RFC 1730

] The text of a particular body section. The section specification is a set of one or more part numbers delimited by periods. Single-part messages only have a part 1. Crispin [Page 29] RFC 1730 IMAP4 December 1994 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. It is not permitted to fetch a multipart part itself, only its individual members. A part of type MESSAGE and subtype RFC822 also has nested parts. These are the parts of the MESSAGE part's body. Nested part 0 of a part of type MESSAGE and subtype RFC822 is the [RFC-822] header of the message. Every message has at least one part. Here is an example of a complex message with its associated section specifications: 0 ([RFC-822] header of the message) MULTIPART/MIXED 1 TEXT/PLAIN 2 APPLICATION/OCTET-STREAM 3 MESSAGE/RFC822 3.0 ([RFC-822] header of the message) 3.1 TEXT/PLAIN 3.2 APPLICATION/OCTET-STREAM MULTIPART/MIXED 4.1 IMAGE/GIF 4.2 MESSAGE/RFC822 4.2.0 ([RFC-822] header of the message) 4.2.1 TEXT/PLAIN MULTIPART/ALTERNATIVE 4.2.2.1 TEXT/PLAIN 4.2.2.2 TEXT/RICHTEXT Note that there is no section specification for the Multi-part parts (no section 4 or 4.2.2). 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[

] An alternate form of BODY[section] that does not implicitly set the \Seen flag. Crispin [Page 30] RFC 1730 IMAP4 December 1994 BODYSTRUCTURE The [MIME-1] body structure of the message. This is computed by the server by parsing the [MIME-1] header lines. ENVELOPE The envelope structure of the message. This is computed by the server by parsing the [RFC-822] header into the component parts, defaulting various fields as necessary. FAST Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE) FLAGS The flags that are set for this message. FULL Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE BODY) INTERNALDATE The date and time of final delivery of the message as defined by RFC 821. RFC822 The message in [RFC-822] format. The \Seen flag is implicitly set; if this causes the flags to change they should be included as part of the fetch responses. This is the concatenation of RFC822.HEADER and RFC822.TEXT. RFC822.PEEK An alternate form of RFC822 that does not implicitly set the \Seen flag. RFC822.HEADER The [RFC-822] format header of the message as stored on the server including the delimiting blank line between the header and the body. RFC822.HEADER.LINES All header lines (including continuation lines) of the [RFC-822] format header of the message with a field-name (as defined in [RFC-822]) that matches any of the strings in header_list. The matching is case-insensitive but otherwise exact. The delimiting blank line between the header and the body is always included. Crispin [Page 31] RFC 1730 IMAP4 December 1994 RFC822.HEADER.LINES.NOT All header lines (including continuation lines) of the [RFC-822] format header of the message with a field-name (as defined in [RFC-822]) that does not match any of the strings in header_list. The matching is case-insensitive but otherwise exact. The delimiting blank line between the header and the body is always included. RFC822.SIZE The number of octets in the message, as expressed in [RFC-822] format. RFC822.TEXT The text body of the message, omitting the [RFC-822] header. The \Seen flag is implicitly set; if this causes the flags to change they should be included as part of the fetch responses. RFC822.TEXT.PEEK An alternate form of RFC822.TEXT that does not implicitly set the \Seen flag. UID The unique identifier for the message. Example: C: A654 FETCH 2:4 (FLAGS RFC822.HEADER.LINES (DATE FROM)) S: * 2 FETCH .... S: * 3 FETCH .... S: * 4 FETCH .... S: A003 OK FETCH completed 6.4.6. PARTIAL Command Arguments: message sequence number message data item name position of first octet number of octets Data: untagged responses: FETCH Result: OK - partial completed NO - partial error: can't fetch that data BAD - command unknown or arguments invalid The PARTIAL command is equivalent to the associated FETCH command, with the added functionality that only the specified number of octets, beginning at the specified starting octet, are returned. Only a single message can be fetched at a time. The first octet Crispin [Page 32] RFC 1730 IMAP4 December 1994 of a message, and hence the minimum for the starting octet, is octet 1. The following FETCH items are valid data for PARTIAL: RFC822, RFC822.HEADER, RFC822.TEXT, BODY[section], as well as any .PEEK forms of these. Any partial fetch that attempts to read beyond the end of the text is truncated as appropriate. If the starting octet is beyond the end of the text, an empty string is returned. The data are returned with the FETCH response. There is no indication of the range of the partial data in this response. It is not possible to stream multiple PARTIAL commands of the same data item without processing and synchronizing at each step, since streamed commands may be executed out of order. There is no requirement that partial fetches follow any sequence. For example, if a partial fetch of octets 1 through 10000 breaks in an awkward place for BASE64 decoding, it is permitted to continue with a partial fetch of 9987 through 19987, etc. The handling of the \Seen flag is the same as in the associated FETCH command. Example: C: A005 PARTIAL 4 RFC822 1 1024 S: * 1 FETCH (RFC822 {1024} S: Return-Path: S: ... S: ......... FLAGS (\Seen)) S: A005 OK PARTIAL completed 6.4.7. STORE Command Arguments: message set message data item name value for message data item Data: 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 Crispin [Page 33] RFC 1730 IMAP4 December 1994 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. The currently defined data items that can be stored are: FLAGS Replace the flags for the message with the argument. The new value of the flags are returned as if a FETCH of those flags was done. FLAGS.SILENT Equivalent to FLAGS, but without returning a new value. +FLAGS Add the argument to the flags for the message. The new value of the flags are returned as if a FETCH of those flags was