< draft-gahrns-imap-namespace-04.txt		draft-gahrns-imap-namespace-05.txt >
	Network Working Group M. Gahrns, Microsoft		Network Working Group M. Gahrns, Microsoft
	C. Newman, Innosoft		C. Newman, Innosoft
	Internet Draft		Internet Draft
	Document: draft-gahrns-imap-namespace-04.txt October 1997		Document: draft-gahrns-imap-namespace-05.txt November 1997
	IMAP4 Namespace		IMAP4 Namespace
	Status of this Memo		Status of this Memo
	This document is an Internet Draft. Internet Drafts are working		This document is an Internet Draft. Internet Drafts are working
	documents of the Internet Engineering Task Force (IETF), its Areas,		documents of the Internet Engineering Task Force (IETF), its Areas,
	and its Working Groups. Note that other groups may also distribute		and its Working Groups. Note that other groups may also distribute
	working documents as Internet Drafts.		working documents as Internet Drafts.
	skipping to change at line 30 ¶		skipping to change at line 30 ¶
	"working draft" or "work in progress".		"working draft" or "work in progress".
	To learn the current status of any Internet-Draft, please check the		To learn the current status of any Internet-Draft, please check the
	1id-abstracts.txt listing contained in the Internet-Drafts Shadow		1id-abstracts.txt listing contained in the Internet-Drafts Shadow
	Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or		Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or
	munnari.oz.au.		munnari.oz.au.
	A revised version of this draft document will be submitted to the		A revised version of this draft document will be submitted to the
	RFC editor as a Proposed Standard for the Internet Community.		RFC editor as a Proposed Standard for the Internet Community.
	Discussion and suggestions for improvement are requested. This		Discussion and suggestions for improvement are requested. This
	document will expire before May 1997. Distribution of this draft is		document will expire before June 1997. Distribution of this draft is
	unlimited.		unlimited.
	1. Abstract		1. Abstract
	IMAP4[RFC-2060] does not define a default server namespace. As a		IMAP4[RFC-2060] does not define a default server namespace. As a
	result, two common namespace models have evolved:		result, two common namespace models have evolved:
	The 'Personal Mailbox' model, in which the default namespace that is		The "Personal Mailbox" model, in which the default namespace that is
	presented consists of only the user's personal mailboxes. To access		presented consists of only the user's personal mailboxes. To access
	shared mailboxes, the user must use an escape mechanism to reach		shared mailboxes, the user must use an escape mechanism to reach
	another namespace.		another namespace.
	The 'Complete Hierarchy' model, in which the default namespace that		The "Complete Hierarchy" model, in which the default namespace that
	is presented includes the user's personal mailboxes along with any		is presented includes the user's personal mailboxes along with any
	other mailboxes they have access to.		other mailboxes they have access to.
	These two models, create difficulties for certain client operations.		These two models, create difficulties for certain client operations.
	This document defines a NAMESPACE command that allows a client to		This document defines a NAMESPACE command that allows a client to
	discover the prefixes of namespaces used by a server for personal		discover the prefixes of namespaces used by a server for personal
	mailboxes, other users' mailboxes, and shared mailboxes. This		mailboxes, other users' mailboxes, and shared mailboxes. This
	allows a client to avoid much of the manual user configuration that		allows a client to avoid much of the manual user configuration that
	is now necessary when mixing and matching IMAP4 clients and servers.		is now necessary when mixing and matching IMAP4 clients and servers.
	Gahrns and Newman 1		Gahrns and Newman 1
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	2. Conventions used in this document		2. Conventions used in this document
	In examples, "C:" and "S:" indicate lines sent by the client and		In examples, "C:" and "S:" indicate lines sent by the client and
	server respectively.		server respectively.
	Personal Namespace: A namespace that the server considers within the		Personal Namespace: A namespace that the server considers within the
	personal scope of the authenticated user on a particular connection.		personal scope of the authenticated user on a particular connection.
	Typically, only the authenticated user has access to mailboxes in		Typically, only the authenticated user has access to mailboxes in
	their Personal Namespace. It is the part of the namespace that		their Personal Namespace. It is the part of the namespace that
	skipping to change at line 109 ¶		skipping to change at line 109 ¶
	In addition, users are often required to manually enter the prefixes		In addition, users are often required to manually enter the prefixes
	of various namespaces in order to view the mailboxes located there.		of various namespaces in order to view the mailboxes located there.
