + A client MUST be prepared to accept any server response at all times. + This includes server data that was not requested. Server data SHOULD + be recorded, so that the client can reference its recorded copy + rather than sending a command to the server to request the data. In + the case of certain server data, the data MUST be recorded. + + This topic is discussed in greater detail in the Server Responses + section. + +2.3. Message Attributes + + In addition to message text, each message has several attributes + associated with it. These attributes can be retrieved individually + or in conjunction with other attributes or message texts. + +2.3.1. Message Numbers + + Messages in IMAP4rev1 are accessed by one of two numbers; the unique + identifier or the message sequence number. + + +2.3.1.1. Unique Identifier (UID) Message Attribute + + A 32-bit value assigned to each message, which when used with the + unique identifier validity value (see below) forms a 64-bit value + that MUST NOT refer to any other message in the mailbox or any + subsequent mailbox with the same name forever. Unique identifiers + are assigned in a strictly ascending fashion in the mailbox; as each + message is added to the mailbox it is assigned a higher UID than the + message(s) which were added previously. Unlike message sequence + numbers, unique identifiers are not necessarily contiguous. + + The unique identifier of a message MUST NOT change during the + session, and SHOULD NOT change between sessions. Any change of + unique identifiers between sessions MUST be detectable using the + UIDVALIDITY mechanism discussed below. Persistent unique identifiers + are required for a client to resynchronize its state from a previous + session with the server (e.g., disconnected or offline access + clients); this is discussed further in [IMAP-DISC]. + + + + + +Crispin Standards Track [Page 8] + +RFC 3501 IMAPv4 March 2003 + + + Associated with every mailbox are two values which aid in unique + identifier handling: the next unique identifier value and the unique + identifier validity value. + + The next unique identifier value is the predicted value that will be + assigned to a new message in the mailbox. Unless the unique + identifier validity also changes (see below), the next unique + identifier value MUST have the following two characteristics. First, + the next unique identifier value MUST NOT change unless new messages + are added to the mailbox; and second, the next unique identifier + value MUST change whenever new messages are added to the mailbox, + even if those new messages are subsequently expunged. + + Note: The next unique identifier value is intended to + provide a means for a client to determine whether any + messages have been delivered to the mailbox since the + previous time it checked this value. It is not intended to + provide any guarantee that any message will have this + unique identifier. A client can only assume, at the time + that it obtains the next unique identifier value, that + messages arriving after that time will have a UID greater + than or equal to that value. + + The unique identifier validity value is sent in a UIDVALIDITY + response code in an OK untagged response at mailbox selection time. + If unique identifiers from an earlier session fail to persist in this + session, the unique identifier validity value MUST be greater than + the one used in the earlier session. + + Note: Ideally, unique identifiers SHOULD persist at all + times. Although this specification recognizes that failure + to persist can be unavoidable in certain server + environments, it STRONGLY ENCOURAGES message store + implementation techniques that avoid this problem. For + example: + + 1) Unique identifiers MUST be strictly ascending in the + mailbox at all times. If the physical message store is + re-ordered by a non-IMAP agent, this requires that the + unique identifiers in the mailbox be regenerated, since + the former unique identifiers are no longer strictly + ascending as a result of the re-ordering. + + 2) If the message store has no mechanism to store unique + identifiers, it must regenerate unique identifiers at + each session, and each session must have a unique + UIDVALIDITY value. + + + + +Crispin Standards Track [Page 9] + +RFC 3501 IMAPv4 March 2003 + + + 3) If the mailbox is deleted and a new mailbox with the + same name is created at a later date, the server must + either keep track of unique identifiers from the + previous instance of the mailbox, or it must assign a + new UIDVALIDITY value to the new instance of the + mailbox. A good UIDVALIDITY value to use in this case + is a 32-bit representation of the creation date/time of + the mailbox. It is alright to use a constant such as + 1, but only if it guaranteed that unique identifiers + will never be reused, even in the case of a mailbox + being deleted (or renamed) and a new mailbox by the + same name created at some future time. + + 4) The combination of mailbox name, UIDVALIDITY, and UID + must refer to a single immutable message on that server + forever. In particular, the internal date, [RFC-2822] + size, envelope, body structure, and message texts + (RFC822, RFC822.HEADER, RFC822.TEXT, and all BODY[...] + fetch data items) must never change. This does not + include message numbers, nor does it include attributes + that can be set by a STORE command (e.g., FLAGS). + + +2.3.1.2. Message Sequence Number Message Attribute + + A relative position from 1 to the number of messages in the mailbox. + This position MUST be ordered by ascending unique identifier. As + each new message is added, it is assigned a message sequence number + that is 1 higher than the number of messages in the mailbox before + that new message was added. + + Message sequence numbers can be reassigned during the session. For + example, when a message is permanently removed (expunged) from the + mailbox, the message sequence number for all subsequent messages is + decremented. The number of messages in the mailbox is also + decremented. Similarly, a new message can be assigned a message + sequence number that was once held by some other message prior to an + expunge. + + In addition to accessing messages by relative position in the + mailbox, message sequence numbers can be used in mathematical + calculations. For example, if an untagged "11 EXISTS" is received, + and previously an untagged "8 EXISTS" was received, three new + messages have arrived with message sequence numbers of 9, 10, and 11. + Another example, if message 287 in a 523 message mailbox has UID + 12345, there are exactly 286 messages which have lesser UIDs and 236 + messages which have greater UIDs. + + + + +Crispin Standards Track [Page 10] + +RFC 3501 IMAPv4 March 2003 + + +2.3.2. Flags Message Attribute + + A list of zero or more named tokens associated with the message. A + flag is set by its addition to this list, and is cleared by its + removal. There are two types of flags in IMAP4rev1. A flag of + either type can be permanent or session-only. + + A system flag is a flag name that is pre-defined in this + specification. All system flags begin with "\". Certain system + flags (\Deleted and \Seen) have special semantics described + elsewhere. The currently-defined system flags are: + + \Seen + Message has been read + + \Answered + Message has been answered + + \Flagged + Message is "flagged" for urgent/special attention + + \Deleted + Message is "deleted" for removal by later EXPUNGE + + \Draft + Message has not completed composition (marked as a draft). + + \Recent + Message is "recently" arrived in this mailbox. This session + is the first session to have been notified about this + message; if the session is read-write, subsequent sessions + will not see \Recent set for this message. This flag can not + be altered by the client. + + If it is not possible to determine whether or not this + session is the first session to be notified about a message, + then that message SHOULD be considered recent. + + If multiple connections have the same mailbox selected + simultaneously, it is undefined which of these connections + will see newly-arrived messages with \Recent set and which + will see it without \Recent set. + + A keyword is defined by the server implementation. Keywords do not + begin with "\". Servers MAY permit the client to define new keywords + in the mailbox (see the description of the PERMANENTFLAGS response + code for more information). + + + + +Crispin Standards Track [Page 11] + +RFC 3501 IMAPv4 March 2003 + + + A flag can be permanent or session-only on a per-flag basis. + Permanent flags are those which the client can add or remove from the + message flags permanently; that is, concurrent and subsequent + sessions will see any change in permanent flags. Changes to session + flags are valid only in that session. + + Note: The \Recent system flag is a special case of a + session flag. \Recent can not be used as an argument in a + STORE or APPEND command, and thus can not be changed at + all. + +2.3.3. Internal Date Message Attribute + + The internal date and time of the message on the server. This + is not the date and time in the [RFC-2822] header, but rather a + date and time which reflects when the message was received. In + the case of messages delivered via [SMTP], this SHOULD be the + date and time of final delivery of the message as defined by + [SMTP]. In the case of messages delivered by the IMAP4rev1 COPY + command, this SHOULD be the internal date and time of the source + message. In the case of messages delivered by the IMAP4rev1 + APPEND command, this SHOULD be the date and time as specified in + the APPEND command description. All other cases are + implementation defined. + +2.3.4. [RFC-2822] Size Message Attribute + + The number of octets in the message, as expressed in [RFC-2822] + format. + +2.3.5. Envelope Structure Message Attribute + + A parsed representation of the [RFC-2822] header of the message. + Note that the IMAP Envelope structure is not the same as an + [SMTP] envelope. + +2.3.6. Body Structure Message Attribute + + A parsed representation of the [MIME-IMB] body structure + information of the message. + + + + + + + + + + + +Crispin Standards Track [Page 12] + +RFC 3501 IMAPv4 March 2003 + + +2.4. Message Texts + + In addition to being able to fetch the full [RFC-2822] text of a + message, IMAP4rev1 permits the fetching of portions of the full + message text. Specifically, it is possible to fetch the + [RFC-2822] message header, [RFC-2822] message body, a [MIME-IMB] + body part, or a [MIME-IMB] header. + +3. State and Flow Diagram + + Once the connection between client and server is established, an + IMAP4rev1 connection is in one of four states. The initial + state is identified in the server greeting. Most commands are + only valid in certain states. It is a protocol error for the + client to attempt a command while the connection is in an + inappropriate state, and the server will respond with a BAD or + NO (depending upon server implementation) command completion + result. + +3.1. Not Authenticated State + + In the not authenticated state, the client MUST supply + authentication credentials before most commands will be + permitted. This state is entered when a connection starts + unless the connection has been pre-authenticated. + +3.2. Authenticated State + + In the authenticated state, the client is authenticated and MUST + select a mailbox to access before commands that affect messages + will be permitted. This state is entered when a + pre-authenticated connection starts, when acceptable + authentication credentials have been provided, after an error in + selecting a mailbox, or after a successful CLOSE command. + +3.3. Selected State + + In a selected state, a mailbox has been selected to access. + This state is entered when a mailbox has been successfully + selected. + + + + + + + + + + + +Crispin Standards Track [Page 13] + +RFC 3501 IMAPv4 March 2003 + + +3.4. Logout State + + In the logout state, the connection is being terminated. This + state can be entered as a result of a client request (via the + LOGOUT command) or by unilateral action on the part of either + the client or server. + + If the client requests the logout state, the server MUST send an + untagged BYE response and a tagged OK response to the LOGOUT + command before the server closes the connection; and the client + MUST read the tagged OK response to the LOGOUT command before + the client closes the connection. + + A server MUST NOT unilaterally close the connection without + sending an untagged BYE response that contains the reason for + having done so. A client SHOULD NOT unilaterally close the + connection, and instead SHOULD issue a LOGOUT command. If the + server detects that the client has unilaterally closed the + connection, the server MAY omit the untagged BYE response and + simply close its connection. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 14] + +RFC 3501 IMAPv4 March 2003 + + + +----------------------+ + |connection established| + +----------------------+ + || + \/ + +--------------------------------------+ + | server greeting | + +--------------------------------------+ + || (1) || (2) || (3) + \/ || || + +-----------------+ || || + |Not Authenticated| || || + +-----------------+ || || + || (7) || (4) || || + || \/ \/ || + || +----------------+ || + || | Authenticated |<=++ || + || +----------------+ || || + || || (7) || (5) || (6) || + || || \/ || || + || || +--------+ || || + || || |Selected|==++ || + || || +--------+ || + || || || (7) || + \/ \/ \/ \/ + +--------------------------------------+ + | Logout | + +--------------------------------------+ + || + \/ + +-------------------------------+ + |both sides close the connection| + +-------------------------------+ + + (1) connection without pre-authentication (OK greeting) + (2) pre-authenticated connection (PREAUTH greeting) + (3) rejected connection (BYE greeting) + (4) successful LOGIN or AUTHENTICATE command + (5) successful SELECT or EXAMINE command + (6) CLOSE command, or failed SELECT or EXAMINE command + (7) LOGOUT command, server shutdown, or connection closed + + + + + + + + + + +Crispin Standards Track [Page 15] + +RFC 3501 IMAPv4 March 2003 + + +4. Data Formats + + IMAP4rev1 uses textual commands and responses. Data in + IMAP4rev1 can be in one of several forms: atom, number, string, + parenthesized list, or NIL. Note that a particular data item + may take more than one form; for example, a data item defined as + using "astring" syntax may be either an atom or a string. + +4.1. Atom + + An atom consists of one or more non-special characters. + +4.2. Number + + A number consists of one or more digit characters, and + represents a numeric value. + +4.3. String + + A string is in one of two forms: either literal or quoted + string. The literal form is the general form of string. The + quoted string form is an alternative that avoids the overhead of + processing a literal at the cost of limitations of characters + which may be used. + + A literal is a sequence of zero or more octets (including CR and + LF), prefix-quoted with an octet count in the form of an open + brace ("{"), the number of octets, close brace ("}"), and CRLF. + In the case of literals transmitted from server to client, the + CRLF is immediately followed by the octet data. In the case of + literals transmitted from client to server, the client MUST wait + to receive a command continuation request (described later in + this document) before sending the octet data (and the remainder + of the command). + + A quoted string is a sequence of zero or more 7-bit characters, + excluding CR and LF, with double quote (<">) characters at each + end. + + The empty string is represented as either "" (a quoted string + with zero characters between double quotes) or as {0} followed + by CRLF (a literal with an octet count of 0). + + Note: Even if the octet count is 0, a client transmitting a + literal MUST wait to receive a command continuation request. + + + + + + +Crispin Standards Track [Page 16] + +RFC 3501 IMAPv4 March 2003 + + +4.3.1. 8-bit and Binary Strings + + 8-bit textual and binary mail is supported through the use of a + [MIME-IMB] content transfer encoding. IMAP4rev1 implementations MAY + transmit 8-bit or multi-octet characters in literals, but SHOULD do + so only when the [CHARSET] is identified. + + Although a BINARY body encoding is defined, unencoded binary strings + are not permitted. A "binary string" is any string with NUL + characters. Implementations MUST encode binary data into a textual + form, such as BASE64, before transmitting the data. A string with an + excessive amount of CTL characters MAY also be considered to be + binary. + +4.4. Parenthesized List + + Data structures are represented as a "parenthesized list"; a sequence + of data items, delimited by space, and bounded at each end by + parentheses. A parenthesized list can contain other parenthesized + lists, using multiple levels of parentheses to indicate nesting. + + The empty list is represented as () -- a parenthesized list with no + members. + +4.5. NIL + + The special form "NIL" represents the non-existence of a particular + data item that is represented as a string or parenthesized list, as + distinct from the empty string "" or the empty parenthesized list (). + + Note: NIL is never used for any data item which takes the + form of an atom. For example, a mailbox name of "NIL" is a + mailbox named NIL as opposed to a non-existent mailbox + name. This is because mailbox uses "astring" syntax which + is an atom or a string. Conversely, an addr-name of NIL is + a non-existent personal name, because addr-name uses + "nstring" syntax which is NIL or a string, but never an + atom. + + + + + + + + + + + + + +Crispin Standards Track [Page 17] + +RFC 3501 IMAPv4 March 2003 + + +5. Operational Considerations + + The following rules are listed here to ensure that all IMAP4rev1 + implementations interoperate properly. + +5.1. Mailbox Naming + + Mailbox names are 7-bit. Client implementations MUST NOT attempt to + create 8-bit mailbox names, and SHOULD interpret any 8-bit mailbox + names returned by LIST or LSUB as UTF-8. Server implementations + SHOULD prohibit the creation of 8-bit mailbox names, and SHOULD NOT + return 8-bit mailbox names in LIST or LSUB. See section 5.1.3 for + more information on how to represent non-ASCII mailbox names. + + Note: 8-bit mailbox names were undefined in earlier + versions of this protocol. Some sites used a local 8-bit + character set to represent non-ASCII mailbox names. Such + usage is not interoperable, and is now formally deprecated. + + The case-insensitive mailbox name INBOX is a special name reserved to + mean "the primary mailbox for this user on this server". The + interpretation of all other names is implementation-dependent. + + In particular, this specification takes no position on case + sensitivity in non-INBOX mailbox names. Some server implementations + are fully case-sensitive; others preserve case of a newly-created + name but otherwise are case-insensitive; and yet others coerce names + to a particular case. Client implementations MUST interact with any + of these. If a server implementation interprets non-INBOX mailbox + names as case-insensitive, it MUST treat names using the + international naming convention specially as described in section + 5.1.3. + + There are certain client considerations when creating a new mailbox + name: + + 1) Any character which is one of the atom-specials (see the Formal + Syntax) will require that the mailbox name be represented as a + quoted string or literal. + + 2) CTL and other non-graphic characters are difficult to represent + in a user interface and are best avoided. + + 3) Although the list-wildcard characters ("%" and "*") are valid + in a mailbox name, it is difficult to use such mailbox names + with the LIST and LSUB commands due to the conflict with + wildcard interpretation. + + + + +Crispin Standards Track [Page 18] + +RFC 3501 IMAPv4 March 2003 + + + 4) Usually, a character (determined by the server implementation) + is reserved to delimit levels of hierarchy. + + 5) Two characters, "#" and "&", have meanings by convention, and + should be avoided except when used in that convention. + +5.1.1. Mailbox Hierarchy Naming + + If it is desired to export hierarchical mailbox names, mailbox names + MUST be left-to-right hierarchical using a single character to + separate levels of hierarchy. The same hierarchy separator character + is used for all levels of hierarchy within a single name. + +5.1.2. Mailbox Namespace Naming Convention + + By convention, the first hierarchical element of any mailbox name + which begins with "#" identifies the "namespace" of the remainder of + the name. This makes it possible to disambiguate between different + types of mailbox stores, each of which have their own namespaces. + + For example, implementations which offer access to USENET + newsgroups MAY use the "#news" namespace to partition the + USENET newsgroup namespace from that of other mailboxes. + Thus, the comp.mail.misc newsgroup would have a mailbox + name of "#news.comp.mail.misc", and the name + "comp.mail.misc" can refer to a different object (e.g., a + user's private mailbox). + +5.1.3. Mailbox International Naming Convention + + By convention, international mailbox names in IMAP4rev1 are specified + using a modified version of the UTF-7 encoding described in [UTF-7]. + Modified UTF-7 may also be usable in servers that implement an + earlier version of this protocol. + + In modified UTF-7, printable US-ASCII characters, except for "&", + represent themselves; that is, characters with octet values 0x20-0x25 + and 0x27-0x7e. The character "&" (0x26) is represented by the + two-octet sequence "&-". + + All other characters (octet values 0x00-0x1f and 0x7f-0xff) are + represented in modified BASE64, with a further modification from + [UTF-7] that "," is used instead of "/". Modified BASE64 MUST NOT be + used to represent any printing US-ASCII character which can represent + itself. + + + + + + +Crispin Standards Track [Page 19] + +RFC 3501 IMAPv4 March 2003 + + + "&" is used to shift to modified BASE64 and "-" to shift back to + US-ASCII. There is no implicit shift from BASE64 to US-ASCII, and + null shifts ("-&" while in BASE64; note that "&-" while in US-ASCII + means "&") are not permitted. However, all names start in US-ASCII, + and MUST end in US-ASCII; that is, a name that ends with a non-ASCII + ISO-10646 character MUST end with a "-"). + + The purpose of these modifications is to correct the following + problems with UTF-7: + + 1) UTF-7 uses the "+" character for shifting; this conflicts with + the common use of "+" in mailbox names, in particular USENET + newsgroup names. + + 2) UTF-7's encoding is BASE64 which uses the "/" character; this + conflicts with the use of "/" as a popular hierarchy delimiter. + + 3) UTF-7 prohibits the unencoded usage of "\"; this conflicts with + the use of "\" as a popular hierarchy delimiter. + + 4) UTF-7 prohibits the unencoded usage of "~"; this conflicts with + the use of "~" in some servers as a home directory indicator. + + 5) UTF-7 permits multiple alternate forms to represent the same + string; in particular, printable US-ASCII characters can be + represented in encoded form. + + Although modified UTF-7 is a convention, it establishes certain + requirements on server handling of any mailbox name with an + embedded "&" character. In particular, server implementations + MUST preserve the exact form of the modified BASE64 portion of a + modified UTF-7 name and treat that text as case-sensitive, even if + names are otherwise case-insensitive or case-folded. + + Server implementations SHOULD verify that any mailbox name with an + embedded "&" character, used as an argument to CREATE, is: in the + correctly modified UTF-7 syntax, has no superfluous shifts, and + has no encoding in modified BASE64 of any printing US-ASCII + character which can represent itself. However, client + implementations MUST NOT depend upon the server doing this, and + SHOULD NOT attempt to create a mailbox name with an embedded "&" + character unless it complies with the modified UTF-7 syntax. + + Server implementations which export a mail store that does not + follow the modified UTF-7 convention MUST convert to modified + UTF-7 any mailbox name that contains either non-ASCII characters + or the "&" character. + + + + +Crispin Standards Track [Page 20] + +RFC 3501 IMAPv4 March 2003 + + + For example, here is a mailbox name which mixes English, + Chinese, and Japanese text: + ~peter/mail/&U,BTFw-/&ZeVnLIqe- + + For example, the string "&Jjo!" is not a valid mailbox + name because it does not contain a shift to US-ASCII + before the "!". The correct form is "&Jjo-!". The + string "&U,BTFw-&ZeVnLIqe-" is not permitted because it + contains a superfluous shift. The correct form is + "&U,BTF2XlZyyKng-". + +5.2. Mailbox Size and Message Status Updates + + At any time, a server can send data that the client did not request. + Sometimes, such behavior is REQUIRED. For example, agents other than + the server MAY add messages to the mailbox (e.g., new message + delivery), change the flags of the messages in the mailbox (e.g., + simultaneous access to the same mailbox by multiple agents), or even + remove messages from the mailbox. A server MUST send mailbox size + updates automatically if a mailbox size change is observed during the + processing of a command. A server SHOULD send message flag updates + automatically, without requiring the client to request such updates + explicitly. + + Special rules exist for server notification of a client about the + removal of messages to prevent synchronization errors; see the + description of the EXPUNGE response for more detail. In particular, + it is NOT permitted to send an EXISTS response that would reduce the + number of messages in the mailbox; only the EXPUNGE response can do + this. + + Regardless of what implementation decisions a client makes on + remembering data from the server, a client implementation MUST record + mailbox size updates. It MUST NOT assume that any command after the + initial mailbox selection will return the size of the mailbox. + +5.3. Response when no Command in Progress + + Server implementations are permitted to send an untagged response + (except for EXPUNGE) while there is no command in progress. Server + implementations that send such responses MUST deal with flow control + considerations. Specifically, they MUST either (1) verify that the + size of the data does not exceed the underlying transport's available + window size, or (2) use non-blocking writes. + + + + + + + +Crispin Standards Track [Page 21] + +RFC 3501 IMAPv4 March 2003 + + +5.4. Autologout Timer + + If a server has an inactivity autologout timer, the duration of that + timer MUST be at least 30 minutes. The receipt of ANY command from + the client during that interval SHOULD suffice to reset the + autologout timer. + +5.5. Multiple Commands in Progress + + The client MAY send another command without waiting for the + completion result response of a command, subject to ambiguity rules + (see below) and flow control constraints on the underlying data + stream. Similarly, a server MAY begin processing another command + before processing the current command to completion, subject to + ambiguity rules. However, any command continuation request responses + and command continuations MUST be negotiated before any subsequent + command is initiated. + + The exception is if an ambiguity would result because of a command + that would affect the results of other commands. Clients MUST NOT + send multiple commands without waiting if an ambiguity would result. + If the server detects a possible ambiguity, it MUST execute commands + to completion in the order given by the client. + + The most obvious example of ambiguity is when a command would affect + the results of another command, e.g., a FETCH of a message's flags + and a STORE of that same message's flags. + + A non-obvious ambiguity occurs with commands that permit an untagged + EXPUNGE response (commands other than FETCH, STORE, and SEARCH), + since an untagged EXPUNGE response can invalidate sequence numbers in + a subsequent command. This is not a problem for FETCH, STORE, or + SEARCH commands because servers are prohibited from sending EXPUNGE + responses while any of those commands are in progress. Therefore, if + the client sends any command other than FETCH, STORE, or SEARCH, it + MUST wait for the completion result response before sending a command + with message sequence numbers. + + Note: UID FETCH, UID STORE, and UID SEARCH are different + commands from FETCH, STORE, and SEARCH. If the client + sends a UID command, it must wait for a completion result + response before sending a command with message sequence + numbers. + + + + + + + + +Crispin Standards Track [Page 22] + +RFC 3501 IMAPv4 March 2003 + + + For example, the following non-waiting command sequences are invalid: + + FETCH + NOOP + STORE + STORE + COPY + FETCH + COPY + COPY + CHECK + FETCH + + The following are examples of valid non-waiting command sequences: + + FETCH + STORE + SEARCH + CHECK + STORE + COPY + EXPUNGE + + UID SEARCH + UID SEARCH may be valid or invalid as a non-waiting + command sequence, depending upon whether or not the second UID + SEARCH contains message sequence numbers. + +6. Client Commands + + IMAP4rev1 commands are described in this section. Commands are + organized by the state in which the command is permitted. Commands + which are permitted in multiple states are listed in the minimum + permitted state (for example, commands valid in authenticated and + selected state are listed in the authenticated state commands). + + Command arguments, identified by "Arguments:" in the command + descriptions below, are described by function, not by syntax. The + precise syntax of command arguments is described in the Formal Syntax + section. + + Some commands cause specific server responses to be returned; these + are identified by "Responses:" in the command descriptions below. + See the response descriptions in the Responses section for + information on these responses, and the Formal Syntax section for the + precise syntax of these responses. It is possible for server data to + be transmitted as a result of any command. Thus, commands that do + not specifically require server data specify "no specific responses + for this command" instead of "none". + + The "Result:" in the command description refers to the possible + tagged status responses to a command, and any special interpretation + of these status responses. + + The state of a connection is only changed by successful commands + which are documented as changing state. A rejected command (BAD + response) never changes the state of the connection or of the + selected mailbox. A failed command (NO response) generally does not + change the state of the connection or of the selected mailbox; the + exception being the SELECT and EXAMINE commands. + + + +Crispin Standards Track [Page 23] + +RFC 3501 IMAPv4 March 2003 + + +6.1. Client Commands - Any State + + The following commands are valid in any state: CAPABILITY, NOOP, and + LOGOUT. + +6.1.1. CAPABILITY Command + + Arguments: none + + Responses: REQUIRED untagged response: CAPABILITY + + Result: OK - capability completed + BAD - command unknown or arguments invalid + + The CAPABILITY command requests a listing of capabilities that the + server supports. The server MUST send a single untagged + CAPABILITY response with "IMAP4rev1" as one of the listed + capabilities before the (tagged) OK response. + + A capability name which begins with "AUTH=" indicates that the + server supports that particular authentication mechanism. All + such names are, by definition, part of this specification. For + example, the authorization capability for an experimental + "blurdybloop" authenticator would be "AUTH=XBLURDYBLOOP" and not + "XAUTH=BLURDYBLOOP" or "XAUTH=XBLURDYBLOOP". + + Other capability names refer to extensions, revisions, or + amendments to this specification. See the documentation of the + CAPABILITY response for additional information. No capabilities, + beyond the base IMAP4rev1 set defined in this specification, are + enabled without explicit client action to invoke the capability. + + Client and server implementations MUST implement the STARTTLS, + LOGINDISABLED, and AUTH=PLAIN (described in [IMAP-TLS]) + capabilities. See the Security Considerations section for + important information. + + See the section entitled "Client Commands - + Experimental/Expansion" for information about the form of site or + implementation-specific capabilities. + + + + + + + + + + + +Crispin Standards Track [Page 24] + +RFC 3501 IMAPv4 March 2003 + + + Example: C: abcd CAPABILITY + S: * CAPABILITY IMAP4rev1 STARTTLS AUTH=GSSAPI + LOGINDISABLED + S: abcd OK CAPABILITY completed + C: efgh STARTTLS + S: efgh OK STARTLS completed + <TLS negotiation, further commands are under [TLS] layer> + C: ijkl CAPABILITY + S: * CAPABILITY IMAP4rev1 AUTH=GSSAPI AUTH=PLAIN + S: ijkl OK CAPABILITY completed + + +6.1.2. NOOP Command + + Arguments: none + + Responses: no specific responses for this command (but see below) + + Result: OK - noop completed + BAD - command unknown or arguments invalid + + The NOOP command always succeeds. It does nothing. + + Since any command can return a status update as untagged data, the + NOOP command can be used as a periodic poll for new messages or + message status updates during a period of inactivity (this is the + preferred method to do this). The NOOP command can also be used + to reset any inactivity autologout timer on the server. + + Example: C: a002 NOOP + S: a002 OK NOOP completed + . . . + C: a047 NOOP + S: * 22 EXPUNGE + S: * 23 EXISTS + S: * 3 RECENT + S: * 14 FETCH (FLAGS (\Seen \Deleted)) + S: a047 OK NOOP completed + + + + + + + + + + + + + +Crispin Standards Track [Page 25] + +RFC 3501 IMAPv4 March 2003 + + +6.1.3. LOGOUT Command + + Arguments: none + + Responses: REQUIRED untagged response: BYE + + Result: OK - logout completed + BAD - command unknown or arguments invalid + + The LOGOUT command informs the server that the client is done with + the connection. The server MUST send a BYE untagged response + before the (tagged) OK response, and then close the network + connection. + + Example: C: A023 LOGOUT + S: * BYE IMAP4rev1 Server logging out + S: A023 OK LOGOUT completed + (Server and client then close the connection) + +6.2. Client Commands - Not Authenticated State + + In the not authenticated state, the AUTHENTICATE or LOGIN command + establishes authentication and enters the authenticated state. The + AUTHENTICATE command provides a general mechanism for a variety of + authentication techniques, privacy protection, and integrity + checking; whereas the LOGIN command uses a traditional user name and + plaintext password pair and has no means of establishing privacy + protection or integrity checking. + + The STARTTLS command is an alternate form of establishing session + privacy protection and integrity checking, but does not establish + authentication or enter the authenticated state. + + Server implementations MAY allow access to certain mailboxes without + establishing authentication. This can be done by means of the + ANONYMOUS [SASL] authenticator described in [ANONYMOUS]. An older + convention is a LOGIN command using the userid "anonymous"; in this + case, a password is required although the server may choose to accept + any password. The restrictions placed on anonymous users are + implementation-dependent. + + Once authenticated (including as anonymous), it is not possible to + re-enter not authenticated state. + + + + + + + + +Crispin Standards Track [Page 26] + +RFC 3501 IMAPv4 March 2003 + + + In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), + the following commands are valid in the not authenticated state: + STARTTLS, AUTHENTICATE and LOGIN. See the Security Considerations + section for important information about these commands. + +6.2.1. STARTTLS Command + + Arguments: none + + Responses: no specific response for this command + + Result: OK - starttls completed, begin TLS negotiation + BAD - command unknown or arguments invalid + + A [TLS] negotiation begins immediately after the CRLF at the end + of the tagged OK response from the server. Once a client issues a + STARTTLS command, it MUST NOT issue further commands until a + server response is seen and the [TLS] negotiation is complete. + + The server remains in the non-authenticated state, even if client + credentials are supplied during the [TLS] negotiation. This does + not preclude an authentication mechanism such as EXTERNAL (defined + in [SASL]) from using client identity determined by the [TLS] + negotiation. + + Once [TLS] has been started, the client MUST discard cached + information about server capabilities and SHOULD re-issue the + CAPABILITY command. This is necessary to protect against man-in- + the-middle attacks which alter the capabilities list prior to + STARTTLS. The server MAY advertise different capabilities after + STARTTLS. + + Example: C: a001 CAPABILITY + S: * CAPABILITY IMAP4rev1 STARTTLS LOGINDISABLED + S: a001 OK CAPABILITY completed + C: a002 STARTTLS + S: a002 OK Begin TLS negotiation now + <TLS negotiation, further commands are under [TLS] layer> + C: a003 CAPABILITY + S: * CAPABILITY IMAP4rev1 AUTH=PLAIN + S: a003 OK CAPABILITY completed + C: a004 LOGIN joe password + S: a004 OK LOGIN completed + + + + + + + + +Crispin Standards Track [Page 27] + +RFC 3501 IMAPv4 March 2003 + + +6.2.2. AUTHENTICATE Command + + Arguments: authentication mechanism name + + Responses: continuation data can be requested + + Result: OK - authenticate completed, now in authenticated state + NO - authenticate failure: unsupported authentication + mechanism, credentials rejected + BAD - command unknown or arguments invalid, + authentication exchange cancelled + + The AUTHENTICATE command indicates a [SASL] authentication + mechanism to the server. If the server supports the requested + authentication mechanism, it performs an authentication protocol + exchange to authenticate and identify the client. It MAY also + negotiate an OPTIONAL security layer for subsequent protocol + interactions. If the requested authentication mechanism is not + supported, the server SHOULD reject the AUTHENTICATE command by + sending a tagged NO response. + + The AUTHENTICATE command does not support the optional "initial + response" feature of [SASL]. Section 5.1 of [SASL] specifies how + to handle an authentication mechanism which uses an initial + response. + + The service name specified by this protocol's profile of [SASL] is + "imap". + + The authentication protocol exchange consists of a series of + server challenges and client responses that are specific to the + authentication mechanism. A server challenge consists of a + command continuation request response with the "+" token followed + by a BASE64 encoded string. The client response consists of a + single line consisting of a BASE64 encoded string. If the client + wishes to cancel an authentication exchange, it issues a line + consisting of a single "*". If the server receives such a + response, it MUST reject the AUTHENTICATE command by sending a + tagged BAD response. + + If a security layer is negotiated through the [SASL] + authentication exchange, it takes effect immediately following the + CRLF that concludes the authentication exchange for the client, + and the CRLF of the tagged OK response for the server. + + While client and server implementations MUST implement the + AUTHENTICATE command itself, it is not required to implement any + authentication mechanisms other than the PLAIN mechanism described + + + +Crispin Standards Track [Page 28] + +RFC 3501 IMAPv4 March 2003 + + + in [IMAP-TLS]. Also, an authentication mechanism is not required + to support any security layers. + + Note: a server implementation MUST implement a + configuration in which it does NOT permit any plaintext + password mechanisms, unless either the STARTTLS command + has been negotiated or some other mechanism that + protects the session from password snooping has been + provided. Server sites SHOULD NOT use any configuration + which permits a plaintext password mechanism without + such a protection mechanism against password snooping. + Client and server implementations SHOULD implement + additional [SASL] mechanisms that do not use plaintext + passwords, such the GSSAPI mechanism described in [SASL] + and/or the [DIGEST-MD5] mechanism. + + Servers and clients can support multiple authentication + mechanisms. The server SHOULD list its supported authentication + mechanisms in the response to the CAPABILITY command so that the + client knows which authentication mechanisms to use. + + A server MAY include a CAPABILITY response code in the tagged OK + response of a successful AUTHENTICATE command in order to send + capabilities automatically. It is unnecessary for a client to + send a separate CAPABILITY command if it recognizes these + automatic capabilities. This should only be done if a security + layer was not negotiated by the AUTHENTICATE command, because the + tagged OK response as part of an AUTHENTICATE command is not + protected by encryption/integrity checking. [SASL] requires the + client to re-issue a CAPABILITY command in this case. + + If an AUTHENTICATE command fails with a NO response, the client + MAY try another authentication mechanism by issuing another + AUTHENTICATE command. It MAY also attempt to authenticate by + using the LOGIN command (see section 6.2.3 for more detail). In + other words, the client MAY request authentication types in + decreasing order of preference, with the LOGIN command as a last + resort. + + The authorization identity passed from the client to the server + during the authentication exchange is interpreted by the server as + the user name whose privileges the client is requesting. + + + + + + + + + +Crispin Standards Track [Page 29] + +RFC 3501 IMAPv4 March 2003 + + + Example: S: * OK IMAP4rev1 Server + C: A001 AUTHENTICATE GSSAPI + S: + + C: YIIB+wYJKoZIhvcSAQICAQBuggHqMIIB5qADAgEFoQMCAQ6iBw + MFACAAAACjggEmYYIBIjCCAR6gAwIBBaESGxB1Lndhc2hpbmd0 + b24uZWR1oi0wK6ADAgEDoSQwIhsEaW1hcBsac2hpdmFtcy5jYW + Mud2FzaGluZ3Rvbi5lZHWjgdMwgdCgAwIBAaEDAgEDooHDBIHA + cS1GSa5b+fXnPZNmXB9SjL8Ollj2SKyb+3S0iXMljen/jNkpJX + AleKTz6BQPzj8duz8EtoOuNfKgweViyn/9B9bccy1uuAE2HI0y + C/PHXNNU9ZrBziJ8Lm0tTNc98kUpjXnHZhsMcz5Mx2GR6dGknb + I0iaGcRerMUsWOuBmKKKRmVMMdR9T3EZdpqsBd7jZCNMWotjhi + vd5zovQlFqQ2Wjc2+y46vKP/iXxWIuQJuDiisyXF0Y8+5GTpAL + pHDc1/pIGmMIGjoAMCAQGigZsEgZg2on5mSuxoDHEA1w9bcW9n + FdFxDKpdrQhVGVRDIzcCMCTzvUboqb5KjY1NJKJsfjRQiBYBdE + NKfzK+g5DlV8nrw81uOcP8NOQCLR5XkoMHC0Dr/80ziQzbNqhx + O6652Npft0LQwJvenwDI13YxpwOdMXzkWZN/XrEqOWp6GCgXTB + vCyLWLlWnbaUkZdEYbKHBPjd8t/1x5Yg== + S: + YGgGCSqGSIb3EgECAgIAb1kwV6ADAgEFoQMCAQ+iSzBJoAMC + AQGiQgRAtHTEuOP2BXb9sBYFR4SJlDZxmg39IxmRBOhXRKdDA0 + uHTCOT9Bq3OsUTXUlk0CsFLoa8j+gvGDlgHuqzWHPSQg== + C: + S: + YDMGCSqGSIb3EgECAgIBAAD/////6jcyG4GE3KkTzBeBiVHe + ceP2CWY0SR0fAQAgAAQEBAQ= + C: YDMGCSqGSIb3EgECAgIBAAD/////3LQBHXTpFfZgrejpLlLImP + wkhbfa2QteAQAgAG1yYwE= + S: A001 OK GSSAPI authentication successful + + Note: The line breaks within server challenges and client + responses are for editorial clarity and are not in real + authenticators. + + +6.2.3. LOGIN Command + + Arguments: user name + password + + Responses: no specific responses for this command + + Result: OK - login completed, now in authenticated state + NO - login failure: user name or password rejected + BAD - command unknown or arguments invalid + + The LOGIN command identifies the client to the server and carries + the plaintext password authenticating this user. + + + + + + +Crispin Standards Track [Page 30] + +RFC 3501 IMAPv4 March 2003 + + + A server MAY include a CAPABILITY response code in the tagged OK + response to a successful LOGIN command in order to send + capabilities automatically. It is unnecessary for a client to + send a separate CAPABILITY command if it recognizes these + automatic capabilities. + + Example: C: a001 LOGIN SMITH SESAME + S: a001 OK LOGIN completed + + Note: Use of