done. +FLAGS.SILENT Equivalent to +FLAGS, but without returning a new value. -FLAGS Remove the argument from the flags for the message. The new value of the flags are returned as if a FETCH of those flags was done. -FLAGS.SILENT 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 Crispin [Page 34] RFC 1730 IMAP4 December 1994 6.4.8. COPY Command Arguments: message set mailbox name Data: no specific data 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 The COPY command copies the specified message(s) to the specified destination mailbox. The flags and internal date of the message(s) SHOULD be preserved 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 6.4.9. UID Command Arguments: command name command arguments Data: 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 message set argument are unique identifiers instead of message sequence numbers. Crispin [Page 35] RFC 1730 IMAP4 December 1994 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 of message sequence numbers. For example, the command UID SEARCH 1:100 UID 443:557 returns the unique identifiers corresponding to the intersection of the message sequence number set 1:100 and the UID set 443:557. A unique identifier of a message is a number, and is guaranteed not to refer to any other message in the mailbox. Unique identifiers are assigned in a strictly ascending fashion for each message added to the mailbox. Unlike message sequence numbers, unique identifiers persist across sessions. This permits 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]. Associated with every mailbox is a unique identifier validity value, which is sent in an UIDVALIDITY response code in an OK untagged response at message selection time. If unique identifiers from an earlier session fail to persist to this session, the unique identifier validity value MUST be greater than in the earlier session. Note: An example of a good value to use for the unique identifier validity value would be 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 identifers will never be reused, even in the case of a mailbox being deleted and a new mailbox by the same name created at some future time. Message set ranges are permitted; however, there is no guarantee that unique identifiers be contiguous. A non-existent unique identifier within a message set range is ignored without any error message generated. 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 UID was specified as a message data item to the FETCH. Crispin [Page 36] RFC 1730 IMAP4 December 1994 Example: C: A003 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 UID FETCH completed 6.5. Client Commands - Experimental/Expansion 6.5.1. X Command Arguments: implementation defined Data: 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, or a standard or standards-track revision of this specification, 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 IMAP4 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 Crispin [Page 37] RFC 1730 IMAP4 December 1994 7. Server Responses Server responses are in three forms: status responses, server data, and command continuation request. Server response data, identified by "Data:" in the response descriptions below, are described by function, not by syntax. The precise syntax of server response data is described in the Formal Syntax section. The client MUST be prepared to accept any response at all times. Status responses that are tagged indicate the completion result 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 that does not indicate the completion of a command. 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 messags). 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 responses occurs when the IMAP connection is in selected state. In selected state, the server checks the mailbox for new messages as part of the execution of each command. 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. Crispin [Page 38] RFC 1730 IMAP4 December 1994 7.1. Server Responses - Status Responses 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. 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. PARSE The human-readable text represents an error in parsing the [RFC-822] or [MIME-1] headers of a message in the mailbox. PERMANENTFLAGS Followed by a parenthesized list of flags, indicates which of the known flags that the client may 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 reject it with a NO reply or store the state for the remainder of the current session only. The PERMANENTFLAGS list may also include the special flag \*, which indicates that it is possible to create new keywords by attempting to store those flags in the mailbox. 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 may succeed if the mailbox is first created by the CREATE command. Crispin [Page 39] RFC 1730 IMAP4 December 1994 UIDVALIDITY Followed by a decimal number, indicates the unique identifier validity value. See the description of the UID command for more detail. 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 Data: 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 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 session startup. It indicates that the session is not yet authenticated and that a LOGIN command is needed. Example: S: * OK IMAP4 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 Data: 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 may still complete successfully. The human-readable text describes the condition. Crispin [Page 40] RFC 1730 IMAP4 December 1994 Example: C: A222 COPY 1:2 owatagusiam S: * NO Disk is 98% full, please delete unnecessary data S: A222 OK COPY completed C: A222 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: A222 NO COPY failed: disk is full 7.1.3. BAD Response Data: 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 may also indicate an internal server failure. The human-readable text describes the condition. 