	For example, they might be required to enter the prefix of #shared		For example, they might be required to enter the prefix of #shared
	to view the shared mailboxes namespace. The NAMESPACE command allows		to view the shared mailboxes namespace. The NAMESPACE command allows
	a client to automatically discover the namespaces that are available		a client to automatically discover the namespaces that are available
	on a server. This allows a client to present the available		on a server. This allows a client to present the available
	namespaces to the user in what ever manner it deems appropriate.		namespaces to the user in what ever manner it deems appropriate.
	Gahrns and Newman 2		Gahrns and Newman 2
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	For example, a client could choose to initially display only		For example, a client could choose to initially display only
	personal mailboxes, or it may choose to display the complete list of		personal mailboxes, or it may choose to display the complete list of
	mailboxes available, and initially position the user at the root of		mailboxes available, and initially position the user at the root of
	their Personal Namespace.		their Personal Namespace.
	A server MAY choose to make available to the NAMESPACE command only		A server MAY choose to make available to the NAMESPACE command only
	a subset of the complete set of namespaces the server supports. To		a subset of the complete set of namespaces the server supports. To
	provide the ability to access these namespaces, a client SHOULD		provide the ability to access these namespaces, a client SHOULD
	allow the user the ability to manually enter a namespace prefix.		allow the user the ability to manually enter a namespace prefix.
	skipping to change at line 137 ¶		skipping to change at line 137 ¶
	state.		state.
	5. NAMESPACE Command		5. NAMESPACE Command
	Arguments: none		Arguments: none
	Response: an untagged NAMESPACE response that contains the prefix		Response: an untagged NAMESPACE response that contains the prefix
	and hierarchy delimiter to the server's Personal		and hierarchy delimiter to the server's Personal
	Namespace(s), Other Users' Namespace(s), and Shared		Namespace(s), Other Users' Namespace(s), and Shared
	Namespace(s) that the server wishes to expose. The		Namespace(s) that the server wishes to expose. The
	response will contain a NIL for any namespace that is not		response will contain a NIL for any namespace class that
	available. Namespace_Response_Extensions MAY be included		is not available. Namespace_Response_Extensions MAY be
	in the response. Namespace_Response_Extensions which are		included in the response. Namespace_Response_Extensions
	not on the IETF standards track, MUST be prefixed with an		which are not on the IETF standards track, MUST be
	"X-".		prefixed with an "X-".
	Result: OK - Command completed		Result: OK - Command completed
	NO - Error: Can't complete command		NO - Error: Can't complete command
	BAD - argument invalid		BAD - argument invalid
	Example 5.1:		Example 5.1:
	===========		===========
	< A server that supports a single personal namespace. No leading		< A server that supports a single personal namespace. No leading
	prefix is used on personal mailboxes and "/" is the hierarchy		prefix is used on personal mailboxes and "/" is the hierarchy
	delimiter.>		delimiter.>
	C: A001 NAMESPACE		C: A001 NAMESPACE
	S: * NAMESPACE (("" "/")) NIL NIL		S: * NAMESPACE (("" "/")) NIL NIL
	S: A001 OK NAMESPACE command completed		S: A001 OK NAMESPACE command completed
	Gahrns and Newman 3		Gahrns and Newman 3
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	Example 5.2:		Example 5.2:
	===========		===========
	< A user logged on anonymously to a server. No personal		< A user logged on anonymously to a server. No personal
	mailboxes are associated with the anonymous user and the user		mailboxes are associated with the anonymous user and the user
	does not have access to the Other Users' Namespace. No prefix is		does not have access to the Other Users' Namespace. No prefix is
	required to access shared mailboxes and the hierarchy delimiter		required to access shared mailboxes and the hierarchy delimiter
	is "." >		is "." >
	skipping to change at line 194 ¶		skipping to change at line 194 ¶
	Example 5.4:		Example 5.4:
	===========		===========
	< A server that contains a Personal Namespace, Other Users'		< A server that contains a Personal Namespace, Other Users'
	Namespace and multiple Shared Namespaces. Note that the		Namespace and multiple Shared Namespaces. Note that the
	hierarchy delimiter used within each namespace can be		hierarchy delimiter used within each namespace can be
	different. >		different. >
	C: A001 NAMESPACE		C: A001 NAMESPACE
	S: * NAMESPACE (("" "/")) (("~" "/")) (("#shared/" "/")		S: * NAMESPACE (("" "/")) (("~" "/")) (("#shared/" "/")
	("#public/" "/") ("#ftp/" "/") ("#news." "."))		("#public/" "/")("#ftp/" "/")("#news." "."))