the LOGIN command over an insecure network + (such as the Internet) is a security risk, because anyone + monitoring network traffic can obtain plaintext passwords. + The LOGIN command SHOULD NOT be used except as a last + resort, and it is recommended that client implementations + have a means to disable any automatic use of the LOGIN + command. + + Unless either the STARTTLS command has been negotiated or + some other mechanism that protects the session from + password snooping has been provided, a server + implementation MUST implement a configuration in which it + advertises the LOGINDISABLED capability and does NOT permit + the LOGIN command. Server sites SHOULD NOT use any + configuration which permits the LOGIN command without such + a protection mechanism against password snooping. A client + implementation MUST NOT send a LOGIN command if the + LOGINDISABLED capability is advertised. + +6.3. Client Commands - Authenticated State + + In the authenticated state, commands that manipulate mailboxes as + atomic entities are permitted. Of these commands, the SELECT and + EXAMINE commands will select a mailbox for access and enter the + selected state. + + In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), + the following commands are valid in the authenticated state: SELECT, + EXAMINE, CREATE, DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, LSUB, + STATUS, and APPEND. + + + + + + + + + + + + +Crispin Standards Track [Page 31] + +RFC 3501 IMAPv4 March 2003 + + +6.3.1. SELECT Command + + Arguments: mailbox name + + Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT + REQUIRED OK untagged responses: UNSEEN, PERMANENTFLAGS, + UIDNEXT, UIDVALIDITY + + Result: OK - select completed, now in selected state + NO - select failure, now in authenticated state: no + such mailbox, can't access mailbox + BAD - command unknown or arguments invalid + + The SELECT command selects a mailbox so that messages in the + mailbox can be accessed. Before returning an OK to the client, + the server MUST send the following untagged data to the client. + Note that earlier versions of this protocol only required the + FLAGS, EXISTS, and RECENT untagged data; consequently, client + implementations SHOULD implement default behavior for missing data + as discussed with the individual item. + + FLAGS Defined flags in the mailbox. See the description + of the FLAGS response for more detail. + + <n> EXISTS The number of messages in the mailbox. See the + description of the EXISTS response for more detail. + + <n> RECENT The number of messages with the \Recent flag set. + See the description of the RECENT response for more + detail. + + OK [UNSEEN <n>] + The message sequence number of the first unseen + message in the mailbox. If this is missing, the + client can not make any assumptions about the first + unseen message in the mailbox, and needs to issue a + SEARCH command if it wants to find it. + + OK [PERMANENTFLAGS (<list of flags>)] + A list of message flags that the client can change + permanently. If this is missing, the client should + assume that all flags can be changed permanently. + + OK [UIDNEXT <n>] + The next unique identifier value. Refer to section + 2.3.1.1 for more information. If this is missing, + the client can not make any assumptions about the + next unique identifier value. + + + +Crispin Standards Track [Page 32] + +RFC 3501 IMAPv4 March 2003 + + + OK [UIDVALIDITY <n>] + The unique identifier validity value. Refer to + section 2.3.1.1 for more information. If this is + missing, the server does not support unique + identifiers. + + Only one mailbox can be selected at a time in a connection; + simultaneous access to multiple mailboxes requires multiple + connections. The SELECT command automatically deselects any + currently selected mailbox before attempting the new selection. + Consequently, if a mailbox is selected and a SELECT command that + fails is attempted, no mailbox is selected. + + If the client is permitted to modify the mailbox, the server + SHOULD prefix the text of the tagged OK response with the + "[READ-WRITE]" response code. + + If the client is not permitted to modify the mailbox but is + permitted read access, the mailbox is selected as read-only, and + the server MUST prefix the text of the tagged OK response to + SELECT with the "[READ-ONLY]" response code. Read-only access + through SELECT differs from the EXAMINE command in that certain + read-only mailboxes MAY permit the change of permanent state on a + per-user (as opposed to global) basis. Netnews messages marked in + a server-based .newsrc file are an example of such per-user + permanent state that can be modified with read-only mailboxes. + + Example: C: A142 SELECT INBOX + S: * 172 EXISTS + S: * 1 RECENT + S: * OK [UNSEEN 12] Message 12 is first unseen + S: * OK [UIDVALIDITY 3857529045] UIDs valid + S: * OK [UIDNEXT 4392] Predicted next UID + S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) + S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited + S: A142 OK [READ-WRITE] SELECT completed + + + + + + + + + + + + + + + +Crispin Standards Track [Page 33] + +RFC 3501 IMAPv4 March 2003 + + +6.3.2. EXAMINE Command + + Arguments: mailbox name + + Responses: REQUIRED untagged responses: FLAGS, EXISTS, RECENT + REQUIRED OK untagged responses: UNSEEN, PERMANENTFLAGS, + UIDNEXT, UIDVALIDITY + + Result: OK - examine completed, now in selected state + NO - examine failure, now in authenticated state: no + such mailbox, can't access mailbox + BAD - command unknown or arguments invalid + + The EXAMINE command is identical to SELECT and returns the same + output; however, the selected mailbox is identified as read-only. + No changes to the permanent state of the mailbox, including + per-user state, are permitted; in particular, EXAMINE MUST NOT + cause messages to lose the \Recent flag. + + The text of the tagged OK response to the EXAMINE command MUST + begin with the "[READ-ONLY]" response code. + + Example: C: A932 EXAMINE blurdybloop + S: * 17 EXISTS + S: * 2 RECENT + S: * OK [UNSEEN 8] Message 8 is first unseen + S: * OK [UIDVALIDITY 3857529045] UIDs valid + S: * OK [UIDNEXT 4392] Predicted next UID + S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) + S: * OK [PERMANENTFLAGS ()] No permanent flags permitted + S: A932 OK [READ-ONLY] EXAMINE completed + + +6.3.3. CREATE Command + + Arguments: mailbox name + + Responses: no specific responses for this command + + Result: OK - create completed + NO - create failure: can't create mailbox with that name + BAD - command unknown or arguments invalid + + The CREATE command creates a mailbox with the given name. An OK + response is returned only if a new mailbox with that name has been + created. It is an error to attempt to create INBOX or a mailbox + with a name that refers to an extant mailbox. Any error in + creation will return a tagged NO response. + + + +Crispin Standards Track [Page 34] + +RFC 3501 IMAPv4 March 2003 + + + If the mailbox name is suffixed with the server's hierarchy + separator character (as returned from the server by a LIST + command), this is a declaration that the client intends to create + mailbox names under this name in the hierarchy. Server + implementations that do not require this declaration MUST ignore + the declaration. In any case, the name created is without the + trailing hierarchy delimiter. + + If the server's hierarchy separator character appears elsewhere in + the name, the server SHOULD create any superior hierarchical names + that are needed for the CREATE command to be successfully + completed. In other words, an attempt to create "foo/bar/zap" on + a server in which "/" is the hierarchy separator character SHOULD + create foo/ and foo/bar/ if they do not already exist. + + If a new mailbox is created with the same name as a mailbox which + was deleted, its unique identifiers MUST be greater than any + unique identifiers used in the previous incarnation of the mailbox + UNLESS the new incarnation has a different unique identifier + validity value. See the description of the UID command for more + detail. + + Example: C: A003 CREATE owatagusiam/ + S: A003 OK CREATE completed + C: A004 CREATE owatagusiam/blurdybloop + S: A004 OK CREATE completed + + Note: The interpretation of this example depends on whether + "/" was returned as the hierarchy separator from LIST. If + "/" is the hierarchy separator, a new level of hierarchy + named "owatagusiam" with a member called "blurdybloop" is + created. Otherwise, two mailboxes at the same hierarchy + level are created. + + +6.3.4. DELETE Command + + Arguments: mailbox name + + Responses: no specific responses for this command + + Result: OK - delete completed + NO - delete failure: can't delete mailbox with that name + BAD - command unknown or arguments invalid + + + + + + + +Crispin Standards Track [Page 35] + +RFC 3501 IMAPv4 March 2003 + + + The DELETE command permanently removes the mailbox with the given + name. A tagged OK response is returned only if the mailbox has + been deleted. It is an error to attempt to delete INBOX or a + mailbox name that does not exist. + + The DELETE command MUST NOT remove inferior hierarchical names. + For example, if a mailbox "foo" has an inferior "foo.bar" + (assuming "." is the hierarchy delimiter character), removing + "foo" MUST NOT remove "foo.bar". It is an error to attempt to + delete a name that has inferior hierarchical names and also has + the \Noselect mailbox name attribute (see the description of the + LIST response for more details). + + It is permitted to delete a name that has inferior hierarchical + names and does not have the \Noselect mailbox name attribute. In + this case, all messages in that mailbox are removed, and the name + will acquire the \Noselect mailbox name attribute. + + The value of the highest-used unique identifier of the deleted + mailbox MUST be preserved so that a new mailbox created with the + same name will not reuse the identifiers of the former + incarnation, UNLESS the new incarnation has a different unique + identifier validity value. See the description of the UID command + for more detail. + + Examples: C: A682 LIST "" * + S: * LIST () "/" blurdybloop + S: * LIST (\Noselect) "/" foo + S: * LIST () "/" foo/bar + S: A682 OK LIST completed + C: A683 DELETE blurdybloop + S: A683 OK DELETE completed + C: A684 DELETE foo + S: A684 NO Name "foo" has inferior hierarchical names + C: A685 DELETE foo/bar + S: A685 OK DELETE Completed + C: A686 LIST "" * + S: * LIST (\Noselect) "/" foo + S: A686 OK LIST completed + C: A687 DELETE foo + S: A687 OK DELETE Completed + + + + + + + + + + +Crispin Standards Track [Page 36] + +RFC 3501 IMAPv4 March 2003 + + + C: A82 LIST "" * + S: * LIST () "." blurdybloop + S: * LIST () "." foo + S: * LIST () "." foo.bar + S: A82 OK LIST completed + C: A83 DELETE blurdybloop + S: A83 OK DELETE completed + C: A84 DELETE foo + S: A84 OK DELETE Completed + C: A85 LIST "" * + S: * LIST () "." foo.bar + S: A85 OK LIST completed + C: A86 LIST "" % + S: * LIST (\Noselect) "." foo + S: A86 OK LIST completed + + +6.3.5. RENAME Command + + Arguments: existing mailbox name + new mailbox name + + Responses: no specific responses for this command + + Result: OK - rename completed + NO - rename failure: can't rename mailbox with that name, + can't rename to mailbox with that name + BAD - command unknown or arguments invalid + + The RENAME command changes the name of a mailbox. A tagged OK + response is returned only if the mailbox has been renamed. It is + an error to attempt to rename from a mailbox name that does not + exist or to a mailbox name that already exists. Any error in + renaming will return a tagged NO response. + + If the name has inferior hierarchical names, then the inferior + hierarchical names MUST also be renamed. For example, a rename of + "foo" to "zap" will rename "foo/bar" (assuming "/" is the + hierarchy delimiter character) to "zap/bar". + + If the server's hierarchy separator character appears in the name, + the server SHOULD create any superior hierarchical names that are + needed for the RENAME command to complete successfully. In other + words, an attempt to rename "foo/bar/zap" to baz/rag/zowie on a + server in which "/" is the hierarchy separator character SHOULD + create baz/ and baz/rag/ if they do not already exist. + + + + + +Crispin Standards Track [Page 37] + +RFC 3501 IMAPv4 March 2003 + + + The value of the highest-used unique identifier of the old mailbox + name MUST be preserved so that a new mailbox created with the same + name will not reuse the identifiers of the former incarnation, + UNLESS the new incarnation has a different unique identifier + validity value. See the description of the UID command for more + detail. + + Renaming INBOX is permitted, and has special behavior. It moves + all messages in INBOX to a new mailbox with the given name, + leaving INBOX empty. If the server implementation supports + inferior hierarchical names of INBOX, these are unaffected by a + rename of INBOX. + + Examples: C: A682 LIST "" * + S: * LIST () "/" blurdybloop + S: * LIST (\Noselect) "/" foo + S: * LIST () "/" foo/bar + S: A682 OK LIST completed + C: A683 RENAME blurdybloop sarasoop + S: A683 OK RENAME completed + C: A684 RENAME foo zowie + S: A684 OK RENAME Completed + C: A685 LIST "" * + S: * LIST () "/" sarasoop + S: * LIST (\Noselect) "/" zowie + S: * LIST () "/" zowie/bar + S: A685 OK LIST completed + + C: Z432 LIST "" * + S: * LIST () "." INBOX + S: * LIST () "." INBOX.bar + S: Z432 OK LIST completed + C: Z433 RENAME INBOX old-mail + S: Z433 OK RENAME completed + C: Z434 LIST "" * + S: * LIST () "." INBOX + S: * LIST () "." INBOX.bar + S: * LIST () "." old-mail + S: Z434 OK LIST completed + + + + + + + + + + + + +Crispin Standards Track [Page 38] + +RFC 3501 IMAPv4 March 2003 + + +6.3.6. SUBSCRIBE Command + + Arguments: mailbox + + Responses: no specific responses for this command + + Result: OK - subscribe completed + NO - subscribe failure: can't subscribe to that name + BAD - command unknown or arguments invalid + + The SUBSCRIBE command adds the specified mailbox name to the + server's set of "active" or "subscribed" mailboxes as returned by + the LSUB command. This command returns a tagged OK response only + if the subscription is successful. + + A server MAY validate the mailbox argument to SUBSCRIBE to verify + that it exists. However, it MUST NOT unilaterally remove an + existing mailbox name from the subscription list even if a mailbox + by that name no longer exists. + + Note: This requirement is because a server site can + choose to routinely remove a mailbox with a well-known + name (e.g., "system-alerts") after its contents expire, + with the intention of recreating it when new contents + are appropriate. + + + Example: C: A002 SUBSCRIBE #news.comp.mail.mime + S: A002 OK SUBSCRIBE completed + + +6.3.7. UNSUBSCRIBE Command + + Arguments: mailbox name + + Responses: no specific responses for this command + + Result: OK - unsubscribe completed + NO - unsubscribe failure: can't unsubscribe that name + BAD - command unknown or arguments invalid + + The UNSUBSCRIBE command removes the specified mailbox name from + the server's set of "active" or "subscribed" mailboxes as returned + by the LSUB command. This command returns a tagged OK response + only if the unsubscription is successful. + + Example: C: A002 UNSUBSCRIBE #news.comp.mail.mime + S: A002 OK UNSUBSCRIBE completed + + + +Crispin Standards Track [Page 39] + +RFC 3501 IMAPv4 March 2003 + + +6.3.8. LIST Command + + Arguments: reference name + mailbox name with possible wildcards + + Responses: untagged responses: LIST + + Result: OK - list completed + NO - list failure: can't list that reference or name + BAD - command unknown or arguments invalid + + The LIST command returns a subset of names from the complete set + of all names available to the client. Zero or more untagged LIST + replies are returned, containing the name attributes, hierarchy + delimiter, and name; see the description of the LIST reply for + more detail. + + The LIST command SHOULD return its data quickly, without undue + delay. For example, it SHOULD NOT go to excess trouble to + calculate the \Marked or \Unmarked status or perform other + processing; if each name requires 1 second of processing, then a + list of 1200 names would take 20 minutes! + + An empty ("" string) reference name argument indicates that the + mailbox name is interpreted as by SELECT. The returned mailbox + names MUST match the supplied mailbox name pattern. A non-empty + reference name argument is the name of a mailbox or a level of + mailbox hierarchy, and indicates the context in which the mailbox + name is interpreted. + + An empty ("" string) mailbox name argument is a special request to + return the hierarchy delimiter and the root name of the name given + in the reference. The value returned as the root MAY be the empty + string if the reference is non-rooted or is an empty string. In + all cases, a hierarchy delimiter (or NIL if there is no hierarchy) + is returned. This permits a client to get the hierarchy delimiter + (or find out that the mailbox names are flat) even when no + mailboxes by that name currently exist. + + The reference and mailbox name arguments are interpreted into a + canonical form that represents an unambiguous left-to-right + hierarchy. The returned mailbox names will be in the interpreted + form. + + + + + + + + +Crispin Standards Track [Page 40] + +RFC 3501 IMAPv4 March 2003 + + + Note: The interpretation of the reference argument is + implementation-defined. It depends upon whether the + server implementation has a concept of the "current + working directory" and leading "break out characters", + which override the current working directory. + + For example, on a server which exports a UNIX or NT + filesystem, the reference argument contains the current + working directory, and the mailbox name argument would + contain the name as interpreted in the current working + directory. + + If a server implementation has no concept of break out + characters, the canonical form is normally the reference + name appended with the mailbox name. Note that if the + server implements the namespace convention (section + 5.1.2), "#" is a break out character and must be treated + as such. + + If the reference argument is not a level of mailbox + hierarchy (that is, it is a \NoInferiors name), and/or + the reference argument does not end with the hierarchy + delimiter, it is implementation-dependent how this is + interpreted. For example, a reference of "foo/bar" and + mailbox name of "rag/baz" could be interpreted as + "foo/bar/rag/baz", "foo/barrag/baz", or "foo/rag/baz". + A client SHOULD NOT use such a reference argument except + at the explicit request of the user. A hierarchical + browser MUST NOT make any assumptions about server + interpretation of the reference unless the reference is + a level of mailbox hierarchy AND ends with the hierarchy + delimiter. + + Any part of the reference argument that is included in the + interpreted form SHOULD prefix the interpreted form. It SHOULD + also be in the same form as the reference name argument. This + rule permits the client to determine if the returned mailbox name + is in the context of the reference argument, or if something about + the mailbox argument overrode the reference argument. Without + this rule, the client would have to have knowledge of the server's + naming semantics including what characters are "breakouts" that + override a naming context. + + + + + + + + + +Crispin Standards Track [Page 41] + +RFC 3501 IMAPv4 March 2003 + + + For example, here are some examples of how references + and mailbox names might be interpreted on a UNIX-based + server: + + Reference Mailbox Name Interpretation + ------------ ------------ -------------- + ~smith/Mail/ foo.* ~smith/Mail/foo.* + archive/ % archive/% + #news. comp.mail.* #news.comp.mail.* + ~smith/Mail/ /usr/doc/foo /usr/doc/foo + archive/ ~fred/Mail/* ~fred/Mail/* + + The first three examples demonstrate interpretations in + the context of the reference argument. Note that + "~smith/Mail" SHOULD NOT be transformed into something + like "/u2/users/smith/Mail", or it would be impossible + for the client to determine that the interpretation was + in the context of the reference. + + The character "*" is a wildcard, and matches zero or more + characters at this position. The character "%" is similar to "*", + but it does not match a hierarchy delimiter. If the "%" wildcard + is the last character of a mailbox name argument, matching levels + of hierarchy are also returned. If these levels of hierarchy are + not also selectable mailboxes, they are returned with the + \Noselect mailbox name attribute (see the description of the LIST + response for more details). + + Server implementations are permitted to "hide" otherwise + accessible mailboxes from the wildcard characters, by preventing + certain characters or names from matching a wildcard in certain + situations. For example, a UNIX-based server might restrict the + interpretation of "*" so that an initial "/" character does not + match. + + The special name INBOX is included in the output from LIST, if + INBOX is supported by this server for this user and if the + uppercase string "INBOX" matches the interpreted reference and + mailbox name arguments with wildcards as described above. The + criteria for omitting INBOX is whether SELECT INBOX will return + failure; it is not relevant whether the user's real INBOX resides + on this or some other server. + + + + + + + + + +Crispin Standards Track [Page 42] + +RFC 3501 IMAPv4 March 2003 + + + Example: C: A101 LIST "" "" + S: * LIST (\Noselect) "/" "" + S: A101 OK LIST Completed + C: A102 LIST #news.comp.mail.misc "" + S: * LIST (\Noselect) "." #news. + S: A102 OK LIST Completed + C: A103 LIST /usr/staff/jones "" + S: * LIST (\Noselect) "/" / + S: A103 OK LIST Completed + C: A202 LIST ~/Mail/ % + S: * LIST (\Noselect) "/" ~/Mail/foo + S: * LIST () "/" ~/Mail/meetings + S: A202 OK LIST completed + + +6.3.9. LSUB Command + + Arguments: reference name + mailbox name with possible wildcards + + Responses: untagged responses: LSUB + + Result: OK - lsub completed + NO - lsub failure: can't list that reference or name + BAD - command unknown or arguments invalid + + The LSUB command returns a subset of names from the set of names + that the user has declared as being "active" or "subscribed". + Zero or more untagged LSUB replies are returned. The arguments to + LSUB are in the same form as those for LIST. + + The returned untagged LSUB response MAY contain different mailbox + flags from a LIST untagged response. If this should happen, the + flags in the untagged LIST are considered more authoritative. + + A special situation occurs when using LSUB with the % wildcard. + Consider what happens if "foo/bar" (with a hierarchy delimiter of + "/") is subscribed but "foo" is not. A "%" wildcard to LSUB must + return foo, not foo/bar, in the LSUB response, and it MUST be + flagged with the \Noselect attribute. + + The server MUST NOT unilaterally remove an existing mailbox name + from the subscription list even if a mailbox by that name no + longer exists. + + + + + + + +Crispin Standards Track [Page 43] + +RFC 3501 IMAPv4 March 2003 + + + Example: C: A002 LSUB "#news." "comp.mail.