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 Data: optional response code human-readable text The PREAUTH response is always untagged, and is one of three possible greetings at session startup. It indicates that the session has already been authenticated by external means and thus no LOGIN command is needed. Example: S: * PREAUTH IMAP4 server ready and logged in as Smith Crispin [Page 41] RFC 1730 IMAP4 December 1994 7.1.5. BYE Response Data: 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 may be sent as part of a normal logout sequence, or as a panic shutdown announcement by the server. It is also used by some server implementations as an announcement of an inactivity autologout. This response is also used as one of three possible greetings at session startup. It indicates that the server is not willing to accept a session from this client. 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 data are transmitted from the server to the client, often as a result of a command with the same name. 7.2.1. CAPABILITY Response Data: 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 first name in the capability listing MUST be the atom "IMAP4". A capability name other than IMAP4 indicates that the server supports an extension, revision, or amendment to the IMAP4 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 IMAP4 extensions, revisions, or amendments registered with IANA. A server MUST NOT offer unregistered or non-standard capability names, unless such names are prefixed with an "X". Crispin [Page 42] RFC 1730 IMAP4 December 1994 Client implementations SHOULD NOT require any capability name other than "IMAP4", and MUST ignore any unknown capability names. Example: S: * CAPABILITY IMAP4 XPIG-LATIN 7.2.2. LIST Response Data: 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 may 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. If it is not feasible for the server to determine whether the mailbox is "interesting" or not, 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 may 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. Crispin [Page 43] RFC 1730 IMAP4 December 1994 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 Data: 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 may 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. SEARCH Response Data: 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 7.2.5. FLAGS Response Data: 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 may 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) Crispin [Page 44] RFC 1730 IMAP4 December 1994 7.3. 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 either a message sequence number or a message count. 7.3.1. EXISTS Response Data: 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 mail). The update from the EXISTS response MUST be recorded by the client. Example: S: * 23 EXISTS 7.3.2. RECENT Response Data: none The RECENT response reports the number of messages that have arrived since the previous time a SELECT command was done on this mailbox. This response occurs as a result of a SELECT or EXAMINE command, and if the size of the mailbox changes (e.g. new mail). The update from the RECENT response MUST be recorded by the client. Example: S: * 5 RECENT 7.3.3. EXPUNGE Response Data: 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 [Page 45] RFC 1730 IMAP4 December 1994 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. The update from the EXPUNGE response MUST be recorded by the client. Example: S: * 44 EXPUNGE 7.3.4. FETCH Response Data: 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. BODY[section] 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. 8-bit textual data is permitted if a character set identifier is part of the body parameter parenthesized list for this section. 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 Crispin [Page 46] RFC 1730 IMAP4 December 1994 original binary data, the client must decode the transfer encoded string. BODYSTRUCTURE A parenthesized list that describes the body structure of a message. This is computed by the server by parsing the [RFC-822] header and body into the component parts, defaulting various fields as necessary. Multiple parts are indicated by parenthesis nesting. Instead of a body type as the first element of the parenthesized list there is a nested body. The second element of the parenthesized list is the multipart subtype (mixed, digest, parallel, alternative, etc.). Extension data follows the multipart subtype. Extension data is never returned with the BODY fetch, but may 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-1]. Any following extension data are not yet defined in this version of the protocol. Such extension data may 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 type name as defined in [MIME-1]. Crispin [Page 47] RFC 1730 IMAP4 December 1994 body subtype A string giving the content subtype name as defined in [MIME-1]. 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-1]. body id A string giving the content id as defined in [MIME-1]. body description A string giving the content description as defined in [MIME-1]. body encoding A string giving the content transfer encoding as defined in [MIME-1]. 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 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 may 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: Crispin [Page 48] RFC 1730 IMAP4 December 1994 body MD5 A string giving the content MD5 value as defined in [MIME-1]. 