	S: A001 OK NAMESPACE command completed		S: A001 OK NAMESPACE command completed
	The prefix string allows a client to do things such as automatically		The prefix string allows a client to do things such as automatically
	creating personal mailboxes or LISTing all available mailboxes		creating personal mailboxes or LISTing all available mailboxes
	within a namespace.		within a namespace.
	Example 5.5:		Example 5.5:
	===========		===========
	< A server that supports only the Personal Namespace, with a		< A server that supports only the Personal Namespace, with a
	leading prefix of INBOX to personal mailboxes and a hierarchy		leading prefix of INBOX to personal mailboxes and a hierarchy
	delimiter of ".">		delimiter of ".">
	Gahrns and Newman 4		Gahrns and Newman 4
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	C: A001 NAMESPACE		C: A001 NAMESPACE
	S: * NAMESPACE (("INBOX." ".")) NIL NIL		S: * NAMESPACE (("INBOX." ".")) NIL NIL
	S: A001 OK NAMESPACE command completed		S: A001 OK NAMESPACE command completed
	< Automatically create a mailbox to store sent items.>		< Automatically create a mailbox to store sent items.>
	C: A002 CREATE "INBOX.Sent Mail"		C: A002 CREATE "INBOX.Sent Mail"
	S: A002 OK CREATE command completed		S: A002 OK CREATE command completed
	skipping to change at line 246 ¶		skipping to change at line 246 ¶
	< The client is configured to save a copy of all mail sent by the		< The client is configured to save a copy of all mail sent by the
	user into a mailbox called 'Sent Mail'. Furthermore, after a		user into a mailbox called 'Sent Mail'. Furthermore, after a
	message is deleted from a mailbox, the client is configured to		message is deleted from a mailbox, the client is configured to
	move that message to a mailbox called 'Deleted Items'.>		move that message to a mailbox called 'Deleted Items'.>
	< Note that this example demonstrates how some extension flags		< Note that this example demonstrates how some extension flags
	can be passed to further describe the #mh namespace. >		can be passed to further describe the #mh namespace. >
	C: A001 NAMESPACE		C: A001 NAMESPACE
	S: * NAMESPACE (("" "/") ("#mh/" "/" X-PARAM (FLAG1 FLAG2))) NIL		S: * NAMESPACE (("" "/")("#mh/" "/" "X-PARAM" ("FLAG1" "FLAG2")))
	NIL		NIL NIL
	S: A001 OK NAMESPACE command completed		S: A001 OK NAMESPACE command completed
	< It is desired to keep only one copy of sent mail. It is unclear		< It is desired to keep only one copy of sent mail. It is unclear
	which Personal Namespace the client should use to create the		which Personal Namespace the client should use to create the
	'Sent Mail' mailbox. The user is prompted to select a namespace		'Sent Mail' mailbox. The user is prompted to select a namespace
	and only one 'Sent Mail' mailbox is created. >		and only one 'Sent Mail' mailbox is created. >
	C: A002 CREATE "Sent Mail"		C: A002 CREATE "Sent Mail"
	S: A002 OK CREATE command completed		S: A002 OK CREATE command completed
	< The client is designed so that it keeps two 'Deleted Items'		< The client is designed so that it keeps two 'Deleted Items'
	mailboxes, one for each namespace. >		mailboxes, one for each namespace. >
	C: A003 CREATE "Delete Items"		C: A003 CREATE "Delete Items"
	S: A003 OK CREATE command completed
	Gahrns and Newman 5		Gahrns and Newman 5
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			S: A003 OK CREATE command completed
	C: A004 CREATE "#mh/Deleted Items"		C: A004 CREATE "#mh/Deleted Items"
	S: A004 OK CREATE command completed		S: A004 OK CREATE command completed
	The next level of hierarchy following the Other Users' Namespace		The next level of hierarchy following the Other Users' Namespace
	prefix SHOULD consist of <username>, where <username> is a user name		prefix SHOULD consist of <username>, where <username> is a user name
	as per the IMAP4 LOGIN or AUTHENTICATE command.		as per the IMAP4 LOGIN or AUTHENTICATE command.