*" + S: * LSUB () "." #news.comp.mail.mime + S: * LSUB () "." #news.comp.mail.misc + S: A002 OK LSUB completed + C: A003 LSUB "#news." "comp.%" + S: * LSUB (\NoSelect) "." #news.comp.mail + S: A003 OK LSUB completed + + +6.3.10. STATUS Command + + Arguments: mailbox name + status data item names + + Responses: untagged responses: STATUS + + Result: OK - status completed + NO - status failure: no status for that name + BAD - command unknown or arguments invalid + + The STATUS command requests the status of the indicated mailbox. + It does not change the currently selected mailbox, nor does it + affect the state of any messages in the queried mailbox (in + particular, STATUS MUST NOT cause messages to lose the \Recent + flag). + + The STATUS command provides an alternative to opening a second + IMAP4rev1 connection and doing an EXAMINE command on a mailbox to + query that mailbox's status without deselecting the current + mailbox in the first IMAP4rev1 connection. + + Unlike the LIST command, the STATUS command is not guaranteed to + be fast in its response. Under certain circumstances, it can be + quite slow. In some implementations, the server is obliged to + open the mailbox read-only internally to obtain certain status + information. Also unlike the LIST command, the STATUS command + does not accept wildcards. + + Note: The STATUS command is intended to access the + status of mailboxes other than the currently selected + mailbox. Because the STATUS command can cause the + mailbox to be opened internally, and because this + information is available by other means on the selected + mailbox, the STATUS command SHOULD NOT be used on the + currently selected mailbox. + + + + + + +Crispin Standards Track [Page 44] + +RFC 3501 IMAPv4 March 2003 + + + The STATUS command MUST NOT be used as a "check for new + messages in the selected mailbox" operation (refer to + sections 7, 7.3.1, and 7.3.2 for more information about + the proper method for new message checking). + + Because the STATUS command is not guaranteed to be fast + in its results, clients SHOULD NOT expect to be able to + issue many consecutive STATUS commands and obtain + reasonable performance. + + The currently defined status data items that can be requested are: + + MESSAGES + The number of messages in the mailbox. + + RECENT + The number of messages with the \Recent flag set. + + UIDNEXT + The next unique identifier value of the mailbox. Refer to + section 2.3.1.1 for more information. + + UIDVALIDITY + The unique identifier validity value of the mailbox. Refer to + section 2.3.1.1 for more information. + + UNSEEN + The number of messages which do not have the \Seen flag set. + + + Example: C: A042 STATUS blurdybloop (UIDNEXT MESSAGES) + S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292) + S: A042 OK STATUS completed + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 45] + +RFC 3501 IMAPv4 March 2003 + + +6.3.11. APPEND Command + + Arguments: mailbox name + OPTIONAL flag parenthesized list + OPTIONAL date/time string + message literal + + Responses: no specific responses for this command + + Result: OK - append completed + NO - append error: can't append to that mailbox, error + in flags or date/time or message text + BAD - command unknown or arguments invalid + + The APPEND command appends the literal argument as a new message + to the end of the specified destination mailbox. This argument + SHOULD be in the format of an [RFC-2822] message. 8-bit + characters are permitted in the message. A server implementation + that is unable to preserve 8-bit data properly MUST be able to + reversibly convert 8-bit APPEND data to 7-bit using a [MIME-IMB] + content transfer encoding. + + Note: There MAY be exceptions, e.g., draft messages, in + which required [RFC-2822] header lines are omitted in + the message literal argument to APPEND. The full + implications of doing so MUST be understood and + carefully weighed. + + If a flag parenthesized list is specified, the flags SHOULD be set + in the resulting message; otherwise, the flag list of the + resulting message is set to empty by default. In either case, the + Recent flag is also set. + + If a date-time is specified, the internal date SHOULD be set in + the resulting message; otherwise, the internal date of the + resulting message is set to the current date and time by default. + + If the append is unsuccessful for any reason, the mailbox MUST be + restored to its state before the APPEND attempt; no partial + appending is permitted. + + If the destination mailbox does not exist, a server MUST return an + error, and MUST NOT automatically create the mailbox. Unless it + is certain that the destination mailbox can not be created, the + server MUST send the response code "[TRYCREATE]" as the prefix of + the text of the tagged NO response. This gives a hint to the + client that it can attempt a CREATE command and retry the APPEND + if the CREATE is successful. + + + +Crispin Standards Track [Page 46] + +RFC 3501 IMAPv4 March 2003 + + + If the mailbox is currently selected, the normal new message + actions SHOULD occur. Specifically, the server SHOULD notify the + client immediately via an untagged EXISTS response. If the server + does not do so, the client MAY issue a NOOP command (or failing + that, a CHECK command) after one or more APPEND commands. + + Example: C: A003 APPEND saved-messages (\Seen) {310} + S: + Ready for literal data + C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST) + C: From: Fred Foobar <foobar@Blurdybloop.COM> + C: Subject: afternoon meeting + C: To: mooch@owatagu.siam.edu + C: Message-Id: <B27397-0100000@Blurdybloop.COM> + C: MIME-Version: 1.0 + C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII + C: + C: Hello Joe, do you think we can meet at 3:30 tomorrow? + C: + S: A003 OK APPEND completed + + Note: The APPEND command is not used for message delivery, + because it does not provide a mechanism to transfer [SMTP] + envelope information. + +6.4. Client Commands - Selected State + + In the selected state, commands that manipulate messages in a mailbox + are permitted. + + In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), + and the authenticated state commands (SELECT, EXAMINE, CREATE, + DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, LSUB, STATUS, and + APPEND), the following commands are valid in the selected state: + CHECK, CLOSE, EXPUNGE, SEARCH, FETCH, STORE, COPY, and UID. + +6.4.1. CHECK Command + + Arguments: none + + Responses: no specific responses for this command + + Result: OK - check completed + BAD - command unknown or arguments invalid + + The CHECK command requests a checkpoint of the currently selected + mailbox. A checkpoint refers to any implementation-dependent + housekeeping associated with the mailbox (e.g., resolving the + server's in-memory state of the mailbox with the state on its + + + +Crispin Standards Track [Page 47] + +RFC 3501 IMAPv4 March 2003 + + + disk) that is not normally executed as part of each command. A + checkpoint MAY take a non-instantaneous amount of real time to + complete. If a server implementation has no such housekeeping + considerations, CHECK is equivalent to NOOP. + + There is no guarantee that an EXISTS untagged response will happen + as a result of CHECK. NOOP, not CHECK, SHOULD be used for new + message polling. + + Example: C: FXXZ CHECK + S: FXXZ OK CHECK Completed + + +6.4.2. CLOSE Command + + Arguments: none + + Responses: no specific responses for this command + + Result: OK - close completed, now in authenticated state + BAD - command unknown or arguments invalid + + The CLOSE command permanently removes all messages that have the + \Deleted flag set from the currently selected mailbox, and returns + to the authenticated state from the selected state. No untagged + EXPUNGE responses are sent. + + No messages are removed, and no error is given, if the mailbox is + selected by an EXAMINE command or is otherwise selected read-only. + + Even if a mailbox is selected, a SELECT, EXAMINE, or LOGOUT + command MAY be issued without previously issuing a CLOSE command. + The SELECT, EXAMINE, and LOGOUT commands implicitly close the + currently selected mailbox without doing an expunge. However, + when many messages are deleted, a CLOSE-LOGOUT or CLOSE-SELECT + sequence is considerably faster than an EXPUNGE-LOGOUT or + EXPUNGE-SELECT because no untagged EXPUNGE responses (which the + client would probably ignore) are sent. + + Example: C: A341 CLOSE + S: A341 OK CLOSE completed + + + + + + + + + + +Crispin Standards Track [Page 48] + +RFC 3501 IMAPv4 March 2003 + + +6.4.3. EXPUNGE Command + + Arguments: none + + Responses: untagged responses: EXPUNGE + + Result: OK - expunge completed + NO - expunge failure: can't expunge (e.g., permission + denied) + BAD - command unknown or arguments invalid + + The EXPUNGE command permanently removes all messages that have the + \Deleted flag set from the currently selected mailbox. Before + returning an OK to the client, an untagged EXPUNGE response is + sent for each message that is removed. + + Example: C: A202 EXPUNGE + S: * 3 EXPUNGE + S: * 3 EXPUNGE + S: * 5 EXPUNGE + S: * 8 EXPUNGE + S: A202 OK EXPUNGE completed + + Note: In this example, messages 3, 4, 7, and 11 had the + \Deleted flag set. See the description of the EXPUNGE + response for further explanation. + + +6.4.4. SEARCH Command + + Arguments: OPTIONAL [CHARSET] specification + searching criteria (one or more) + + Responses: REQUIRED untagged response: SEARCH + + Result: OK - search completed + NO - search error: can't search that [CHARSET] or + criteria + BAD - command unknown or arguments invalid + + The SEARCH command searches the mailbox for messages that match + the given searching criteria. Searching criteria consist of one + or more search keys. The untagged SEARCH response from the server + contains a listing of message sequence numbers corresponding to + those messages that match the searching criteria. + + + + + + +Crispin Standards Track [Page 49] + +RFC 3501 IMAPv4 March 2003 + + + When multiple keys are specified, the result is the intersection + (AND function) of all the messages that match those keys. For + example, the criteria DELETED FROM "SMITH" SINCE 1-Feb-1994 refers + to all deleted messages from Smith that were placed in the mailbox + since February 1, 1994. A search key can also be a parenthesized + list of one or more search keys (e.g., for use with the OR and NOT + keys). + + Server implementations MAY exclude [MIME-IMB] body parts with + terminal content media types other than TEXT and MESSAGE from + consideration in SEARCH matching. + + The OPTIONAL [CHARSET] specification consists of the word + "CHARSET" followed by a registered [CHARSET]. It indicates the + [CHARSET] of the strings that appear in the search criteria. + [MIME-IMB] content transfer encodings, and [MIME-HDRS] strings in + [RFC-2822]/[MIME-IMB] headers, MUST be decoded before comparing + text in a [CHARSET] other than US-ASCII. US-ASCII MUST be + supported; other [CHARSET]s MAY be supported. + + If the server does not support the specified [CHARSET], it MUST + return a tagged NO response (not a BAD). This response SHOULD + contain the BADCHARSET response code, which MAY list the + [CHARSET]s supported by the server. + + In all search keys that use strings, a message matches the key if + the string is a substring of the field. The matching is + case-insensitive. + + The defined search keys are as follows. Refer to the Formal + Syntax section for the precise syntactic definitions of the + arguments. + + <sequence set> + Messages with message sequence numbers corresponding to the + specified message sequence number set. + + ALL + All messages in the mailbox; the default initial key for + ANDing. + + ANSWERED + Messages with the \Answered flag set. + + + + + + + + +Crispin Standards Track [Page 50] + +RFC 3501 IMAPv4 March 2003 + + + BCC <string> + Messages that contain the specified string in the envelope + structure's BCC field. + + BEFORE <date> + Messages whose internal date (disregarding time and timezone) + is earlier than the specified date. + + BODY <string> + Messages that contain the specified string in the body of the + message. + + CC <string> + Messages that contain the specified string in the envelope + structure's CC field. + + DELETED + Messages with the \Deleted flag set. + + DRAFT + Messages with the \Draft flag set. + + FLAGGED + Messages with the \Flagged flag set. + + FROM <string> + Messages that contain the specified string in the envelope + structure's FROM field. + + HEADER <field-name> <string> + Messages that have a header with the specified field-name (as + defined in [RFC-2822]) and that contains the specified string + in the text of the header (what comes after the colon). If the + string to search is zero-length, this matches all messages that + have a header line with the specified field-name regardless of + the contents. + + KEYWORD <flag> + Messages with the specified keyword flag set. + + LARGER <n> + Messages with an [RFC-2822] size larger than the specified + number of octets. + + NEW + Messages that have the \Recent flag set but not the \Seen flag. + This is functionally equivalent to "(RECENT UNSEEN)". + + + + +Crispin Standards Track [Page 51] + +RFC 3501 IMAPv4 March 2003 + + + NOT <search-key> + Messages that do not match the specified search key. + + OLD + Messages that do not have the \Recent flag set. This is + functionally equivalent to "NOT RECENT" (as opposed to "NOT + NEW"). + + ON <date> + Messages whose internal date (disregarding time and timezone) + is within the specified date. + + OR <search-key1> <search-key2> + Messages that match either search key. + + RECENT + Messages that have the \Recent flag set. + + SEEN + Messages that have the \Seen flag set. + + SENTBEFORE <date> + Messages whose [RFC-2822] Date: header (disregarding time and + timezone) is earlier than the specified date. + + SENTON <date> + Messages whose [RFC-2822] Date: header (disregarding time and + timezone) is within the specified date. + + SENTSINCE <date> + Messages whose [RFC-2822] Date: header (disregarding time and + timezone) is within or later than the specified date. + + SINCE <date> + Messages whose internal date (disregarding time and timezone) + is within or later than the specified date. + + SMALLER <n> + Messages with an [RFC-2822] size smaller than the specified + number of octets. + + + + + + + + + + + +Crispin Standards Track [Page 52] + +RFC 3501 IMAPv4 March 2003 + + + SUBJECT <string> + Messages that contain the specified string in the envelope + structure's SUBJECT field. + + TEXT <string> + Messages that contain the specified string in the header or + body of the message. + + TO <string> + Messages that contain the specified string in the envelope + structure's TO field. + + UID <sequence set> + Messages with unique identifiers corresponding to the specified + unique identifier set. Sequence set ranges are permitted. + + UNANSWERED + Messages that do not have the \Answered flag set. + + UNDELETED + Messages that do not have the \Deleted flag set. + + UNDRAFT + Messages that do not have the \Draft flag set. + + UNFLAGGED + Messages that do not have the \Flagged flag set. + + UNKEYWORD <flag> + Messages that do not have the specified keyword flag set. + + UNSEEN + Messages that do not have the \Seen flag set. + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 53] + +RFC 3501 IMAPv4 March 2003 + + + Example: C: A282 SEARCH FLAGGED SINCE 1-Feb-1994 NOT FROM "Smith" + S: * SEARCH 2 84 882 + S: A282 OK SEARCH completed + C: A283 SEARCH TEXT "string not in mailbox" + S: * SEARCH + S: A283 OK SEARCH completed + C: A284 SEARCH CHARSET UTF-8 TEXT {6} + C: XXXXXX + S: * SEARCH 43 + S: A284 OK SEARCH completed + + Note: Since this document is restricted to 7-bit ASCII + text, it is not possible to show actual UTF-8 data. The + "XXXXXX" is a placeholder for what would be 6 octets of + 8-bit data in an actual transaction. + + +6.4.5. FETCH Command + + Arguments: sequence set + message data item names or macro + + Responses: untagged responses: FETCH + + Result: OK - fetch completed + NO - fetch error: can't fetch that data + BAD - command unknown or arguments invalid + + The FETCH command retrieves data associated with a message in the + mailbox. The data items to be fetched can be either a single atom + or a parenthesized list. + + Most data items, identified in the formal syntax under the + msg-att-static rule, are static and MUST NOT change for any + particular message. Other data items, identified in the formal + syntax under the msg-att-dynamic rule, MAY change, either as a + result of a STORE command or due to external events. + + For example, if a client receives an ENVELOPE for a + message when it already knows the envelope, it can + safely ignore the newly transmitted envelope. + + There are three macros which specify commonly-used sets of data + items, and can be used instead of data items. A macro must be + used by itself, and not in conjunction with other macros or data + items. + + + + + +Crispin Standards Track [Page 54] + +RFC 3501 IMAPv4 March 2003 + + + ALL + Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE) + + FAST + Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE) + + FULL + Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE + BODY) + + The currently defined data items that can be fetched are: + + BODY + Non-extensible form of BODYSTRUCTURE. + + BODY[<section>]<<partial>> + The text of a particular body section. The section + specification is a set of zero or more part specifiers + delimited by periods. A part specifier is either a part number + or one of the following: HEADER, HEADER.FIELDS, + HEADER.FIELDS.NOT, MIME, and TEXT. An empty section + specification refers to the entire message, including the + header. + + Every message has at least one part number. Non-[MIME-IMB] + messages, and non-multipart [MIME-IMB] messages with no + encapsulated message, only have a part 1. + + Multipart messages are assigned consecutive part numbers, as + they occur in the message. If a particular part is of type + message or multipart, its parts MUST be indicated by a period + followed by the part number within that nested multipart part. + + A part of type MESSAGE/RFC822 also has nested part numbers, + referring to parts of the MESSAGE part's body. + + The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, and TEXT part + specifiers can be the sole part specifier or can be prefixed by + one or more numeric part specifiers, provided that the numeric + part specifier refers to a part of type MESSAGE/RFC822. The + MIME part specifier MUST be prefixed by one or more numeric + part specifiers. + + The HEADER, HEADER.FIELDS, and HEADER.FIELDS.NOT part + specifiers refer to the [RFC-2822] header of the message or of + an encapsulated [MIME-IMT] MESSAGE/RFC822 message. + HEADER.FIELDS and HEADER.FIELDS.NOT are followed by a list of + field-name (as defined in [RFC-2822]) names, and return a + + + +Crispin Standards Track [Page 55] + +RFC 3501 IMAPv4 March 2003 + + + subset of the header. The subset returned by HEADER.FIELDS + contains only those header fields with a field-name that + matches one of the names in the list; similarly, the subset + returned by HEADER.FIELDS.NOT contains only the header fields + with a non-matching field-name. The field-matching is + case-insensitive but otherwise exact. Subsetting does not + exclude the [RFC-2822] delimiting blank line between the header + and the body; the blank line is included in all header fetches, + except in the case of a message which has no body and no blank + line. + + The MIME part specifier refers to the [MIME-IMB] header for + this part. + + The TEXT part specifier refers to the text body of the message, + omitting the [RFC-2822] header. + + Here is an example of a complex message with some of its + part specifiers: + + HEADER ([RFC-2822] header of the message) + TEXT ([RFC-2822] text body of the message) MULTIPART/MIXED + 1 TEXT/PLAIN + 2 APPLICATION/OCTET-STREAM + 3 MESSAGE/RFC822 + 3.HEADER ([RFC-2822] header of the message) + 3.TEXT ([RFC-2822] text body of the message) MULTIPART/MIXED + 3.1 TEXT/PLAIN + 3.2 APPLICATION/OCTET-STREAM + 4 MULTIPART/MIXED + 4.1 IMAGE/GIF + 4.1.MIME ([MIME-IMB] header for the IMAGE/GIF) + 4.2 MESSAGE/RFC822 + 4.2.HEADER ([RFC-2822] header of the message) + 4.2.TEXT ([RFC-2822] text body of the message) MULTIPART/MIXED + 4.2.1 TEXT/PLAIN + 4.2.2 MULTIPART/ALTERNATIVE + 4.2.2.1 TEXT/PLAIN + 4.2.2.2 TEXT/RICHTEXT + + + It is possible to fetch a substring of the designated text. + This is done by appending an open angle bracket ("<"), the + octet position of the first desired octet, a period, the + maximum number of octets desired, and a close angle bracket + (">") to the part specifier. If the starting octet is beyond + the end of the text, an empty string is returned. + + + + +Crispin Standards Track [Page 56] + +RFC 3501 IMAPv4 March 2003 + + + Any