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-822] 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-822] 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. Any field of an envelope or address structure that is not applicable is presented as NIL. Note that the server must default the reply-to and sender fields from the from field; a client is not expected to know to do this. Crispin [Page 49] RFC 1730 IMAP4 December 1994 FLAGS A parenthesized list of flags that are set for this message. This may include keywords as well as the following system flags: \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). as well as the following special flag, which may be fetched but not stored: \Recent Message has arrived since the previous time this mailbox was selected. INTERNALDATE A string containing the date and time of final delivery of the message as defined by [SMTP]. RFC822 A string expressing the message in [RFC-822] format. The header portion of the message must be 7-bit. 8-bit characters are permitted only in the non-header portion of the message only if there are [MIME-1] data in the message that identify the character set of the message. RFC822.HEADER A string expressing the [RFC-822] format header of the message, including the delimiting blank line between the header and the body. The entire string must be 7-bit; 8-bit characters are not permitted in headers. RFC822.HEADER is used to return data for the RFC822.HEADER, RFC822.HEADER.LINES, and RFC822.HEADER.LINES.NOT FETCH data items. Note that a blank line is always included regardless of header line restrictions. RFC822.SIZE A number expressing the number of octets in the message in [RFC-822] format. Crispin [Page 50] RFC 1730 IMAP4 December 1994 RFC822.TEXT A string expressing the text body of the message, omitting the [RFC-822] header. 8-bit characters are permitted only if there are [MIME-1] data in the message that identify the character set of the message. UID A number expressing the unique identifier of the message. Example: S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827) 7.3.5. Obsolete Responses In addition to the responses listed in here, client implementations MUST accept and implement the obsolete responses described in Appendix B. 7.4. Server Responses - Command Continuation Request The command completion 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 AUTHORIZATION 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 expects it. 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 [Page 51] RFC 1730 IMAP4 December 1994 8. Sample IMAP4 session The following is a transcript of an IMAP4 session. A long line in this sample is broken for editorial clarity. S: * OK IMAP4 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 "14-Jul-1993 02:44:25 -0700" RFC822.SIZE 4282 ENVELOPE ("Wed, 14 Jul 1993 02:23:25 -0700 (PDT)" "IMAP4 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" "INFOODS.MIT.EDU")) NIL NIL "") BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 3028 92)) S: a003 OK FETCH completed C: a004 fetch 12 rfc822.header S: * 12 FETCH (RFC822.HEADER {346} S: Date: Wed, 14 Jul 1993 02:23:25 -0700 (PDT) S: From: Terry Gray S: Subject: IMAP4 WG mtg summary and minutes S: To: imap@cac.washington.edu S: cc: minutes@CNRI.Reston.VA.US, John Klensin S: Message-Id: 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 IMAP4 server terminating connection S: a006 OK LOGOUT completed Crispin [Page 52] RFC 1730 IMAP4 December 1994 9. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) notation as specified in [RFC-822] with one exception; the delimiter used with the "#" construct is a single space (SPACE) and not a comma. 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. Syntax marked as obsolete may be encountered with implementations written for an earlier version of this protocol (e.g. IMAP2). New implementations SHOULD accept obsolete syntax as input, but MUST NOT otherwise use such syntax. address ::= "(" addr_name SPACE addr_adl SPACE addr_mailbox SPACE addr_host ")" addr_adl ::= nstring addr_host ::= nstring ;; NIL indicates [RFC-822] group syntax addr_mailbox ::= nstring ;; NIL indicates end of [RFC-822] group; if ;; non-NIL and addr_host is NIL, holds ;; [RFC-822] group name addr_name ::= nstring alpha ::= "A" / "B" / "C" / "D" / "E" / "F" / "G" / "H" / "I" / "J" / "K" / "L" / "M" / "N" / "O" / "P" / "Q" / "R" / "S" / "T" / "U" / "V" / "W" / "X" / "Y" / "Z" / "a" / "b" / "c" / "d" / "e" / "f" / "g" / "h" / "i" / "j" / "k" / "l" / "m" / "n" / "o" / "p" / "q" / "r" / "s" / "t" / "u" / "v" / "w" / "x" / "y" / "z" / ;; Case-sensitive append ::= "APPEND" SPACE mailbox [SPACE flag_list] [SPACE date_time] SPACE literal astring ::= atom / string Crispin [Page 53] RFC 1730 IMAP4 December 1994 atom ::= 1*ATOM_CHAR ATOM_CHAR ::= atom_specials ::= "(" / ")" / "{" / SPACE / CTLs / list_wildcards / quoted_specials authenticate ::= "AUTHENTICATE" SPACE auth_type *(CRLF base64) auth_type ::= atom base64 ::= *(4base64_char) [base64_terminal] base64_char ::= alpha / digit / "+" / "/" base64_terminal ::= (2base64_char "==") / (3base64_char "=") body ::= "(" body_type_1part / body_type_mpart ")" body_extension ::= nstring / number / "(" 1#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 [SPACE 1#body_extension] ;; MUST NOT be returned on non-extensible ;; "BODY" fetch body_ext_mpart ::= body_fld_param [SPACE 1#body_extension]] ;; MUST NOT be returned on non-extensible ;; "BODY" fetch body_fields ::= body_fld_param SPACE body_fld_id SPACE body_fld_desc SPACE body_fld_enc SPACE body_fld_octets body_fld_desc ::= nstring body_fld_enc ::= (<"> ("7BIT" / "8BIT" / "BINARY" / "BASE64"/ "QUOTED-PRINTABLE") <">) / string body_fld_id ::= nstring body_fld_lines ::= number Crispin [Page 54] RFC 1730 IMAP4 December 1994 body_fld_md5 ::= nstring body_fld_octets ::= number body_fld_param ::= "(" 1#(string string) ")" / nil body_fld_subtyp ::= string body_type_1part ::= (body_type_basic / body_type_msg / body_type_text) [SPACE body_ext_1part] body_type_basic ::= (<"> ("APPLICATION" / "AUDIO" / "IMAGE" / "MESSAGE" / "VIDEO") <">) / string) SPACE body_fld_subtyp SPACE body_fields ;; MESSAGE subtype MUST NOT be "RFC822" body_type_mpart ::= 1*body SPACE body_fld_subtyp [SPACE body_ext_mpart] body_type_msg ::= <"> "MESSAGE" <"> SPACE <"> "RFC822" <"> SPACE body_fields SPACE envelope SPACE body SPACE body_fld_lines body_type_text ::= <"> "TEXT" <"> SPACE body_fld_subtyp SPACE body_fields SPACE body_fld_lines capability ::= atom ;; Must begin with "X" or be registered with ;; IANA as standard or standards-track capability_data ::= "CAPABILITY" SPACE "IMAP4" [SPACE 1#capability] CHAR ::= CHAR8 ::= command ::= tag SPACE (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 / find / list / lsub / rename / select / subscribe / unsubscribe / ;; Valid only in Authenticated or Selected state Crispin [Page 55] RFC 1730 IMAP4 December 1994 command_nonauth ::= login / authenticate ;; Valid only when in Non-Authenticated state command_select ::= "CHECK" / "CLOSE" / "EXPUNGE" / copy / fetch / partial / store / uid / search ;; Valid only when in Selected state continue_req ::= "+" SPACE (resp_text / base64) copy ::= "COPY" SPACE set SPACE mailbox CR ::= create ::= "CREATE" SPACE mailbox ;; Use of INBOX gives a NO error CRLF ::= CR LF CTL ::= date ::= date_text / <"> date_text <"> date_day ::= 1*2digit ;; Day of month date_day_fixed ::= (SPACE 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 / date_year_old) date_year ::= 4digit date_year_old ::= 2digit ;; OBSOLETE, (year - 1900) date_time ::= <"> (date_time_new / date_time_old) <"> date_time_new ::= date_day_fixed "-" date_month "-" date_year SPACE time SPACE zone date_time_old ::= date_day_fixed "-" date_month "-" date_year_old SPACE time "-" zone_old ;; OBSOLETE Crispin [Page 56] RFC 1730 IMAP4 December 1994 delete ::= "DELETE" SPACE mailbox ;; Use of INBOX gives a NO error digit ::= "0" / digit_nz digit_nz ::= "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" envelope ::= "(" env_date SPACE env_subject SPACE env_from SPACE env_sender SPACE env_reply-to SPACE env_to SPACE env_cc SPACE env_bcc SPACE env_in-reply-to SPACE 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" SPACE mailbox fetch ::= "FETCH" SPACE set SPACE ("ALL" / "FULL" / "FAST" / fetch_att / "(" 1#fetch_att ")") fetch_att ::= "BODY" / "BODYSTRUCTURE" / "BODY" [".PEEK"] "[" section "]" / "ENVELOPE" / "FLAGS" / "INTERNALDATE" / "UID" / "RFC822" (([".TEXT"] [".PEEK"]) / ".SIZE" / (".HEADER" [".LINES" [".NOT"] SPACE header_list]) find ::= "FIND" SPACE ["ALL."] "MAILBOXES" SPACE list_mailbox ;; OBSOLETE Crispin [Page 57] RFC 1730 IMAP4 December 1994 flag ::= "\Answered" / "\Flagged" / "\Deleted" / "\Seen" / "\Draft" / flag_keyword / flag_extension 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_keyword ::= atom flag_list ::= "(" #flag ")" greeting ::= "*" SPACE (resp_cond_auth / resp_cond_bye) CRLF header_line ::= astring header_list ::= "(" 1#header_line ")" LF ::= list ::= "LIST" SPACE mailbox SPACE list_mailbox list_mailbox ::= 1*(ATOM_CHAR / list_wildcards) / string list_wildcards ::= "%" / "*" literal ::= "{" number "}" CRLF *CHAR8 ;; Number represents the number of CHAR8 octets login ::= "LOGIN" SPACE userid SPACE password lsub ::= "LSUB" SPACE mailbox SPACE list_mailbox mailbox ::= "INBOX" / astring ;; INBOX is case-insensitive; other names may be ;; case-sensitive depending on implementation. mailbox_data ::= "FLAGS" SPACE flag_list / "LIST" SPACE mailbox_list / "LSUB" SPACE mailbox_list / "MAILBOX" SPACE text / "SEARCH" [SPACE 1#nz_number] / number SPACE "EXISTS" / number SPACE "RECENT" Crispin [Page 58] RFC 1730 IMAP4 December 1994 mailbox_list ::= "(" #("\Marked" / "\Noinferiors" / "\Noselect" / "\Unmarked" / flag_extension) ")" SPACE (<"> QUOTED_CHAR <"> / nil) SPACE mailbox message_data ::= nz_number SPACE ("EXPUNGE" / ("FETCH" SPACE msg_fetch) / msg_obsolete) msg_fetch ::= "(" 1#("BODY" SPACE body / "BODYSTRUCTURE" SPACE body / "BODY[" section "]" SPACE nstring / "ENVELOPE" SPACE envelope / "FLAGS" SPACE "(" #(flag / "\Recent") ")" / "INTERNALDATE" SPACE date_time / "RFC822" [".HEADER" / ".TEXT"] SPACE nstring / "RFC822.SIZE" SPACE number / "UID" SPACE uniqueid) ")" msg_obsolete ::= "COPY" / ("STORE" SPACE msg_fetch) ;; OBSOLETE untagged data responses 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) partial ::= "PARTIAL" SPACE nz_number SPACE ("BODY" [".PEEK"] "[" section "]" / "RFC822" (([".TEXT"] [".PEEK"]) / ".HEADER") SPACE number SPACE number password ::= astring quoted ::= <"> *QUOTED_CHAR <"> QUOTED_CHAR ::= / "\" quoted_specials quoted_specials ::= <"> / "\" rename ::= "RENAME" SPACE mailbox SPACE mailbox ;; Use of INBOX as a destination gives a NO error Crispin [Page 59] RFC 1730 IMAP4 December 1994 response ::= *response_data response_done response_data ::= "*" SPACE (resp_cond_state / resp_cond_bye / mailbox_data / message_data / capability_data) CRLF response_done ::= response_tagged / response_fatal response_fatal ::= "*" SPACE resp_cond_bye CRLF response_tagged ::= tag SPACE resp_cond_state CRLF resp_cond_auth ::= ("OK" / "PREAUTH") SPACE resp_text ;; Authentication condition resp_cond_bye ::= "BYE" SPACE resp_text ;; Server will disconnect condition resp_cond_state ::= ("OK" / "NO" / "BAD") SPACE resp_text ;; Status condition resp_text ::= ["[" resp_text_code "]" SPACE] (text_mime2 / text) resp_text_code ::= "ALERT" / "PARSE" / "PERMANENTFLAGS" SPACE "(" #(flag / "\*") ")" / "READ-ONLY" / "READ-WRITE" / "TRYCREATE" / "UIDVALIDITY" SPACE nz_number / "UNSEEN" SPACE nz_number / atom [SPACE 1*] search ::= "SEARCH" SPACE ["CHARSET" SPACE astring SPACE] search_criteria ;; Character set must be registered with IANA ;; as a MIME character set search_criteria ::= 1#search_key search_key ::= search_new / search_old search_new ::= "DRAFT" / "HEADER" SPACE header_line SPACE astring / "LARGER" SPACE number / "NOT" SPACE search_key / "OR" SPACE search_key SPACE search_key / "SENTBEFORE" SPACE date / "SENTON" SPACE date / "SENTSINCE" SPACE date / "SMALLER" SPACE number / "UID" SPACE set / "UNDRAFT" / set / "(" search_criteria ")" ;; New in IMAP4 Crispin [Page 60] RFC 1730 IMAP4 December 1994 search_old ::= "ALL" / "ANSWERED" / "BCC" SPACE astring / "BEFORE" SPACE date / "BODY" SPACE astring / "CC" SPACE astring / "DELETED" / "FLAGGED" / "FROM" SPACE astring / "KEYWORD" SPACE flag_keyword / "NEW" / "OLD" / "ON" SPACE date / "RECENT" / "SEEN" / "SINCE" SPACE date / "SUBJECT" SPACE astring / "TEXT" SPACE astring / "TO" SPACE astring / "UNANSWERED" / "UNDELETED" / "UNFLAGGED" / "UNKEYWORD" SPACE flag_keyword / "UNSEEN" ;; Defined in [IMAP2] section ::= "0" / nz_number ["." section] select ::= "SELECT" SPACE mailbox sequence_num ::= nz_number / "*" ;; * is the largest number in use. For message ;; sequence numbers, it is the number of messages ;; in the mailbox. For unique identifiers, it is ;; the unique identifier of the last message in ;; the mailbox. set ::= sequence_num / (sequence_num ":" sequence_num) / (set "," set) ;; Identifies a set of messages. For message ;; sequence numbers, these are consecutive ;; numbers from 1 to the number of messages in ;; the mailbox ;; Comma delimits individual numbers, colon ;; delimits between two numbers inclusive. ;; Example: 2,4:7,9,12:* is 2,4,5,6,7,9,12,13, ;; 14,15 for a mailbox with 15 messages. SPACE ::= store ::= "STORE" SPACE set SPACE store_att_flags store_att_flags ::= (["+" / "-"] "FLAGS" [".SILENT"]) SPACE (flag_list / #flag) string ::= quoted / literal subscribe ::= ("SUBSCRIBE" SPACE mailbox) / subscribe_obs subscribe_obs ::= "SUBSCRIBE" SPACE "MAILBOX" SPACE mailbox ;;OBSOLETE Crispin [Page 61] RFC 1730 IMAP4 December 1994 tag ::= 1* text ::= 1*TEXT_CHAR text_mime2 ::= "=?" "?" "?" "?=" ;; Syntax defined in [MIME-2] TEXT_CHAR ::= time ::= 2digit ":" 2digit ":" 2digit ;; Hours minutes seconds uid ::= "UID" SPACE (copy / fetch / search / store) ;; Unique identifiers used instead of message ;; sequence numbers uniqueid ::= nz_number ;; Strictly ascending unsubscribe ::= ("UNSUBSCRIBE" SPACE mailbox) / unsubscribe_obs unsubscribe_obs ::= "UNSUBSCRIBE" SPACE "MAILBOX" SPACE mailbox ;;OBSOLETE userid ::= astring x_command ::= "X" atom zone ::= ("+" / "-") 4digit ;; Signed four-digit value of hhmm representing ;; hours and minutes west 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 [Page 62] RFC 1730 IMAP4 December 1994 zone_old ::= "UT" / "GMT" / "Z" / ;; +0000 "AST" / "EDT" / ;; -0400 "EST" / "CDT" / ;; -0500 "CST" / "MDT" / ;; -0600 "MST" / "PDT" / ;; -0700 "PST" / "YDT" / ;; -0800 "YST" / "HDT" / ;; -0900 "HST" / "BDT" / ;; -1000 "BST" / ;; -1100 "A" / "B" / "C" / "D" / "E" / "F" / ;; +1 to +6 "G" / "H" / "I" / "K" / "L" / "M" / ;; +7 to +12 "N" / "O" / "P" / "Q" / "R" / "S" / ;; -1 to -6 "T" / "U" / "V" / "W" / "X" / "Y" ;; -7 to -12 ;; OBSOLETE Crispin [Page 63] RFC 1730 IMAP4 December 1994 10. Author's Note This document is a revision or rewrite of earlier documents, and supercedes the protocol specification in those documents: IMAP4 Internet drafts, the IMAP2bis Internet drafts, unpublished IMAP2bis.TXT document, RFC 1176, and RFC 1064. 11. Security Considerations IMAP4 protocol transactions, including electronic mail data, are sent in the clear over the network unless the optional privacy protection is negotiated in the AUTHENTICATE command. 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 instead. A server error message for a failing LOGIN command should not specify that the user name, as opposed to the password, is invalid. Additional security considerations are discussed in the section discussing the AUTHENTICATE and LOGIN commands. 12. Author's Address Mark R. Crispin Networks and Distributed Computing, JE-30 University of Washington Seattle, WA 98195 Phone: (206) 543-5762 EMail: MRC@CAC.Washington.EDU Crispin [Page 64] RFC 1730 IMAP4 December 1994 Appendices A. Obsolete Commands The following commands are OBSOLETE. It is NOT required to support any of these commands in new server implementations. These commands are documented here for the benefit of implementors who may wish to support them for compatibility with old client implementations. The section headings of these commands are intended to correspond with where they would be located in the main document if they were not obsoleted. A.6.3.OBS.1. FIND ALL.MAILBOXES Command Arguments: mailbox name with possible wildcards Data: untagged responses: MAILBOX Result: OK - find completed NO - find failure: can't list that name BAD - command unknown or arguments invalid The FIND ALL.MAILBOXES command returns a subset of names from the complete set of all names available to the user. It returns zero or more untagged MAILBOX replies. The mailbox argument to FIND ALL.MAILBOXES is similar to that for LIST with an empty reference, except that the characters "%" and "?" match a single character. Example: C: A002 FIND ALL.MAILBOXES * S: * MAILBOX blurdybloop S: * MAILBOX INBOX S: A002 OK FIND ALL.MAILBOXES completed A.6.3.OBS.2. FIND MAILBOXES Command Arguments: mailbox name with possible wildcards Data: untagged responses: MAILBOX Result: OK - find completed NO - find failure: can't list that name BAD - command unknown or arguments invalid The FIND MAILBOXES command returns a subset of names from the set of names that the user has declared as being "active" or Crispin [Page 65] RFC 1730 IMAP4 December 1994 "subscribed". It returns zero or more untagged MAILBOX replies. The mailbox argument to FIND MAILBOXES is similar to that for LSUB with an empty reference, except that the characters "%" and "?" match a single character. Example: C: A002 FIND MAILBOXES * S: * MAILBOX blurdybloop S: * MAILBOX INBOX S: A002 OK FIND MAILBOXES completed A.6.3.OBS.3. SUBSCRIBE MAILBOX Command Arguments: mailbox name Data: no specific data for this command Result: OK - subscribe completed NO - subscribe failure: can't subscribe to that name BAD - command unknown or arguments invalid The SUBSCRIBE MAILBOX command is identical in effect to the SUBSCRIBE command. A server which implements this command must be able to distinguish between a SUBSCRIBE MAILBOX command and a SUBSCRIBE command with a mailbox name argument of "MAILBOX". Example: C: A002 SUBSCRIBE MAILBOX #news.comp.mail.mime S: A002 OK SUBSCRIBE MAILBOX to #news.comp.mail.mime completed C: A003 SUBSCRIBE MAILBOX S: A003 OK SUBSCRIBE to MAILBOX completed A.6.3.OBS.4. UNSUBSCRIBE MAILBOX Command Arguments: mailbox name Data: no specific data for this command Result: OK - unsubscribe completed NO - unsubscribe failure: can't unsubscribe that name BAD - command unknown or arguments invalid The UNSUBSCRIBE MAILBOX command is identical in effect to the UNSUBSCRIBE command. A server which implements this command must be able to distinguish between a