partial fetch that attempts to read beyond the end of the + text is truncated as appropriate. A partial fetch that starts + at octet 0 is returned as a partial fetch, even if this + truncation happened. + + Note: This means that BODY[]<0.2048> of a 1500-octet message + will return BODY[]<0> with a literal of size 1500, not + BODY[]. + + Note: A substring fetch of a HEADER.FIELDS or + HEADER.FIELDS.NOT part specifier is calculated after + subsetting the header. + + The \Seen flag is implicitly set; if this causes the flags to + change, they SHOULD be included as part of the FETCH responses. + + BODY.PEEK[<section>]<<partial>> + An alternate form of BODY[<section>] that does not implicitly + set the \Seen flag. + + BODYSTRUCTURE + The [MIME-IMB] body structure of the message. This is computed + by the server by parsing the [MIME-IMB] header fields in the + [RFC-2822] header and [MIME-IMB] headers. + + ENVELOPE + The envelope structure of the message. This is computed by the + server by parsing the [RFC-2822] header into the component + parts, defaulting various fields as necessary. + + FLAGS + The flags that are set for this message. + + INTERNALDATE + The internal date of the message. + + RFC822 + Functionally equivalent to BODY[], differing in the syntax of + the resulting untagged FETCH data (RFC822 is returned). + + RFC822.HEADER + Functionally equivalent to BODY.PEEK[HEADER], differing in the + syntax of the resulting untagged FETCH data (RFC822.HEADER is + returned). + + RFC822.SIZE + The [RFC-2822] size of the message. + + + + +Crispin Standards Track [Page 57] + +RFC 3501 IMAPv4 March 2003 + + + RFC822.TEXT + Functionally equivalent to BODY[TEXT], differing in the syntax + of the resulting untagged FETCH data (RFC822.TEXT is returned). + + UID + The unique identifier for the message. + + + Example: C: A654 FETCH 2:4 (FLAGS BODY[HEADER.FIELDS (DATE FROM)]) + S: * 2 FETCH .... + S: * 3 FETCH .... + S: * 4 FETCH .... + S: A654 OK FETCH completed + + +6.4.6. STORE Command + + Arguments: sequence set + message data item name + value for message data item + + Responses: untagged responses: FETCH + + Result: OK - store completed + NO - store error: can't store that data + BAD - command unknown or arguments invalid + + The STORE command alters data associated with a message in the + mailbox. Normally, STORE will return the updated value of the + data with an untagged FETCH response. A suffix of ".SILENT" in + the data item name prevents the untagged FETCH, and the server + SHOULD assume that the client has determined the updated value + itself or does not care about the updated value. + + Note: Regardless of whether or not the ".SILENT" suffix + was used, the server SHOULD send an untagged FETCH + response if a change to a message's flags from an + external source is observed. The intent is that the + status of the flags is determinate without a race + condition. + + + + + + + + + + + +Crispin Standards Track [Page 58] + +RFC 3501 IMAPv4 March 2003 + + + The currently defined data items that can be stored are: + + FLAGS <flag list> + Replace the flags for the message (other than \Recent) with the + argument. The new value of the flags is returned as if a FETCH + of those flags was done. + + FLAGS.SILENT <flag list> + Equivalent to FLAGS, but without returning a new value. + + +FLAGS <flag list> + Add the argument to the flags for the message. The new value + of the flags is returned as if a FETCH of those flags was done. + + +FLAGS.SILENT <flag list> + Equivalent to +FLAGS, but without returning a new value. + + -FLAGS <flag list> + Remove the argument from the flags for the message. The new + value of the flags is returned as if a FETCH of those flags was + done. + + -FLAGS.SILENT <flag list> + Equivalent to -FLAGS, but without returning a new value. + + + Example: C: A003 STORE 2:4 +FLAGS (\Deleted) + S: * 2 FETCH (FLAGS (\Deleted \Seen)) + S: * 3 FETCH (FLAGS (\Deleted)) + S: * 4 FETCH (FLAGS (\Deleted \Flagged \Seen)) + S: A003 OK STORE completed + + +6.4.7. COPY Command + + Arguments: sequence set + mailbox name + + Responses: no specific responses for this command + + Result: OK - copy completed + NO - copy error: can't copy those messages or to that + name + BAD - command unknown or arguments invalid + + + + + + + +Crispin Standards Track [Page 59] + +RFC 3501 IMAPv4 March 2003 + + + The COPY command copies the specified message(s) to the end of the + specified destination mailbox. The flags and internal date of the + message(s) SHOULD be preserved, and the Recent flag SHOULD be set, + in the copy. + + If the destination mailbox does not exist, a server SHOULD return + an error. It SHOULD NOT automatically create the mailbox. Unless + it is certain that the destination mailbox can not be created, the + server MUST send the response code "[TRYCREATE]" as the prefix of + the text of the tagged NO response. This gives a hint to the + client that it can attempt a CREATE command and retry the COPY if + the CREATE is successful. + + If the COPY command is unsuccessful for any reason, server + implementations MUST restore the destination mailbox to its state + before the COPY attempt. + + Example: C: A003 COPY 2:4 MEETING + S: A003 OK COPY completed + + +6.4.8. UID Command + + Arguments: command name + command arguments + + Responses: untagged responses: FETCH, SEARCH + + Result: OK - UID command completed + NO - UID command error + BAD - command unknown or arguments invalid + + The UID command has two forms. In the first form, it takes as its + arguments a COPY, FETCH, or STORE command with arguments + appropriate for the associated command. However, the numbers in + the sequence set argument are unique identifiers instead of + message sequence numbers. Sequence set ranges are permitted, but + there is no guarantee that unique identifiers will be contiguous. + + A non-existent unique identifier is ignored without any error + message generated. Thus, it is possible for a UID FETCH command + to return an OK without any data or a UID COPY or UID STORE to + return an OK without performing any operations. + + In the second form, the UID command takes a SEARCH command with + SEARCH command arguments. The interpretation of the arguments is + the same as with SEARCH; however, the numbers returned in a SEARCH + response for a UID SEARCH command are unique identifiers instead + + + +Crispin Standards Track [Page 60] + +RFC 3501 IMAPv4 March 2003 + + + of message sequence numbers. For example, the command UID SEARCH + 1:100 UID 443:557 returns the unique identifiers corresponding to + the intersection of two sequence sets, the message sequence number + range 1:100 and the UID range 443:557. + + Note: in the above example, the UID range 443:557 + appears. The same comment about a non-existent unique + identifier being ignored without any error message also + applies here. Hence, even if neither UID 443 or 557 + exist, this range is valid and would include an existing + UID 495. + + Also note that a UID range of 559:* always includes the + UID of the last message in the mailbox, even if 559 is + higher than any assigned UID value. This is because the + contents of a range are independent of the order of the + range endpoints. Thus, any UID range with * as one of + the endpoints indicates at least one message (the + message with the highest numbered UID), unless the + mailbox is empty. + + The number after the "*" in an untagged FETCH response is always a + message sequence number, not a unique identifier, even for a UID + command response. However, server implementations MUST implicitly + include the UID message data item as part of any FETCH response + caused by a UID command, regardless of whether a UID was specified + as a message data item to the FETCH. + + + Note: The rule about including the UID message data item as part + of a FETCH response primarily applies to the UID FETCH and UID + STORE commands, including a UID FETCH command that does not + include UID as a message data item. Although it is unlikely that + the other UID commands will cause an untagged FETCH, this rule + applies to these commands as well. + + Example: C: A999 UID FETCH 4827313:4828442 FLAGS + S: * 23 FETCH (FLAGS (\Seen) UID 4827313) + S: * 24 FETCH (FLAGS (\Seen) UID 4827943) + S: * 25 FETCH (FLAGS (\Seen) UID 4828442) + S: A999 OK UID FETCH completed + + + + + + + + + + +Crispin Standards Track [Page 61] + +RFC 3501 IMAPv4 March 2003 + + +6.5. Client Commands - Experimental/Expansion + + +6.5.1. X<atom> Command + + Arguments: implementation defined + + Responses: implementation defined + + Result: OK - command completed + NO - failure + BAD - command unknown or arguments invalid + + Any command prefixed with an X is an experimental command. + Commands which are not part of this specification, a standard or + standards-track revision of this specification, or an + IESG-approved experimental protocol, MUST use the X prefix. + + Any added untagged responses issued by an experimental command + MUST also be prefixed with an X. Server implementations MUST NOT + send any such untagged responses, unless the client requested it + by issuing the associated experimental command. + + Example: C: a441 CAPABILITY + S: * CAPABILITY IMAP4rev1 XPIG-LATIN + S: a441 OK CAPABILITY completed + C: A442 XPIG-LATIN + S: * XPIG-LATIN ow-nay eaking-spay ig-pay atin-lay + S: A442 OK XPIG-LATIN ompleted-cay + +7. Server Responses + + Server responses are in three forms: status responses, server data, + and command continuation request. The information contained in a + server response, identified by "Contents:" in the response + descriptions below, is described by function, not by syntax. The + precise syntax of server responses is described in the Formal Syntax + section. + + The client MUST be prepared to accept any response at all times. + + Status responses can be tagged or untagged. Tagged status responses + indicate the completion result (OK, NO, or BAD status) of a client + command, and have a tag matching the command. + + Some status responses, and all server data, are untagged. An + untagged response is indicated by the token "*" instead of a tag. + Untagged status responses indicate server greeting, or server status + + + +Crispin Standards Track [Page 62] + +RFC 3501 IMAPv4 March 2003 + + + that does not indicate the completion of a command (for example, an + impending system shutdown alert). For historical reasons, untagged + server data responses are also called "unsolicited data", although + strictly speaking, only unilateral server data is truly + "unsolicited". + + Certain server data MUST be recorded by the client when it is + received; this is noted in the description of that data. Such data + conveys critical information which affects the interpretation of all + subsequent commands and responses (e.g., updates reflecting the + creation or destruction of messages). + + Other server data SHOULD be recorded for later reference; if the + client does not need to record the data, or if recording the data has + no obvious purpose (e.g., a SEARCH response when no SEARCH command is + in progress), the data SHOULD be ignored. + + An example of unilateral untagged server data occurs when the IMAP + connection is in the selected state. In the selected state, the + server checks the mailbox for new messages as part of command + execution. Normally, this is part of the execution of every command; + hence, a NOOP command suffices to check for new messages. If new + messages are found, the server sends untagged EXISTS and RECENT + responses reflecting the new size of the mailbox. Server + implementations that offer multiple simultaneous access to the same + mailbox SHOULD also send appropriate unilateral untagged FETCH and + EXPUNGE responses if another agent changes the state of any message + flags or expunges any messages. + + Command continuation request responses use the token "+" instead of a + tag. These responses are sent by the server to indicate acceptance + of an incomplete client command and readiness for the remainder of + the command. + +7.1. Server Responses - Status Responses + + Status responses are OK, NO, BAD, PREAUTH and BYE. OK, NO, and BAD + can be tagged or untagged. PREAUTH and BYE are always untagged. + + Status responses MAY include an OPTIONAL "response code". A response + code consists of data inside square brackets in the form of an atom, + possibly followed by a space and arguments. The response code + contains additional information or status codes for client software + beyond the OK/NO/BAD condition, and are defined when there is a + specific action that a client can take based upon the additional + information. + + + + + +Crispin Standards Track [Page 63] + +RFC 3501 IMAPv4 March 2003 + + + The currently defined response codes are: + + ALERT + + The human-readable text contains a special alert that MUST be + presented to the user in a fashion that calls the user's + attention to the message. + + BADCHARSET + + Optionally followed by a parenthesized list of charsets. A + SEARCH failed because the given charset is not supported by + this implementation. If the optional list of charsets is + given, this lists the charsets that are supported by this + implementation. + + CAPABILITY + + Followed by a list of capabilities. This can appear in the + initial OK or PREAUTH response to transmit an initial + capabilities list. This makes it unnecessary for a client to + send a separate CAPABILITY command if it recognizes this + response. + + PARSE + + The human-readable text represents an error in parsing the + [RFC-2822] header or [MIME-IMB] headers of a message in the + mailbox. + + PERMANENTFLAGS + + Followed by a parenthesized list of flags, indicates which of + the known flags the client can change permanently. Any flags + that are in the FLAGS untagged response, but not the + PERMANENTFLAGS list, can not be set permanently. If the client + attempts to STORE a flag that is not in the PERMANENTFLAGS + list, the server will either ignore the change or store the + state change for the remainder of the current session only. + The PERMANENTFLAGS list can also include the special flag \*, + which indicates that it is possible to create new keywords by + attempting to store those flags in the mailbox. + + + + + + + + + +Crispin Standards Track [Page 64] + +RFC 3501 IMAPv4 March 2003 + + + READ-ONLY + + The mailbox is selected read-only, or its access while selected + has changed from read-write to read-only. + + READ-WRITE + + The mailbox is selected read-write, or its access while + selected has changed from read-only to read-write. + + TRYCREATE + + An APPEND or COPY attempt is failing because the target mailbox + does not exist (as opposed to some other reason). This is a + hint to the client that the operation can succeed if the + mailbox is first created by the CREATE command. + + UIDNEXT + + Followed by a decimal number, indicates the next unique + identifier value. Refer to section 2.3.1.1 for more + information. + + UIDVALIDITY + + Followed by a decimal number, indicates the unique identifier + validity value. Refer to section 2.3.1.1 for more information. + + UNSEEN + + Followed by a decimal number, indicates the number of the first + message without the \Seen flag set. + + Additional response codes defined by particular client or server + implementations SHOULD be prefixed with an "X" until they are + added to a revision of this protocol. Client implementations + SHOULD ignore response codes that they do not recognize. + +7.1.1. OK Response + + Contents: OPTIONAL response code + human-readable text + + The OK response indicates an information message from the server. + When tagged, it indicates successful completion of the associated + command. The human-readable text MAY be presented to the user as + an information message. The untagged form indicates an + + + + +Crispin Standards Track [Page 65] + +RFC 3501 IMAPv4 March 2003 + + + information-only message; the nature of the information MAY be + indicated by a response code. + + The untagged form is also used as one of three possible greetings + at connection startup. It indicates that the connection is not + yet authenticated and that a LOGIN command is needed. + + Example: S: * OK IMAP4rev1 server ready + C: A001 LOGIN fred blurdybloop + S: * OK [ALERT] System shutdown in 10 minutes + S: A001 OK LOGIN Completed + + +7.1.2. NO Response + + Contents: OPTIONAL response code + human-readable text + + The NO response indicates an operational error message from the + server. When tagged, it indicates unsuccessful completion of the + associated command. The untagged form indicates a warning; the + command can still complete successfully. The human-readable text + describes the condition. + + Example: C: A222 COPY 1:2 owatagusiam + S: * NO Disk is 98% full, please delete unnecessary data + S: A222 OK COPY completed + C: A223 COPY 3:200 blurdybloop + S: * NO Disk is 98% full, please delete unnecessary data + S: * NO Disk is 99% full, please delete unnecessary data + S: A223 NO COPY failed: disk is full + + +7.1.3. BAD Response + + Contents: OPTIONAL response code + human-readable text + + The BAD response indicates an error message from the server. When + tagged, it reports a protocol-level error in the client's command; + the tag indicates the command that caused the error. The untagged + form indicates a protocol-level error for which the associated + command can not be determined; it can also indicate an internal + server failure. The human-readable text describes the condition. + + + + + + + +Crispin Standards Track [Page 66] + +RFC 3501 IMAPv4 March 2003 + + + Example: C: ...very long command line... + S: * BAD Command line too long + C: ...empty line... + S: * BAD Empty command line + C: A443 EXPUNGE + S: * BAD Disk crash, attempting salvage to a new disk! + S: * OK Salvage successful, no data lost + S: A443 OK Expunge completed + + +7.1.4. PREAUTH Response + + Contents: OPTIONAL response code + human-readable text + + The PREAUTH response is always untagged, and is one of three + possible greetings at connection startup. It indicates that the + connection has already been authenticated by external means; thus + no LOGIN command is needed. + + Example: S: * PREAUTH IMAP4rev1 server logged in as Smith + + +7.1.5. BYE Response + + Contents: OPTIONAL response code + human-readable text + + The BYE response is always untagged, and indicates that the server + is about to close the connection. The human-readable text MAY be + displayed to the user in a status report by the client. The BYE + response is sent under one of four conditions: + + 1) as part of a normal logout sequence. The server will close + the connection after sending the tagged OK response to the + LOGOUT command. + + 2) as a panic shutdown announcement. The server closes the + connection immediately. + + 3) as an announcement of an inactivity autologout. The server + closes the connection immediately. + + 4) as one of three possible greetings at connection startup, + indicating that the server is not willing to accept a + connection from this client. The server closes the + connection immediately. + + + + +Crispin Standards Track [Page 67] + +RFC 3501 IMAPv4 March 2003 + + + The difference between a BYE that occurs as part of a normal + LOGOUT sequence (the first case) and a BYE that occurs because of + a failure (the other three cases) is that the connection closes + immediately in the failure case. In all cases the client SHOULD + continue to read response data from the server until the + connection is closed; this will ensure that any pending untagged + or completion responses are read and processed. + + Example: S: * BYE Autologout; idle for too long + +7.2. Server Responses - Server and Mailbox Status + + These responses are always untagged. This is how server and mailbox + status data are transmitted from the server to the client. Many of + these responses typically result from a command with the same name. + +7.2.1. CAPABILITY Response + + Contents: capability listing + + The CAPABILITY response occurs as a result of a CAPABILITY + command. The capability listing contains a space-separated + listing of capability names that the server supports. The + capability listing MUST include the atom "IMAP4rev1". + + In addition, client and server implementations MUST implement the + STARTTLS, LOGINDISABLED, and AUTH=PLAIN (described in [IMAP-TLS]) + capabilities. See the Security Considerations section for + important information. + + A capability name which begins with "AUTH=" indicates that the + server supports that particular authentication mechanism. + + The LOGINDISABLED capability indicates that the LOGIN command is + disabled, and that the server will respond with a tagged NO + response to any attempt to use the LOGIN command even if the user + name and password are valid. An IMAP client MUST NOT issue the + LOGIN command if the server advertises the LOGINDISABLED + capability. + + Other capability names indicate that the server supports an + extension, revision, or amendment to the IMAP4rev1 protocol. + Server responses MUST conform to this document until the client + issues a command that uses the associated capability. + + Capability names MUST either begin with "X" or be standard or + standards-track IMAP4rev1 extensions, revisions, or amendments + registered with IANA. A server MUST NOT offer unregistered or + + + +Crispin Standards Track [Page 68] + +RFC 3501 IMAPv4 March 2003 + + + non-standard capability names, unless such names are prefixed with + an "X". + + Client implementations SHOULD NOT require any capability name + other than "IMAP4rev1", and MUST ignore any unknown capability + names. + + A server MAY send capabilities automatically, by using the + CAPABILITY response code in the initial PREAUTH or OK responses, + and by sending an updated CAPABILITY response code in the tagged + OK response as part of a successful authentication. It is + unnecessary for a client to send a separate CAPABILITY command if + it recognizes these automatic capabilities. + + Example: S: * CAPABILITY IMAP4rev1 STARTTLS AUTH=GSSAPI XPIG-LATIN + + +7.2.2. LIST Response + + Contents: name