UNSUBSCRIBE MAILBOX command and an UNSUBSCRIBE command with a mailbox name argument of "MAILBOX". Crispin [Page 66] RFC 1730 IMAP4 December 1994 Example: C: A002 UNSUBSCRIBE MAILBOX #news.comp.mail.mime S: A002 OK UNSUBSCRIBE MAILBOX from #news.comp.mail.mime completed C: A003 UNSUBSCRIBE MAILBOX S: A003 OK UNSUBSCRIBE from MAILBOX completed Crispin [Page 67] RFC 1730 IMAP4 December 1994 B. Obsolete Responses The following responses are OBSOLETE. Except as noted below, these responses MUST NOT be transmitted by new server implementations. The section headings of these responses are intended to correspond with where they would be located in the main document if they were not obsoleted. B.7.2.OBS.1. MAILBOX Response Data: name The MAILBOX response MUST NOT be transmitted by server implementations except in response to the obsolete FIND MAILBOXES and FIND ALL.MAILBOXES commands. Client implementations that do not use these commands MAY ignore this response. It is documented here for the benefit of implementors who may wish to support it for compatibility with old client implementations. This response occurs as a result of the FIND MAILBOXES and FIND ALL.MAILBOXES commands. It returns a single name that matches the FIND specification. There are no attributes or hierarchy delimiter. Example: S: * MAILBOX blurdybloop B.7.3.OBS.1. COPY Response Data: none The COPY response MUST NOT be transmitted by new server implementations. Client implementations MUST ignore the COPY response. It is documented here for the benefit of client implementors who may encounter this response from old server implementations. In some experimental versions of this protocol, this response was returned in response to a COPY command to indicate on a per-message basis that the message was copied successfully. Example: S: * 44 COPY Crispin [Page 68] RFC 1730 IMAP4 December 1994 B.7.3.OBS.2. STORE Response Data: message data The STORE response MUST NOT be transmitted by new server implementations. Client implementations MUST treat the STORE response as equivalent to the FETCH response. It is documented here for the benefit of client implementors who may encounter this response from old server implementations. In some experimental versions of this protocol, this response was returned instead of FETCH in response to a STORE command to report the new value of the flags. Example: S: * 69 STORE (FLAGS (\Deleted)) Crispin [Page 69] RFC 1730 IMAP4 December 1994 C. References [IMAP-AUTH] Myers, J., "IMAP4 Authentication Mechanism", RFC 1731. Carnegie-Mellon University, December 1994. [IMAP-COMPAT] Crispin, M. "IMAP4 Compatibility with IMAP2 and IMAP2bis", RFC 1732, University of Washington, December 1994. [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, University of Washington, December 1994. [IMAP-NAMING] Crispin, M. "Mailbox Naming Convention in IMAP4", Work in Progress. [IMAP2] Crispin, M., "Interactive Mail Access Protocol - Version 2", RFC 1176, University of Washington, August 1990. [IMSP] Myers, J. "IMSP -- Internet Message Support Protocol", Work in Progress. [MIME-1] Borenstein, N., and Freed, N., "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies", RFC 1521, Bellcore, Innosoft, September 1993. [MIME-2] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part Two: Message Header Extensions for Non-ASCII Text", RFC 1522, University of Tennessee, September 1993. [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, University of Delaware, August 1982. [SMTP] Postel, Jonathan B. "Simple Mail Transfer Protocol", STD 10, RFC 821, USC/Information Sciences Institute, August 1982. Crispin [Page 70] RFC 1730 IMAP4 December 1994 E. IMAP4 Keyword Index +FLAGS (store command data item) ............... 34 +FLAGS.SILENT (store command data item) ........ 34 -FLAGS (store command data item) ............... 34 -FLAGS.SILENT (store command data item) ........ 34 ALERT (response code) ...................................... 39 ALL (fetch item) ........................................... 29 ALL (search key) ........................................... 27 ANSWERED (search key) ...................................... 27 APPEND (command) ........................................... 22 AUTHENTICATE (command) ..................................... 12 BAD (response) ............................................. 41 BCC (search key) .................................. 27 BEFORE (search key) ................................. 27 BODY (fetch item) .......................................... 29 BODY (fetch result) ........................................ 46 BODY (search key) ................................. 27 BODY.PEEK[

] (fetch item) .......................... 30 BODYSTRUCTURE (fetch item) ................................. 31 BODYSTRUCTURE (fetch result) ............................... 47 BODY[

] (fetch item) ............................... 29 BODY[section] (fetch result) ............................... 46 BYE (response) ............................................. 41 CAPABILITY (command) ....................................... 10 CAPABILITY (response) ...................................... 42 CC (search key) ................................... 27 CHECK (command) ............................................ 23 CLOSE (command) ............................................ 24 COPY (command) ............................................. 34 COPY (response) ............................................ 68 CREATE (command) ........................................... 17 DELETE (command) ........................................... 18 DELETED (search key) ....................................... 27 DRAFT (search key) ......................................... 27 ENVELOPE (fetch item) ...................................... 31 ENVELOPE (fetch result) .................................... 49 EXAMINE (command) .......................................... 16 EXISTS (response) .......................................... 45 EXPUNGE (command) .......................................... 25 EXPUNGE (response) ......................................... 45 FAST (fetch item) .......................................... 31 FETCH (command) ............................................ 29 FETCH (response) ........................................... 46 FIND ALL.MAILBOXES (command) ............................... 65 FIND MAILBOXES (command) ................................... 65 FLAGGED (search key) ....................................... 27 FLAGS (fetch item) ......................................... 31 Crispin [Page 71] RFC 1730 IMAP4 December 1994 FLAGS (fetch result) ....................................... 50 FLAGS (response) ........................................... 44 FLAGS (store command data item) ................ 34 FLAGS.SILENT (store command data item) ......... 34 FROM (search key) ................................. 27 FULL (fetch item) .......................................... 31 HEADER (search key) .................. 27 INTERNALDATE (fetch item) .................................. 31 INTERNALDATE (fetch result) ................................ 50 KEYWORD (search key) ................................ 27 LARGER (search key) .................................... 27 LIST (command) ............................................. 20 LIST (response) ............................................ 43 LOGIN (command) ............................................ 14 LOGOUT (command) ........................................... 11 LSUB (command) ............................................. 22 LSUB (response) ............................................ 44 MAILBOX (response) ......................................... 68 NEW (search key) ........................................... 27 NO (response) .............................................. 40 NOOP (command) ............................................. 11 NOT (search key) .............................. 28 OK (response) .............................................. 40 OLD (search key) ........................................... 28 ON (search key) ..................................... 28 OR

(search key) ................ 28 PARSE (response code) ...................................... 39 PARTIAL (command) .......................................... 32 PERMANENTFLAGS (response code) ............................. 39 PREAUTH (response) ......................................... 41 READ-ONLY (response code) .................................. 39 READ-WRITE (response code) ................................. 39 RECENT (response) .......................................... 45 RECENT (search key) ........................................ 28 RENAME (command) ........................................... 18 RFC822 (fetch item) ........................................ 31 RFC822 (fetch result) ...................................... 50 RFC822.HEADER (fetch item) ................................. 31 RFC822.HEADER (fetch result) ............................... 50 RFC822.HEADER.LINES (fetch item) ............. 31 RFC822.HEADER.LINES.NOT (fetch item) ......... 32 RFC822.PEEK (fetch item) ................................... 31 RFC822.SIZE (fetch item) ................................... 32 RFC822.SIZE (fetch result) ................................. 50 RFC822.TEXT (fetch item) ................................... 32 RFC822.TEXT (fetch result) ................................. 51 RFC822.TEXT.PEEK (fetch item) .............................. 32 SEARCH (command) ........................................... 25 Crispin [Page 72] RFC 1730 IMAP4 December 1994 SEARCH (response) .......................................... 44 SEEN (search key) .......................................... 28 SELECT (command) ........................................... 15 SENTBEFORE (search key) ............................. 28 SENTON (search key) ................................. 28 SENTSINCE (search key) .............................. 28 SINCE (search key) .................................. 28 SMALLER (search key) ................................... 28 STORE (command) ............................................ 33 STORE (response) ........................................... 69 SUBJECT (search key) .............................. 28 SUBSCRIBE (command) ........................................ 19 SUBSCRIBE MAILBOX (command) ................................ 66 TEXT (search key) ................................. 28 TO (search key) ................................... 28 TRYCREATE (response code) .................................. 39 UID (command) .............................................. 35 UID (fetch item) ........................................... 32 UID (fetch result) ......................................... 51 UID (search key) ............................. 28 UIDVALIDITY (response code) ................................ 40 UNANSWERED (search key) .................................... 29 UNDELETED (search key) ..................................... 29 UNDRAFT (search key) ....................................... 29 UNFLAGGED (search key) ..................................... 29 UNKEYWORD (search key) .............................. 29 UNSEEN (response code) ..................................... 40 UNSEEN (search key) ........................................ 29 UNSUBSCRIBE (command) ...................................... 19 UNSUBSCRIBE MAILBOX (command) .............................. 66 X (command) .......................................... 37 \Answered (system flag) .................................... 50 \Deleted (system flag) ..................................... 50 \Draft (system flag) ....................................... 50 \Flagged (system flag) ..................................... 50 \Marked (mailbox name attribute) ........................... 43 \Noinferiors (mailbox name attribute) ...................... 43 \Noselect (mailbox name attribute) ......................... 43 \Recent (system flag) ...................................... 50 \Seen (system flag) ........................................ 50 \Unmarked (mailbox name attribute) ......................... 43 Crispin [Page 73]