attributes + hierarchy delimiter + name + + The LIST response occurs as a result of a LIST command. It + returns a single name that matches the LIST specification. There + can be multiple LIST responses for a single LIST command. + + Four name attributes are defined: + + \Noinferiors + It is not possible for any child levels of hierarchy to exist + under this name; no child levels exist now and none can be + created in the future. + + \Noselect + It is not possible to use this name as a selectable mailbox. + + \Marked + The mailbox has been marked "interesting" by the server; the + mailbox probably contains messages that have been added since + the last time the mailbox was selected. + + \Unmarked + The mailbox does not contain any additional messages since the + last time the mailbox was selected. + + + + + + +Crispin Standards Track [Page 69] + +RFC 3501 IMAPv4 March 2003 + + + If it is not feasible for the server to determine whether or not + the mailbox is "interesting", or if the name is a \Noselect name, + the server SHOULD NOT send either \Marked or \Unmarked. + + The hierarchy delimiter is a character used to delimit levels of + hierarchy in a mailbox name. A client can use it to create child + mailboxes, and to search higher or lower levels of naming + hierarchy. All children of a top-level hierarchy node MUST use + the same separator character. A NIL hierarchy delimiter means + that no hierarchy exists; the name is a "flat" name. + + The name represents an unambiguous left-to-right hierarchy, and + MUST be valid for use as a reference in LIST and LSUB commands. + Unless \Noselect is indicated, the name MUST also be valid as an + argument for commands, such as SELECT, that accept mailbox names. + + Example: S: * LIST (\Noselect) "/" ~/Mail/foo + + +7.2.3. LSUB Response + + Contents: name attributes + hierarchy delimiter + name + + The LSUB response occurs as a result of an LSUB command. It + returns a single name that matches the LSUB specification. There + can be multiple LSUB responses for a single LSUB command. The + data is identical in format to the LIST response. + + Example: S: * LSUB () "." #news.comp.mail.misc + + +7.2.4 STATUS Response + + Contents: name + status parenthesized list + + The STATUS response occurs as a result of an STATUS command. It + returns the mailbox name that matches the STATUS specification and + the requested mailbox status information. + + Example: S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292) + + + + + + + + +Crispin Standards Track [Page 70] + +RFC 3501 IMAPv4 March 2003 + + +7.2.5. SEARCH Response + + Contents: zero or more numbers + + The SEARCH response occurs as a result of a SEARCH or UID SEARCH + command. The number(s) refer to those messages that match the + search criteria. For SEARCH, these are message sequence numbers; + for UID SEARCH, these are unique identifiers. Each number is + delimited by a space. + + Example: S: * SEARCH 2 3 6 + + +7.2.6. FLAGS Response + + Contents: flag parenthesized list + + The FLAGS response occurs as a result of a SELECT or EXAMINE + command. The flag parenthesized list identifies the flags (at a + minimum, the system-defined flags) that are applicable for this + mailbox. Flags other than the system flags can also exist, + depending on server implementation. + + The update from the FLAGS response MUST be recorded by the client. + + Example: S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) + + +7.3. Server Responses - Mailbox Size + + These responses are always untagged. This is how changes in the size + of the mailbox are transmitted from the server to the client. + Immediately following the "*" token is a number that represents a + message count. + +7.3.1. EXISTS Response + + Contents: none + + The EXISTS response reports the number of messages in the mailbox. + This response occurs as a result of a SELECT or EXAMINE command, + and if the size of the mailbox changes (e.g., new messages). + + The update from the EXISTS response MUST be recorded by the + client. + + Example: S: * 23 EXISTS + + + + +Crispin Standards Track [Page 71] + +RFC 3501 IMAPv4 March 2003 + + +7.3.2. RECENT Response + + Contents: none + + The RECENT response reports the number of messages with the + \Recent flag set. This response occurs as a result of a SELECT or + EXAMINE command, and if the size of the mailbox changes (e.g., new + messages). + + Note: It is not guaranteed that the message sequence + numbers of recent messages will be a contiguous range of + the highest n messages in the mailbox (where n is the + value reported by the RECENT response). Examples of + situations in which this is not the case are: multiple + clients having the same mailbox open (the first session + to be notified will see it as recent, others will + probably see it as non-recent), and when the mailbox is + re-ordered by a non-IMAP agent. + + The only reliable way to identify recent messages is to + look at message flags to see which have the \Recent flag + set, or to do a SEARCH RECENT. + + The update from the RECENT response MUST be recorded by the + client. + + Example: S: * 5 RECENT + + +7.4. Server Responses - Message Status + + These responses are always untagged. This is how message data are + transmitted from the server to the client, often as a result of a + command with the same name. Immediately following the "*" token is a + number that represents a message sequence number. + +7.4.1. EXPUNGE Response + + Contents: none + + The EXPUNGE response reports that the specified message sequence + number has been permanently removed from the mailbox. The message + sequence number for each successive message in the mailbox is + immediately decremented by 1, and this decrement is reflected in + message sequence numbers in subsequent responses (including other + untagged EXPUNGE responses). + + + + + +Crispin Standards Track [Page 72] + +RFC 3501 IMAPv4 March 2003 + + + The EXPUNGE response also decrements the number of messages in the + mailbox; it is not necessary to send an EXISTS response with the + new value. + + As a result of the immediate decrement rule, message sequence + numbers that appear in a set of successive EXPUNGE responses + depend upon whether the messages are removed starting from lower + numbers to higher numbers, or from higher numbers to lower + numbers. For example, if the last 5 messages in a 9-message + mailbox are expunged, a "lower to higher" server will send five + untagged EXPUNGE responses for message sequence number 5, whereas + a "higher to lower server" will send successive untagged EXPUNGE + responses for message sequence numbers 9, 8, 7, 6, and 5. + + An EXPUNGE response MUST NOT be sent when no command is in + progress, nor while responding to a FETCH, STORE, or SEARCH + command. This rule is necessary to prevent a loss of + synchronization of message sequence numbers between client and + server. A command is not "in progress" until the complete command + has been received; in particular, a command is not "in progress" + during the negotiation of command continuation. + + Note: UID FETCH, UID STORE, and UID SEARCH are different + commands from FETCH, STORE, and SEARCH. An EXPUNGE + response MAY be sent during a UID command. + + The update from the EXPUNGE response MUST be recorded by the + client. + + Example: S: * 44 EXPUNGE + + +7.4.2. FETCH Response + + Contents: message data + + The FETCH response returns data about a message to the client. + The data are pairs of data item names and their values in + parentheses. This response occurs as the result of a FETCH or + STORE command, as well as by unilateral server decision (e.g., + flag updates). + + The current data items are: + + BODY + A form of BODYSTRUCTURE without extension data. + + + + + +Crispin Standards Track [Page 73] + +RFC 3501 IMAPv4 March 2003 + + + BODY[<section>]<<origin octet>> + A string expressing the body contents of the specified section. + The string SHOULD be interpreted by the client according to the + content transfer encoding, body type, and subtype. + + If the origin octet is specified, this string is a substring of + the entire body contents, starting at that origin octet. This + means that BODY[]<0> MAY be truncated, but BODY[] is NEVER + truncated. + + Note: The origin octet facility MUST NOT be used by a server + in a FETCH response unless the client specifically requested + it by means of a FETCH of a BODY[<section>]<<partial>> data + item. + + 8-bit textual data is permitted if a [CHARSET] identifier is + part of the body parameter parenthesized list for this section. + Note that headers (part specifiers HEADER or MIME, or the + header portion of a MESSAGE/RFC822 part), MUST be 7-bit; 8-bit + characters are not permitted in headers. Note also that the + [RFC-2822] delimiting blank line between the header and the + body is not affected by header line subsetting; the blank line + is always included as part of header data, except in the case + of a message which has no body and no blank line. + + Non-textual data such as binary data MUST be transfer encoded + into a textual form, such as BASE64, prior to being sent to the + client. To derive the original binary data, the client MUST + decode the transfer encoded string. + + BODYSTRUCTURE + A parenthesized list that describes the [MIME-IMB] body + structure of a message. This is computed by the server by + parsing the [MIME-IMB] header fields, defaulting various fields + as necessary. + + For example, a simple text message of 48 lines and 2279 octets + can have a body structure of: ("TEXT" "PLAIN" ("CHARSET" + "US-ASCII") NIL NIL "7BIT" 2279 48) + + Multiple parts are indicated by parenthesis nesting. Instead + of a body type as the first element of the parenthesized list, + there is a sequence of one or more nested body structures. The + second element of the parenthesized list is the multipart + subtype (mixed, digest, parallel, alternative, etc.). + + + + + + +Crispin Standards Track [Page 74] + +RFC 3501 IMAPv4 March 2003 + + + For example, a two part message consisting of a text and a + BASE64-encoded text attachment can have a body structure of: + (("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152 + 23)("TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME" "cc.diff") + "<960723163407.20117h@cac.washington.edu>" "Compiler diff" + "BASE64" 4554 73) "MIXED") + + Extension data follows the multipart subtype. Extension data + is never returned with the BODY fetch, but can be returned with + a BODYSTRUCTURE fetch. Extension data, if present, MUST be in + the defined order. The extension data of a multipart body part + are in the following order: + + body parameter parenthesized list + A parenthesized list of attribute/value pairs [e.g., ("foo" + "bar" "baz" "rag") where "bar" is the value of "foo", and + "rag" is the value of "baz"] as defined in [MIME-IMB]. + + body disposition + A parenthesized list, consisting of a disposition type + string, followed by a parenthesized list of disposition + attribute/value pairs as defined in [DISPOSITION]. + + body language + A string or parenthesized list giving the body language + value as defined in [LANGUAGE-TAGS]. + + body location + A string list giving the body content URI as defined in + [LOCATION]. + + Any following extension data are not yet defined in this + version of the protocol. Such extension data can consist of + zero or more NILs, strings, numbers, or potentially nested + parenthesized lists of such data. Client implementations that + do a BODYSTRUCTURE fetch MUST be prepared to accept such + extension data. Server implementations MUST NOT send such + extension data until it has been defined by a revision of this + protocol. + + The basic fields of a non-multipart body part are in the + following order: + + body type + A string giving the content media type name as defined in + [MIME-IMB]. + + + + + +Crispin Standards Track [Page 75] + +RFC 3501 IMAPv4 March 2003 + + + body subtype + A string giving the content subtype name as defined in + [MIME-IMB]. + + body parameter parenthesized list + A parenthesized list of attribute/value pairs [e.g., ("foo" + "bar" "baz" "rag") where "bar" is the value of "foo" and + "rag" is the value of "baz"] as defined in [MIME-IMB]. + + body id + A string giving the content id as defined in [MIME-IMB]. + + body description + A string giving the content description as defined in + [MIME-IMB]. + + body encoding + A string giving the content transfer encoding as defined in + [MIME-IMB]. + + body size + A number giving the size of the body in octets. Note that + this size is the size in its transfer encoding and not the + resulting size after any decoding. + + A body type of type MESSAGE and subtype RFC822 contains, + immediately after the basic fields, the envelope structure, + body structure, and size in text lines of the encapsulated + message. + + A body type of type TEXT contains, immediately after the basic + fields, the size of the body in text lines. Note that this + size is the size in its content transfer encoding and not the + resulting size after any decoding. + + Extension data follows the basic fields and the type-specific + fields listed above. Extension data is never returned with the + BODY fetch, but can be returned with a BODYSTRUCTURE fetch. + Extension data, if present, MUST be in the defined order. + + The extension data of a non-multipart body part are in the + following order: + + body MD5 + A string giving the body MD5 value as defined in [MD5]. + + + + + + +Crispin Standards Track [Page 76] + +RFC 3501 IMAPv4 March 2003 + + + body disposition + A parenthesized list with the same content and function as + the body disposition for a multipart body part. + + body language + A string or parenthesized list giving the body language + value as defined in [LANGUAGE-TAGS]. + + body location + A string list giving the body content URI as defined in + [LOCATION]. + + Any following extension data are not yet defined in this + version of the protocol, and would be as described above under + multipart extension data. + + ENVELOPE + A parenthesized list that describes the envelope structure of a + message. This is computed by the server by parsing the + [RFC-2822] header into the component parts, defaulting various + fields as necessary. + + The fields of the envelope structure are in the following + order: date, subject, from, sender, reply-to, to, cc, bcc, + in-reply-to, and message-id. The date, subject, in-reply-to, + and message-id fields are strings. The from, sender, reply-to, + to, cc, and bcc fields are parenthesized lists of address + structures. + + An address structure is a parenthesized list that describes an + electronic mail address. The fields of an address structure + are in the following order: personal name, [SMTP] + at-domain-list (source route), mailbox name, and host name. + + [RFC-2822] group syntax is indicated by a special form of + address structure in which the host name field is NIL. If the + mailbox name field is also NIL, this is an end of group marker + (semi-colon in RFC 822 syntax). If the mailbox name field is + non-NIL, this is a start of group marker, and the mailbox name + field holds the group name phrase. + + If the Date, Subject, In-Reply-To, and Message-ID header lines + are absent in the [RFC-2822] header, the corresponding member + of the envelope is NIL; if these header lines are present but + empty the corresponding member of the envelope is the empty + string. + + + + + +Crispin Standards Track [Page 77] + +RFC 3501 IMAPv4 March 2003 + + + Note: some servers may return a NIL envelope member in the + "present but empty" case. Clients SHOULD treat NIL and + empty string as identical. + + Note: [RFC-2822] requires that all messages have a valid + Date header. Therefore, the date member in the envelope can + not be NIL or the empty string. + + Note: [RFC-2822] requires that the In-Reply-To and + Message-ID headers, if present, have non-empty content. + Therefore, the in-reply-to and message-id members in the + envelope can not be the empty string. + + If the From, To, cc, and bcc header lines are absent in the + [RFC-2822] header, or are present but empty, the corresponding + member of the envelope is NIL. + + If the Sender or Reply-To lines are absent in the [RFC-2822] + header, or are present but empty, the server sets the + corresponding member of the envelope to be the same value as + the from member (the client is not expected to know to do + this). + + Note: [RFC-2822] requires that all messages have a valid + From header. Therefore, the from, sender, and reply-to + members in the envelope can not be NIL. + + FLAGS + A parenthesized list of flags that are set for this message. + + INTERNALDATE + A string representing the internal date of the message. + + RFC822 + Equivalent to BODY[]. + + RFC822.HEADER + Equivalent to BODY[HEADER]. Note that this did not result in + \Seen being set, because RFC822.HEADER response data occurs as + a result of a FETCH of RFC822.HEADER. BODY[HEADER] response + data occurs as a result of a FETCH of BODY[HEADER] (which sets + \Seen) or BODY.PEEK[HEADER] (which does not set \Seen). + + RFC822.SIZE + A number expressing the [RFC-2822] size of the message. + + + + + + +Crispin Standards Track [Page 78] + +RFC 3501 IMAPv4 March 2003 + + + RFC822.TEXT + Equivalent to BODY[TEXT]. + + UID + A number expressing the unique identifier of the message. + + + Example: S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827) + + +7.5. Server Responses - Command Continuation Request + + The command continuation request response is indicated by a "+" token + instead of a tag. This form of response indicates that the server is + ready to accept the continuation of a command from the client. The + remainder of this response is a line of text. + + This response is used in the AUTHENTICATE command to transmit server + data to the client, and request additional client data. This + response is also used if an argument to any command is a literal. + + The client is not permitted to send the octets of the literal unless + the server indicates that it is expected. This permits the server to + process commands and reject errors on a line-by-line basis. The + remainder of the command, including the CRLF that terminates a + command, follows the octets of the literal. If there are any + additional command arguments, the literal octets are followed by a + space and those arguments. + + Example: C: A001 LOGIN {11} + S: + Ready for additional command text + C: FRED FOOBAR {7} + S: + Ready for additional command text + C: fat man + S: A001 OK LOGIN completed + C: A044 BLURDYBLOOP {102856} + S: A044 BAD No such command as "BLURDYBLOOP" + + + + + + + + + + + + + + +Crispin Standards Track [Page 79] + +RFC 3501 IMAPv4 March 2003 + + +8. Sample IMAP4rev1 connection + + The following is a transcript of an IMAP4rev1 connection. A long + line in this sample is broken for editorial clarity. + +S: * OK IMAP4rev1 Service Ready +C: a001 login mrc secret +S: a001 OK LOGIN completed +C: a002 select inbox +S: * 18 EXISTS +S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) +S: * 2 RECENT +S: * OK [UNSEEN 17] Message 17 is the first unseen message +S: * OK [UIDVALIDITY 3857529045] UIDs valid +S: a002 OK [READ-WRITE] SELECT completed +C: a003 fetch 12 full +S: * 12 FETCH (FLAGS (\Seen) INTERNALDATE "17-Jul-1996 02:44:25 -0700" + RFC822.SIZE 4286 ENVELOPE ("Wed, 17 Jul 1996 02:23:25 -0700 (PDT)" + "IMAP4rev1 WG mtg summary and minutes" + (("Terry Gray" NIL "gray" "cac.washington.edu")) + (("Terry Gray" NIL "gray" "cac.washington.edu")) + (("Terry Gray" NIL "gray" "cac.washington.edu")) + ((NIL NIL "imap" "cac.washington.edu")) + ((NIL NIL "minutes" "CNRI.Reston.VA.US") + ("John Klensin" NIL "KLENSIN" "MIT.EDU")) NIL NIL + "<B27397-0100000@cac.washington.edu>") + BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 3028 + 92)) +S: a003 OK FETCH completed +C: a004 fetch 12 body[header] +S: * 12 FETCH (BODY[HEADER] {342} +S: Date: Wed, 17 Jul 1996 02:23:25 -0700 (PDT) +S: From: Terry Gray <gray@cac.washington.edu> +S: Subject: IMAP4rev1 WG mtg summary and minutes +S: To: imap@cac.washington.edu +S: cc: minutes@CNRI.Reston.VA.US, John Klensin <KLENSIN@MIT.EDU> +S: Message-Id: <B27397-0100000@cac.washington.edu> +S: MIME-Version: 1.0 +S: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII +S: +S: ) +S: a004 OK FETCH completed +C: a005 store 12 +flags \deleted +S: * 12 FETCH (FLAGS (\Seen \Deleted)) +S: a005 OK +FLAGS completed +C: a006 logout +S: * BYE IMAP4rev1 server terminating connection +S: a006 OK LOGOUT completed + + + +Crispin Standards Track [Page 80] + +RFC 3501 IMAPv4 March 2003 + + +9. Formal Syntax + + The following syntax specification uses the Augmented Backus-Naur + Form (ABNF) notation as specified in [ABNF]. + + In the case of alternative or optional rules in which a later rule + overlaps an earlier rule, the rule which is listed earlier MUST take + priority. For example, "\Seen" when parsed as a flag is the \Seen + flag name and not a flag-extension, even though "\Seen" can be parsed + as a flag-extension. Some, but not all, instances of this rule are + noted below. + + Note: [ABNF] rules MUST be followed strictly; in + particular: + + (1) Except as noted otherwise, all alphabetic characters + are case-insensitive. The use of upper or lower case + characters to define token strings is for editorial clarity + only. Implementations MUST accept these strings in a + case-insensitive fashion. + + (2) In all cases, SP refers to exactly one space. It is + NOT permitted to substitute TAB, insert additional spaces, + or otherwise treat SP as being equivalent to LWSP. + + (3) The ASCII NUL character, %x00, MUST NOT be used at any + time. + +address = "(" addr-name SP addr-adl SP addr-mailbox SP + addr-host ")" + +addr-adl = nstring + ; Holds route from [RFC-2822] route-addr if + ; non-NIL + +addr-host = nstring + ; NIL indicates [RFC-2822] group syntax. + ; Otherwise, holds [RFC-2822] domain name + +addr-mailbox = nstring + ; NIL indicates end of [RFC-2822] group; if + ; non-NIL and addr-host is NIL, holds + ; [RFC-2822] group name. + ; Otherwise, holds [RFC-2822] local-part + ; after removing [RFC-2822] quoting + + + + + + +Crispin Standards Track [Page 81] + +RFC 3501 IMAPv4 March 2003 + + +addr-name = nstring + ; If non-NIL, holds phrase from [RFC-2822] + ; mailbox after removing [RFC-2822] quoting + +append = "APPEND" SP mailbox [SP flag-list] [SP date-time] SP + literal + +astring = 1*ASTRING-CHAR / string + +ASTRING-CHAR = ATOM-CHAR / resp-specials + +atom = 1*ATOM-CHAR + +ATOM-CHAR = <any CHAR except atom-specials> + +atom-specials = "(" / ")" / "{" / SP / CTL / list-wildcards / + quoted-specials / resp-specials + +authenticate = "AUTHENTICATE" SP auth-type *(CRLF base64) + +auth-type = atom + ; Defined by [SASL] + +base64 = *(4base64-char) [base64-terminal] + +base64-char = ALPHA / DIGIT / "+" / "/" + ; Case-sensitive + +base64-terminal = (2base64-char "==") / (3base64-char "=") + +body = "(" (body-type-1part / body-type-mpart) ")" + +body-extension = nstring / number / + "(" body-extension *(SP body-extension) ")" + ; Future expansion. Client implementations + ; MUST accept body-extension fields. Server + ; implementations MUST NOT generate + ; body-extension fields except as defined by + ; future standard or standards-track + ; revisions of this specification. + +body-ext-1part = body-fld-md5 [SP body-fld-dsp [SP body-fld-lang + [SP body-fld-loc *(SP body-extension)]]] + ; MUST NOT be returned on non-extensible + ; "BODY" fetch + + + + + + +Crispin Standards Track [Page 82] + +RFC 3501 IMAPv4 March 2003 + + +body-ext-mpart = body-fld-param [SP body-fld-dsp [SP body-fld-lang + [SP body-fld-loc *(SP body-extension)]]] + ; MUST NOT be returned on non-extensible + ; "BODY" fetch + +body-fields = body-fld-param SP body-fld-id SP body-fld-desc SP + body-fld-enc SP body-fld-octets + +body-fld-desc = nstring + +body-fld-dsp = "(" string SP body-fld-param ")" / nil + +body-fld-enc = (DQUOTE ("7BIT" / "8BIT" / "BINARY" / "BASE64"/ + "QUOTED-PRINTABLE") DQUOTE) / string + +body-fld-id = nstring + +body-fld-lang = nstring / "(" string *(SP string) ")" + +body-fld-loc = nstring + +body-fld-lines = number + +body-fld-md5 = nstring + +body-fld-octets = number + +body-fld-param = "(" string SP string *(SP string SP string) ")" / nil + +body-type-1part = (body-type-basic / body-type-msg / body-type-text) + [SP body-ext-1part] + +body-type-basic = media-basic SP body-fields + ; MESSAGE subtype MUST NOT be "RFC822" + +body-type-mpart = 1*body SP media-subtype + [SP body-ext-mpart] + +body-type-msg = media-message SP body-fields SP envelope + SP body SP body-fld-lines + +body-type-text = media-text SP body-fields SP body-fld-lines + +capability = ("AUTH=" auth-type) / atom + ; New capabilities MUST begin with "X" or be + ; registered with IANA as standard or + ; standards-track + + + + +Crispin Standards Track [Page 83] + +RFC 3501 IMAPv4 March 2003 + + +capability-data = "CAPABILITY" *(SP capability) SP "IMAP4rev1" + *(SP capability) + ; Servers MUST implement the STARTTLS, AUTH=PLAIN, + ; and LOGINDISABLED capabilities + ; Servers which offer RFC 1730 compatibility MUST + ; list "IMAP4" as the first capability. + +CHAR8 = %x01-ff + ; any OCTET except NUL, %x00 + +command = tag SP (command-any / command-auth / command-nonauth / + command-select) CRLF + ; Modal based on state + +command-any = "CAPABILITY" / "LOGOUT" / "NOOP" / x-command + ; Valid in all states + +command-auth = append / create / delete / examine / list / lsub / + rename / select / status / subscribe / unsubscribe + ; Valid only in Authenticated or Selected state + +command-nonauth = login / authenticate / "STARTTLS" + ; Valid only when in Not Authenticated state + +command-select = "CHECK" / "CLOSE" / "EXPUNGE" / copy / fetch / store / + uid / search + ; Valid only when in Selected state + +continue-req = "+" SP (resp-text / base64) CRLF + +copy = "COPY" SP sequence-set SP mailbox + +create = "CREATE" SP mailbox + ; Use of INBOX gives a NO error + +date = date-text / DQUOTE date-text DQUOTE + +date-day = 1*2DIGIT + ; Day of month + +date-day-fixed = (SP DIGIT) / 2DIGIT + ; Fixed-format version of date-day + +date-month = "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" / + "Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec" + +date-text = date-day "-" date-month "-" date-year + + + + +Crispin Standards Track [Page 84] + +RFC 3501 IMAPv4 March 2003 + + +date-year = 4DIGIT + +date-time = DQUOTE date-day-fixed "-" date-month "-" date-year + SP time SP zone DQUOTE + +delete = "DELETE" SP mailbox + ; Use of INBOX gives a NO error + +digit-nz = %x31-39 + ; 1-9 + +envelope = "(" env-date SP env-subject SP env-from SP + env-sender SP env-reply-to SP env-to SP env-cc SP + env-bcc SP env-in-reply-to SP env-message-id ")" + +env-bcc = "(" 1*address ")" / nil + +env-cc = "(" 1*address ")" / nil + +env-date = nstring + +env-from = "(" 1*address ")" / nil + +env-in-reply-to = nstring + +env-message-id = nstring + +env-reply-to = "(" 1*address ")" / nil + +env-sender = "(" 1*address ")" / nil + +env-subject = nstring + +env-to = "(" 1*address ")" / nil + +examine = "EXAMINE" SP mailbox + +fetch = "FETCH" SP sequence-set SP ("ALL" / "FULL" / "FAST" / + fetch-att / "(" fetch-att *(SP fetch-att) ")") + +fetch-att = "ENVELOPE" / "FLAGS" / "INTERNALDATE" / + "RFC822" [".HEADER" / ".SIZE" / ".TEXT"] / + "BODY" ["STRUCTURE"] / "UID" / + "BODY" section ["<" number "." nz-number ">"] / + "BODY.PEEK" section ["<" number "." nz-number ">"] + + + + + + +Crispin Standards Track [Page 85] + +RFC 3501 IMAPv4 March 2003 + + +flag = "\Answered" / "\Flagged" / "\Deleted" / + "\Seen" / "\Draft" / flag-keyword / flag-extension + ; Does not include "\Recent" + +flag-extension = "\" atom + ; Future expansion. Client implementations + ; MUST accept flag-extension flags. Server + ; implementations MUST NOT generate + ; flag-extension flags except as defined by + ; future standard or standards-track + ; revisions of this specification. + +flag-fetch = flag / "\Recent" + +flag-keyword = atom + +flag-list = "(" [flag *(SP flag)] ")" + +flag-perm = flag / "\*" + +greeting = "*" SP (resp-cond-auth / resp-cond-bye) CRLF + +header-fld-name = astring + +header-list = "(" header-fld-name *(SP header-fld-name) ")" + +list = "LIST" SP mailbox SP list-mailbox + +list-mailbox = 1*list-char / string + +list-char = ATOM-CHAR / list-wildcards / resp-specials + +list-wildcards = "%" / "*" + +literal = "{" number "}" CRLF *CHAR8 + ; Number represents the number of CHAR8s + +login = "LOGIN" SP userid SP password + +lsub = "LSUB" SP mailbox SP list-mailbox + + + + + + + + + + + +Crispin Standards Track [Page 86] + +RFC 3501 IMAPv4 March 2003 + + +mailbox = "INBOX" / astring + ; INBOX is case-insensitive. All case variants of + ; INBOX (e.g., "iNbOx") MUST be interpreted as INBOX + ; not as an astring. An astring which consists of + ; the case-insensitive sequence "I" "N" "B" "O" "X" + ; is considered to be INBOX and not an astring. + ; Refer to section 5.1 for further + ; semantic details of mailbox names. + +mailbox-data = "FLAGS" SP flag-list / "LIST" SP mailbox-list / + "LSUB" SP mailbox-list / "SEARCH" *(SP nz-number) / + "STATUS" SP mailbox SP "(" [status-att-list] ")" / + number SP "EXISTS" / number SP "RECENT" + +mailbox-list = "(" [mbx-list-flags] ")" SP + (DQUOTE QUOTED-CHAR DQUOTE / nil) SP mailbox + +mbx-list-flags = *(mbx-list-oflag SP) mbx-list-sflag + *(SP mbx-list-oflag) / + mbx-list-oflag *(SP mbx-list-oflag) + +mbx-list-oflag = "\Noinferiors" / flag-extension + ; Other flags; multiple possible per LIST response + +mbx-list-sflag = "\Noselect" / "\Marked" / "\Unmarked" + ; Selectability flags; only one per LIST response + +media-basic = ((DQUOTE ("APPLICATION" / "AUDIO" / "IMAGE" / + "MESSAGE" / "VIDEO") DQUOTE) / string) SP + media-subtype + ; Defined in [MIME-IMT] + +media-message = DQUOTE "MESSAGE" DQUOTE SP DQUOTE "RFC822" DQUOTE + ; Defined in [MIME-IMT] + +media-subtype = string + ; Defined in [MIME-IMT] + +media-text = DQUOTE "TEXT" DQUOTE SP media-subtype + ; Defined in [MIME-IMT] + +message-data = nz-number SP ("EXPUNGE" / ("FETCH" SP msg-att)) + +msg-att = "(" (msg-att-dynamic / msg-att-static) + *(SP (msg-att-dynamic / msg-att-static)) ")" + +msg-att-dynamic = "FLAGS" SP "(" [flag-fetch *(SP flag-fetch)] ")" + ; MAY change for a message + + + +Crispin Standards Track [Page 87] + +RFC 3501 IMAPv4 March 2003 + + +msg-att-static = "ENVELOPE" SP envelope / "INTERNALDATE" SP date-time / + "RFC822" [".HEADER" / ".TEXT"] SP nstring / + "RFC822.SIZE" SP number / + "BODY" ["STRUCTURE"] SP body / + "BODY" section ["<" number ">"] SP nstring / + "UID" SP uniqueid + ; MUST NOT change for a message + +nil = "NIL" + +nstring = string / nil + +number = 1*DIGIT + ; Unsigned 32-bit integer + ; (0 <= n < 4,294,967,296) + +nz-number = digit-nz *DIGIT + ; Non-zero unsigned 32-bit integer + ; (0 < n < 4,294,967,296) + +password = astring + +quoted = DQUOTE *QUOTED-CHAR DQUOTE + +QUOTED-CHAR = <any TEXT-CHAR except quoted-specials> / + "\" quoted-specials + +quoted-specials = DQUOTE / "\" + +rename = "RENAME" SP mailbox SP mailbox + ; Use of INBOX as a destination gives a NO error + +response = *(continue-req / response-data) response-done + +response-data = "*" SP (resp-cond-state / resp-cond-bye / + mailbox-data / message-data / capability-data) CRLF + +response-done = response-tagged / response-fatal + +response-fatal = "*" SP resp-cond-bye CRLF + ; Server closes connection immediately + +response-tagged = tag SP resp-cond-state CRLF + +resp-cond-auth = ("OK" / "PREAUTH") SP resp-text + ; Authentication condition + + + + + +Crispin Standards Track [Page 88] + +RFC 3501 IMAPv4 March 2003 + + +resp-cond-bye = "BYE" SP resp-text + +resp-cond-state = ("OK" / "NO" / "BAD") SP resp-text + ; Status condition + +resp-specials = "]" + +resp-text = ["[" resp-text-code "]" SP] text + +resp-text-code = "ALERT" / + "BADCHARSET" [SP "(" astring *(SP astring) ")" ] / + capability-data / "PARSE" / + "PERMANENTFLAGS" SP "(" + [flag-perm *(SP flag-perm)] ")" / + "READ-ONLY" / "READ-WRITE" / "TRYCREATE" / + "UIDNEXT" SP nz-number / "UIDVALIDITY" SP nz-number / + "UNSEEN" SP nz-number / + atom [SP 1*<any TEXT-CHAR except "]">] + +search = "SEARCH" [SP "CHARSET" SP astring] 1*(SP search-key) + ; CHARSET argument to MUST be registered with IANA + +search-key = "ALL" / "ANSWERED" / "BCC" SP astring / + "BEFORE" SP date / "BODY" SP astring / + "CC" SP astring / "DELETED" / "FLAGGED" / + "FROM" SP astring / "KEYWORD" SP flag-keyword / + "NEW" / "OLD" / "ON" SP date / "RECENT" / "SEEN" / + "SINCE" SP date / "SUBJECT" SP astring / + "TEXT" SP astring / "TO" SP astring / + "UNANSWERED" / "UNDELETED" / "UNFLAGGED" / + "UNKEYWORD" SP flag-keyword / "UNSEEN" / + ; Above this line were in [IMAP2] + "DRAFT" / "HEADER" SP header-fld-name SP astring / + "LARGER" SP number / "NOT" SP search-key / + "OR" SP search-key SP search-key / + "SENTBEFORE" SP date / "SENTON" SP date / + "SENTSINCE" SP date / "SMALLER" SP number / + "UID" SP sequence-set / "UNDRAFT" / sequence-set / + "(" search-key *(SP search-key) ")" + +section = "[" [section-spec] "]" + +section-msgtext = "HEADER" / "HEADER.FIELDS" [".NOT"] SP header-list / + "TEXT" + ; top-level or MESSAGE/RFC822 part + +section-part = nz-number *("." nz-number) + ; body part nesting + + + +Crispin Standards Track [Page 89] + +RFC 3501 IMAPv4 March 2003 + + +section-spec = section-msgtext / (section-part ["." section-text]) + +section-text = section-msgtext / "MIME" + ; text other than actual body part (headers, etc.) + +select = "SELECT" SP mailbox + +seq-number = nz-number / "*" + ; message sequence number (COPY, FETCH, STORE + ; commands) or unique identifier (UID COPY, + ; UID FETCH, UID STORE commands). + ; * represents the largest number in use. In + ; the case of message sequence numbers, it is + ; the number of messages in a non-empty mailbox. + ; In the case of unique identifiers, it is the + ; unique identifier of the last message in the + ; mailbox or, if the mailbox is empty, the + ; mailbox's current UIDNEXT value. + ; The server should respond with a tagged BAD + ; response to a command that uses a message + ; sequence number greater than the number of + ; messages in the selected mailbox. This + ; includes "*" if the selected mailbox is empty. + +seq-range = seq-number ":" seq-number + ; two seq-number values and all values between + ; these two regardless of order. + ; Example: 2:4 and 4:2 are equivalent and indicate + ; values 2, 3, and 4. + ; Example: a unique identifier sequence range of + ; 3291:* includes the UID of the last message in + ; the mailbox, even if that value is less than 3291. + +sequence-set = (seq-number / seq-range) *("," sequence-set) + ; set of seq-number values, regardless of order. + ; Servers MAY coalesce overlaps and/or execute the + ; sequence in any order. + ; Example: a message sequence number set of + ; 2,4:7,9,12:* for a mailbox with 15 messages is + ; equivalent to 2,4,5,6,7,9,12,13,14,15 + ; Example: a message sequence number set of *:4,5:7 + ; for a mailbox with 10 messages is equivalent to + ; 10,9,8,7,6,5,4,5,6,7 and MAY be reordered and + ; overlap coalesced to be 4,5,6,7,8,9,10. + +status = "STATUS" SP mailbox SP + "(" status-att *(SP status-att) ")" + + + + +Crispin Standards Track [Page 90] + +RFC 3501 IMAPv4 March 2003 + + +status-att = "MESSAGES" / "RECENT" / "UIDNEXT" / "UIDVALIDITY" / + "UNSEEN" + +status-att-list = status-att SP number *(SP status-att SP number) + +store = "STORE" SP sequence-set SP store-att-flags + +store-att-flags = (["+" / "-"] "FLAGS" [".SILENT"]) SP + (flag-list / (flag *(SP flag))) + +string = quoted / literal + +subscribe = "SUBSCRIBE" SP mailbox + +tag = 1*<any ASTRING-CHAR except "+"> + +text = 1*TEXT-CHAR + +TEXT-CHAR = <any CHAR except CR and LF> + +time = 2DIGIT ":" 2DIGIT ":" 2DIGIT + ; Hours minutes seconds + +uid = "UID" SP (copy / fetch / search / store) + ; Unique identifiers used instead of message + ; sequence numbers + +uniqueid = nz-number + ; Strictly ascending + +unsubscribe = "UNSUBSCRIBE" SP mailbox + +userid = astring + +x-command = "X" atom <experimental command arguments> + +zone = ("+" / "-") 4DIGIT + ; Signed four-digit value of hhmm representing + ; hours and minutes east of Greenwich (that is, + ; the amount that the given time differs from + ; Universal Time). Subtracting the timezone + ; from the given time will give the UT form. + ; The Universal Time zone is "+0000". + + + + + + + + +Crispin Standards Track [Page 91] + +RFC 3501 IMAPv4 March 2003 + + +10. Author's Note + + This document is a revision or rewrite of earlier documents, and + supercedes the protocol specification in those documents: RFC 2060, + RFC 1730, unpublished IMAP2bis.TXT document, RFC 1176, and RFC 1064. + +11. Security Considerations + + IMAP4rev1 protocol transactions, including electronic mail data, are + sent in the clear over the network unless protection from snooping is + negotiated. This can be accomplished either by the use of STARTTLS, + negotiated privacy protection in the AUTHENTICATE command, or some + other protection mechanism. + +11.1. STARTTLS Security Considerations + + The specification of the STARTTLS command and LOGINDISABLED + capability in this document replaces that in [IMAP-TLS]. [IMAP-TLS] + remains normative for the PLAIN [SASL] authenticator. + + IMAP client and server implementations MUST implement the + TLS_RSA_WITH_RC4_128_MD5 [TLS] cipher suite, and SHOULD implement the + TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA [TLS] cipher suite. This is + important as it assures that any two compliant implementations can be + configured to interoperate. All other cipher suites are OPTIONAL. + Note that this is a change from section 2.1 of [IMAP-TLS]. + + During the [TLS] negotiation, the client MUST check its understanding + of the server hostname against the server's identity as presented in + the server Certificate message, in order to prevent man-in-the-middle + attacks. If the match fails, the client SHOULD either ask for + explicit user confirmation, or terminate the connection and indicate + that the server's identity is suspect. Matching is performed + according to these rules: + + The client MUST use the server hostname it used to open the + connection as the value to compare against the server name + as expressed in the server certificate. The client MUST + NOT use any form of the server hostname derived from an + insecure remote source (e.g., insecure DNS lookup). CNAME + canonicalization is not done. + + If a subjectAltName extension of type dNSName is present in + the certificate, it SHOULD be used as the source of the + server's identity. + + Matching is case-insensitive. + + + + +Crispin Standards Track [Page 92] + +RFC 3501 IMAPv4 March 2003 + + + A "*" wildcard character MAY be used as the left-most name + component in the certificate. For example, *.example.com + would match a.example.com, foo.example.com, etc. but would + not match example.com. + + If the certificate contains multiple names (e.g., more than + one dNSName field), then a match with any one of the fields + is considered acceptable. + + Both the client and server MUST check the result of the STARTTLS + command and subsequent [TLS] negotiation to see whether acceptable + authentication or privacy was achieved. + +11.2. Other Security Considerations + + A server error message for an AUTHENTICATE command which fails due to + invalid credentials SHOULD NOT detail why the credentials are + invalid. + + Use of the LOGIN command sends passwords in the clear. This can be + avoided by using the AUTHENTICATE command with a [SASL] mechanism + that does not use plaintext passwords, by first negotiating + encryption via STARTTLS or some other protection mechanism. + + A server implementation MUST implement a configuration that, at the + time of authentication, requires: + (1) The STARTTLS command has been negotiated. + OR + (2) Some other mechanism that protects the session from password + snooping has been provided. + OR + (3) The following measures are in place: + (a) The LOGINDISABLED capability is advertised, and [SASL] + mechanisms (such as PLAIN) using plaintext passwords are NOT + advertised in the CAPABILITY list. + AND + (b) The LOGIN command returns an error even if the password is + correct. + AND + (c) The AUTHENTICATE command returns an error with all [SASL] + mechanisms that use plaintext passwords, even if the password + is correct. + + A server error message for a failing LOGIN command SHOULD NOT specify + that the user name, as opposed to the password, is invalid. + + A server SHOULD have mechanisms in place to limit or delay failed + AUTHENTICATE/LOGIN attempts. + + + +Crispin Standards Track [Page 93] + +RFC 3501 IMAPv4 March 2003 + + + Additional security considerations are discussed in the section + discussing the AUTHENTICATE and LOGIN commands. + +12. IANA Considerations + + IMAP4 capabilities are registered by publishing a standards track or + IESG approved experimental RFC. The registry is currently located + at: + + http://www.iana.org/assignments/imap4-capabilities + + As this specification revises the STARTTLS and LOGINDISABLED + extensions previously defined in [IMAP-TLS], the registry will be + updated accordingly. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 94] + +RFC 3501 IMAPv4 March 2003 + + +Appendices + +A. Normative References + + The following documents contain definitions or specifications that + are necessary to understand this document properly: + [ABNF] Crocker, D. and P. Overell, "Augmented BNF for + Syntax Specifications: ABNF", RFC 2234, + November 1997. + + [ANONYMOUS] Newman, C., "Anonymous SASL Mechanism", RFC + 2245, November 1997. + + [CHARSET] Freed, N. and J. Postel, "IANA Character Set + Registration Procedures", RFC 2978, October + 2000. + + [DIGEST-MD5] Leach, P. and C. Newman, "Using Digest + Authentication as a SASL Mechanism", RFC 2831, + May 2000. + + [DISPOSITION] Troost, R., Dorner, S. and K. Moore, + "Communicating Presentation Information in + Internet Messages: The Content-Disposition + Header", RFC 2183, August 1997. + + [IMAP-TLS] Newman, C., "Using TLS with IMAP, POP3 and + ACAP", RFC 2595, June 1999. + + [KEYWORDS] Bradner, S., "Key words for use in RFCs to + Indicate Requirement Levels", BCP 14, RFC 2119, + March 1997. + + [LANGUAGE-TAGS] Alvestrand, H., "Tags for the Identification of + Languages", BCP 47, RFC 3066, January 2001. + + [LOCATION] Palme, J., Hopmann, A. and N. Shelness, "MIME + Encapsulation of Aggregate Documents, such as + HTML (MHTML)", RFC 2557, March 1999. + + [MD5] Myers, J. and M. Rose, "The Content-MD5 Header + Field", RFC 1864, October 1995. + + + + + + + + + +Crispin Standards Track [Page 95] + +RFC 3501 IMAPv4 March 2003 + + + [MIME-HDRS] Moore, K., "MIME (Multipurpose Internet Mail + Extensions) Part Three: Message Header + Extensions for Non-ASCII Text", RFC 2047, + November 1996. + + [MIME-IMB] Freed, N. and N. Borenstein, "MIME + (Multipurpose Internet Mail Extensions) Part + One: Format of Internet Message Bodies", RFC + 2045, November 1996. + + [MIME-IMT] Freed, N. and N. Borenstein, "MIME + (Multipurpose Internet Mail Extensions) Part + Two: Media Types", RFC 2046, November 1996. + + [RFC-2822] Resnick, P., "Internet Message Format", RFC + 2822, April 2001. + + [SASL] Myers, J., "Simple Authentication and Security + Layer (SASL)", RFC 2222, October 1997. + + [TLS] Dierks, T. and C. Allen, "The TLS Protocol + Version 1.0", RFC 2246, January 1999. + + [UTF-7] Goldsmith, D. and M. Davis, "UTF-7: A Mail-Safe + Transformation Format of Unicode", RFC 2152, + May 1997. + + The following documents describe quality-of-implementation issues + that should be carefully considered when implementing this protocol: + + [IMAP-IMPLEMENTATION] Leiba, B., "IMAP Implementation + Recommendations", RFC 2683, September 1999. + + [IMAP-MULTIACCESS] Gahrns, M., "IMAP4 Multi-Accessed Mailbox + Practice", RFC 2180, July 1997. + +A.1 Informative References + + The following documents describe related protocols: + + [IMAP-DISC] Austein, R., "Synchronization Operations for + Disconnected IMAP4 Clients", Work in Progress. + + [IMAP-MODEL] Crispin, M., "Distributed Electronic Mail + Models in IMAP4", RFC 1733, December 1994. + + + + + + +Crispin Standards Track [Page 96] + +RFC 3501 IMAPv4 March 2003 + + + [ACAP] Newman, C. and J. Myers, "ACAP -- Application + Configuration Access Protocol", RFC 2244, + November 1997. + + [SMTP] Klensin, J., "Simple Mail Transfer Protocol", + STD 10, RFC 2821, April 2001. + + The following documents are historical or describe historical aspects + of this protocol: + + [IMAP-COMPAT] Crispin, M., "IMAP4 Compatibility with + IMAP2bis", RFC 2061, December 1996. + + [IMAP-HISTORICAL] Crispin, M., "IMAP4 Compatibility with IMAP2 + and IMAP2bis", RFC 1732, December 1994. + + [IMAP-OBSOLETE] Crispin, M., "Internet Message Access Protocol + - Obsolete Syntax", RFC 2062, December 1996. + + [IMAP2] Crispin, M., "Interactive Mail Access Protocol + - Version 2", RFC 1176, August 1990. + + [RFC-822] Crocker, D., "Standard for the Format of ARPA + Internet Text Messages", STD 11, RFC 822, + August 1982. + + [RFC-821] Postel, J., "Simple Mail Transfer Protocol", + STD 10, RFC 821, August 1982. + +B. Changes from RFC 2060 + + 1) Clarify description of unique identifiers and their semantics. + + 2) Fix the SELECT description to clarify that UIDVALIDITY is required + in the SELECT and EXAMINE responses. + + 3) Added an example of a failing search. + + 4) Correct store-att-flags: "#flag" should be "1#flag". + + 5) Made search and section rules clearer. + + 6) Correct the STORE example. + + 7) Correct "BASE645" misspelling. + + 8) Remove extraneous close parenthesis in example of two-part message + with text and BASE64 attachment. + + + +Crispin Standards Track [Page 97] + +RFC 3501 IMAPv4 March 2003 + + + 9) Remove obsolete "MAILBOX" response from mailbox-data. + + 10) A spurious "<" in the rule for mailbox-data was removed. + + 11) Add CRLF to continue-req. + + 12) Specifically exclude "]" from the atom in resp-text-code. + + 13) Clarify that clients and servers should adhere strictly to the + protocol syntax. + + 14) Emphasize in 5.2 that EXISTS can not be used to shrink a mailbox. + + 15) Add NEWNAME to resp-text-code. + + 16) Clarify that the empty string, not NIL, is used as arguments to + LIST. + + 17) Clarify that NIL can be returned as a hierarchy delimiter for the + empty string mailbox name argument if the mailbox namespace is flat. + + 18) Clarify that addr-mailbox and addr-name have RFC-2822 quoting + removed. + + 19) Update UTF-7 reference. + + 20) Fix example in 6.3.11. + + 21) Clarify that non-existent UIDs are ignored. + + 22) Update DISPOSITION reference. + + 23) Expand state diagram. + + 24) Clarify that partial fetch responses are only returned in + response to a partial fetch command. + + 25) Add UIDNEXT response code. Correct UIDVALIDITY definition + reference. + + 26) Further clarification of "can" vs. "MAY". + + 27) Reference RFC-2119. + + 28) Clarify that superfluous shifts are not permitted in modified + UTF-7. + + 29) Clarify that there are no implicit shifts in modified UTF-7. + + + +Crispin Standards Track [Page 98] + +RFC 3501 IMAPv4 March 2003 + + + 30) Clarify that "INBOX" in a mailbox name is always INBOX, even if + it is given as a string. + + 31) Add missing open parenthesis in media-basic grammar rule. + + 32) Correct attribute syntax in mailbox-data. + + 33) Add UIDNEXT to EXAMINE responses. + + 34) Clarify UNSEEN, PERMANENTFLAGS, UIDVALIDITY, and UIDNEXT + responses in SELECT and EXAMINE. They are required now, but weren't + in older versions. + + 35) Update references with RFC numbers. + + 36) Flush text-mime2. + + 37) Clarify that modified UTF-7 names must be case-sensitive and that + violating the convention should be avoided. + + 38) Correct UID FETCH example. + + 39) Clarify UID FETCH, UID STORE, and UID SEARCH vs. untagged EXPUNGE + responses. + + 40) Clarify the use of the word "convention". + + 41) Clarify that a command is not "in progress" until it has been + fully received (specifically, that a command is not "in progress" + during command continuation negotiation). + + 42) Clarify envelope defaulting. + + 43) Clarify that SP means one and only one space character. + + 44) Forbid silly states in LIST response. + + 45) Clarify that the ENVELOPE, INTERNALDATE, RFC822*, BODY*, and UID + for a message is static. + + 46) Add BADCHARSET response code. + + 47) Update formal syntax to [ABNF] conventions. + + 48) Clarify trailing hierarchy delimiter in CREATE semantics. + + 49) Clarify that the "blank line" is the [RFC-2822] delimiting blank + line. + + + +Crispin Standards Track [Page 99] + +RFC 3501 IMAPv4 March 2003 + + + 50) Clarify that RENAME should also create hierarchy as needed for + the command to complete. + + 51) Fix body-ext-mpart to not require language if disposition + present. + + 52) Clarify the RFC822.HEADER response. + + 53) Correct missing space after charset astring in search. + + 54) Correct missing quote for BADCHARSET in resp-text-code. + + 55) Clarify that ALL, FAST, and FULL preclude any other data items + appearing. + + 56) Clarify semantics of reference argument in LIST. + + 57) Clarify that a null string for SEARCH HEADER X-FOO means any + message with a header line with a field-name of X-FOO regardless of + the text of the header. + + 58) Specifically reserve 8-bit mailbox names for future use as UTF-8. + + 59) It is not an error for the client to store a flag that is not in + the PERMANENTFLAGS list; however, the server will either ignore the + change or make the change in the session only. + + 60) Correct/clarify the text regarding superfluous shifts. + + 61) Correct typographic errors in the "Changes" section. + + 62) Clarify that STATUS must not be used to check for new messages in + the selected mailbox + + 63) Clarify LSUB behavior with "%" wildcard. + + 64) Change AUTHORIZATION to AUTHENTICATE in section 7.5. + + 65) Clarify description of multipart body type. + + 66) Clarify that STORE FLAGS does not affect \Recent. + + 67) Change "west" to "east" in description of timezone. + + 68) Clarify that commands which break command pipelining must wait + for a completion result response. + + 69) Clarify that EXAMINE does not affect \Recent. + + + +Crispin Standards Track [Page 100] + +RFC 3501 IMAPv4 March 2003 + + + 70) Make description of MIME structure consistent. + + 71) Clarify that date searches disregard the time and timezone of the + INTERNALDATE or Date: header. In other words, "ON 13-APR-2000" means + messages with an INTERNALDATE text which starts with "13-APR-2000", + even if timezone differential from the local timezone is sufficient + to move that INTERNALDATE into the previous or next day. + + 72) Clarify that the header fetches don't add a blank line if one + isn't in the [RFC-2822] message. + + 73) Clarify (in discussion of UIDs) that messages are immutable. + + 74) Add an example of CHARSET searching. + + 75) Clarify in SEARCH that keywords are a type of flag. + + 76) Clarify the mandatory nature of the SELECT data responses. + + 77) Add optional CAPABILITY response code in the initial OK or + PREAUTH. + + 78) Add note that server can send an untagged CAPABILITY command as + part of the responses to AUTHENTICATE and LOGIN. + + 79) Remove statement about it being unnecessary to issue a CAPABILITY + command more than once in a connection. That statement is no longer + true. + + 80) Clarify that untagged EXPUNGE decrements the number of messages + in the mailbox. + + 81) Fix definition of "body" (concatenation has tighter binding than + alternation). + + 82) Add a new "Special Notes to Implementors" section with reference + to [IMAP-IMPLEMENTATION]. + + 83) Clarify that an untagged CAPABILITY response to an AUTHENTICATE + command should only be done if a security layer was not negotiated. + + 84) Change the definition of atom to exclude "]". Update astring to + include "]" for compatibility with the past. Remove resp-text-atom. + + 85) Remove NEWNAME. It can't work because mailbox names can be + literals and can include "]". Functionality can be addressed via + referrals. + + + + +Crispin Standards Track [Page 101] + +RFC 3501 IMAPv4 March 2003 + + + 86) Move modified UTF-7 rationale in order to have more logical + paragraph flow. + + 87) Clarify UID uniqueness guarantees with the use of MUST. + + 88) Note that clients should read response data until the connection + is closed instead of immediately closing on a BYE. + + 89) Change RFC-822 references to RFC-2822. + + 90) Clarify that RFC-2822 should be followed instead of RFC-822. + + 91) Change recommendation of optional automatic capabilities in LOGIN + and AUTHENTICATE to use the CAPABILITY response code in the tagged + OK. This is more interoperable than an unsolicited untagged + CAPABILITY response. + + 92) STARTTLS and AUTH=PLAIN are mandatory to implement; add + recommendations for other [SASL] mechanisms. + + 93) Clarify that a "connection" (as opposed to "server" or "command") + is in one of the four states. + + 94) Clarify that a failed or rejected command does not change state. + + 95) Split references between normative and informative. + + 96) Discuss authentication failure issues in security section. + + 97) Clarify that a data item is not necessarily of only one data + type. + + 98) Clarify that sequence ranges are independent of order. + + 99) Change an example to clarify that superfluous shifts in + Modified-UTF7 can not be fixed just by omitting the shift. The + entire string must be recalculated. + + 100) Change Envelope Structure definition since [RFC-2822] uses + "envelope" to refer to the [SMTP] envelope and not the envelope data + that appears in the [RFC-2822] header. + + 101) Expand on RFC822.HEADER response data vs. BODY[HEADER]. + + 102) Clarify Logout state semantics, change ASCII art. + + 103) Security changes to comply with IESG requirements. + + + + +Crispin Standards Track [Page 102] + +RFC 3501 IMAPv4 March 2003 + + + 104) Add definition for body URI. + + 105) Break sequence range definition into three rules, with rewritten + descriptions for each. + + 106) Move STARTTLS and LOGINDISABLED here from [IMAP-TLS]. + + 107) Add IANA Considerations section. + + 108) Clarify valid client assumptions for new message UIDs vs. + UIDNEXT. + + 109) Clarify that changes to permanentflags affect concurrent + sessions as well as subsequent sessions. + + 110) Clarify that authenticated state can be entered by the CLOSE + command. + + 111) Emphasize that SELECT and EXAMINE are the exceptions to the rule + that a failing command does not change state. + + 112) Clarify that newly-appended messages have the Recent flag set. + + 113) Clarify that newly-copied messages SHOULD have the Recent flag + set. + + 114) Clarify that UID commands always return the UID in FETCH + responses. + +C. Key Word Index + + +FLAGS <flag list> (store command data item) ............... 59 + +FLAGS.SILENT <flag list> (store command data item) ........ 59 + -FLAGS <flag list> (store command data item) ............... 59 + -FLAGS.SILENT <flag list> (store command data item) ........ 59 + ALERT (response code) ...................................... 64 + ALL (fetch item) ........................................... 55 + ALL (search key) ........................................... 50 + ANSWERED (search key) ...................................... 50 + APPEND (command) ........................................... 45 + AUTHENTICATE (command) ..................................... 27 + BAD (response) ............................................. 66 + BADCHARSET (response code) ................................. 64 + BCC <string> (search key) .................................. 51 + BEFORE <date> (search key) ................................. 51 + BODY (fetch item) .......................................... 55 + BODY (fetch result) ........................................ 73 + BODY <string> (search key) ................................. 51 + + + +Crispin Standards Track [Page 103] + +RFC 3501 IMAPv4 March 2003 + + + BODY.PEEK[<section>]<<partial>> (fetch item) ............... 57 + BODYSTRUCTURE (fetch item) ................................. 57 + BODYSTRUCTURE (fetch result) ............................... 74 + BODY[<section>]<<origin octet>> (fetch result) ............. 74 + BODY[<section>]<<partial>> (fetch item) .................... 55 + BYE (response) ............................................. 67 + Body Structure (message attribute) ......................... 12 + CAPABILITY (command) ....................................... 24 + CAPABILITY (response code) ................................. 64 + CAPABILITY (response) ...................................... 68 + CC <string> (search key) ................................... 51 + CHECK (command) ............................................ 47 + CLOSE (command) ............................................ 48 + COPY (command) ............................................. 59 + CREATE (command) ........................................... 34 + DELETE (command) ........................................... 35 + DELETED (search key) ....................................... 51 + DRAFT (search key) ......................................... 51 + ENVELOPE (fetch item) ...................................... 57 + ENVELOPE (fetch result) .................................... 77 + EXAMINE (command) .......................................... 33 + EXISTS (response) .......................................... 71 + EXPUNGE (command) .......................................... 48 + EXPUNGE (response) ......................................... 72 + Envelope Structure (message attribute) ..................... 12 + FAST (fetch item) .......................................... 55 + FETCH (command) ............................................ 54 + FETCH (response) ........................................... 73 + FLAGGED (search key) ....................................... 51 + FLAGS (fetch item) ......................................... 57 + FLAGS (fetch result) ....................................... 78 + FLAGS (response) ........................................... 71 + FLAGS <flag list> (store command data item) ................ 59 + FLAGS.SILENT <flag list> (store command data item) ......... 59 + FROM <string> (search key) ................................. 51 + FULL (fetch item) .......................................... 55 + Flags (message attribute) .................................. 11 + HEADER (part specifier) .................................... 55 + HEADER <field-name> <string> (search key) .................. 51 + HEADER.FIELDS <header-list> (part specifier) ............... 55 + HEADER.FIELDS.NOT <header-list> (part specifier) ........... 55 + INTERNALDATE (fetch item) .................................. 57 + INTERNALDATE (fetch result) ................................ 78 + Internal Date (message attribute) .......................... 12 + KEYWORD <flag> (search key) ................................ 51 + Keyword (type of flag) ..................................... 11 + LARGER <n> (search key) .................................... 51 + LIST (command) ............................................. 40 + + + +Crispin Standards Track [Page 104] + +RFC 3501 IMAPv4 March 2003 + + + LIST (response) ............................................ 69 + LOGIN (command) ............................................ 30 + LOGOUT (command) ........................................... 25 + LSUB (command) ............................................. 43 + LSUB (response) ............................................ 70 + MAY (specification requirement term) ....................... 4 + MESSAGES (status item) ..................................... 45 + MIME (part specifier) ...................................... 56 + MUST (specification requirement term) ...................... 4 + MUST NOT (specification requirement term) .................. 4 + Message Sequence Number (message attribute) ................ 10 + NEW (search key) ........................................... 51 + NO (response) .............................................. 66 + NOOP (command) ............................................. 25 + NOT <search-key> (search key) .............................. 52 + OK (response) .............................................. 65 + OLD (search key) ........................................... 52 + ON <date> (search key) ..................................... 52 + OPTIONAL (specification requirement term) .................. 4 + OR <search-key1> <search-key2> (search key) ................ 52 + PARSE (response code) ...................................... 64 + PERMANENTFLAGS (response code) ............................. 64 + PREAUTH (response) ......................................... 67 + Permanent Flag (class of flag) ............................. 12 + READ-ONLY (response code) .................................. 65 + READ-WRITE (response code) ................................. 65 + RECENT (response) .......................................... 72 + RECENT (search key) ........................................ 52 + RECENT (status item) ....................................... 45 + RENAME (command) ........................................... 37 + REQUIRED (specification requirement term) .................. 4 + RFC822 (fetch item) ........................................ 57 + RFC822 (fetch result) ...................................... 78 + RFC822.HEADER (fetch item) ................................. 57 + RFC822.HEADER (fetch result) ............................... 78 + RFC822.SIZE (fetch item) ................................... 57 + RFC822.SIZE (fetch result) ................................. 78 + RFC822.TEXT (fetch item) ................................... 58 + RFC822.TEXT (fetch result) ................................. 79 + SEARCH (command) ........................................... 49 + SEARCH (response) .......................................... 71 + SEEN (search key) .......................................... 52 + SELECT (command) ........................................... 31 + SENTBEFORE <date> (search key) ............................. 52 + SENTON <date> (search key) ................................. 52 + SENTSINCE <date> (search key) .............................. 52 + SHOULD (specification requirement term) .................... 4 + SHOULD NOT (specification requirement term) ................ 4 + + + +Crispin Standards Track [Page 105] + +RFC 3501 IMAPv4 March 2003 + + + SINCE <date> (search key) .................................. 52 + SMALLER <n> (search key) ................................... 52 + STARTTLS (command) ......................................... 27 + STATUS (command) ........................................... 44 + STATUS (response) .......................................... 70 + STORE (command) ............................................ 58 + SUBJECT <string> (search key) .............................. 53 + SUBSCRIBE (command) ........................................ 38 + Session Flag (class of flag) ............................... 12 + System Flag (type of flag) ................................. 11 + TEXT (part specifier) ...................................... 56 + TEXT <string> (search key) ................................. 53 + TO <string> (search key) ................................... 53 + TRYCREATE (response code) .................................. 65 + UID (command) .............................................. 60 + UID (fetch item) ........................................... 58 + UID (fetch result) ......................................... 79 + UID <sequence set> (search key) ............................ 53 + UIDNEXT (response code) .................................... 65 + UIDNEXT (status item) ...................................... 45 + UIDVALIDITY (response code) ................................ 65 + UIDVALIDITY (status item) .................................. 45 + UNANSWERED (search key) .................................... 53 + UNDELETED (search key) ..................................... 53 + UNDRAFT (search key) ....................................... 53 + UNFLAGGED (search key) ..................................... 53 + UNKEYWORD <flag> (search key) .............................. 53 + UNSEEN (response code) ..................................... 65 + UNSEEN (search key) ........................................ 53 + UNSEEN (status item) ....................................... 45 + UNSUBSCRIBE (command) ...................................... 39 + Unique Identifier (UID) (message attribute) ................ 8 + X<atom> (command) .......................................... 62 + [RFC-2822] Size (message attribute) ........................ 12 + \Answered (system flag) .................................... 11 + \Deleted (system flag) ..................................... 11 + \Draft (system flag) ....................................... 11 + \Flagged (system flag) ..................................... 11 + \Marked (mailbox name attribute) ........................... 69 + \Noinferiors (mailbox name attribute) ...................... 69 + \Noselect (mailbox name attribute) ......................... 69 + \Recent (system flag) ...................................... 11 + \Seen (system flag) ........................................ 11 + \Unmarked (mailbox name attribute) ......................... 69 + + + + + + + +Crispin Standards Track [Page 106] + +RFC 3501 IMAPv4 March 2003 + + +Author's Address + + Mark R. Crispin + Networks and Distributed Computing + University of Washington + 4545 15th Avenue NE + Seattle, WA 98105-4527 + + Phone: (206) 543-5762 + + EMail: MRC@CAC.Washington.EDU + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 107] + +RFC 3501 IMAPv4 March 2003 + + +Full Copyright Statement + + Copyright (C) The Internet Society (2003). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assigns. v This + document and the information contained herein is provided on an "AS + IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK + FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT + LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL + NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY + OR FITNESS FOR A PARTICULAR PURPOSE. + +Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society. + + + + + + + + + + + + + + + + + + + + +Crispin Standards Track [Page 108] + |