	A client can construct a LIST command by appending a "%" to the		A client can construct a LIST command by appending a "%" to the
	Other Users' Namespace prefix to discover the Personal Namespaces of		Other Users' Namespace prefix to discover the Personal Namespaces of
	skipping to change at line 314 ¶		skipping to change at line 315 ¶
	S: A002 OK LIST command completed		S: A002 OK LIST command completed
	Example 5.8:		Example 5.8:
	===========		===========
	< A server that does not support providing a list of other user's		< A server that does not support providing a list of other user's
	mailboxes that are accessible to the currently logged on user.		mailboxes that are accessible to the currently logged on user.
	The mailboxes are listable if the client includes the name of the		The mailboxes are listable if the client includes the name of the
	other user with the Other Users' Namespace prefix. >		other user with the Other Users' Namespace prefix. >
	C: A001 NAMESPACE
	Gahrns and Newman 6		Gahrns and Newman 6
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			C: A001 NAMESPACE
	S: * NAMESPACE (("" "/")) (("#Users/" "/")) NIL		S: * NAMESPACE (("" "/")) (("#Users/" "/")) NIL
	S: A001 OK NAMESPACE command completed		S: A001 OK NAMESPACE command completed
	< In this example, the currently logged on user has access to the		< In this example, the currently logged on user has access to the
	Personal Namespace of user Mike, but the server chose to suppress		Personal Namespace of user Mike, but the server chose to suppress
	this information in the LIST response. However, by appending the		this information in the LIST response. However, by appending the
	user name Mike (received through user input) to the Other Users'		user name Mike (received through user input) to the Other Users'
	Namespace prefix, the client is able to get a listing of the		Namespace prefix, the client is able to get a listing of the
	personal mailboxes of user Mike. >		personal mailboxes of user Mike. >
	skipping to change at line 367 ¶		skipping to change at line 367 ¶
	S: A002 OK LIST command completed		S: A002 OK LIST command completed
	Historical convention has been to start all namespaces with the "#"		Historical convention has been to start all namespaces with the "#"
	character. Namespaces that include the "#" character are not IMAP		character. Namespaces that include the "#" character are not IMAP
	URL [IMAP-URL] friendly requiring the "#" character to be		URL [IMAP-URL] friendly requiring the "#" character to be
	represented as %23 when within URLs. As such, server implementers		represented as %23 when within URLs. As such, server implementers
	MAY instead consider using namespace prefixes that do not contain		MAY instead consider using namespace prefixes that do not contain
	the "#" character.		the "#" character.
	Gahrns and Newman 7		Gahrns and Newman 7
	IMAP4 Namespace October 1997		IMAP4 Namespace November 1997
	6. Formal Syntax		6. Formal Syntax
	The following syntax specification uses the augmented Backus-Naur		The following syntax specification uses the augmented Backus-Naur
	Form (BNF) as described in [ABNF].		Form (BNF) as described in [ABNF].
	atom = <atom>		atom = <atom>
	; <atom> as defined in [RFC-2060]		; <atom> as defined in [RFC-2060]
	Namespace = nil / "(" 1*( "(" string SP (<"> QUOTED_CHAR <"> /		Namespace = nil / "(" 1*( "(" string SP (<"> QUOTED_CHAR <"> /
	nil) *(Namespace_Response_Extension) ")" ) ")"		nil) *(Namespace_Response_Extension) ")" ) ")"
	Namespace_Command = "NAMESPACE"		Namespace_Command = "NAMESPACE"
	Namespace_Response_Extension = SP atom SP "(" string *(SP string)		Namespace_Response_Extension = SP string SP "(" string *(SP string)
	")"		")"
	Namespace_Response = "*" SP "NAMESPACE" SP Namespace SP Namespace SP		Namespace_Response = "*" SP "NAMESPACE" SP Namespace SP Namespace SP
	Namespace		Namespace
	; The first Namespace is the Personal Namespace(s)		; The first Namespace is the Personal Namespace(s)
	; The second Namespace is the Other Users' Namespace(s)		; The second Namespace is the Other Users' Namespace(s)
	; The third Namespace is the Shared Namespace(s)		; The third Namespace is the Shared Namespace(s)
	nil = <nil>		nil = <nil>
	; <nil> as defined in [RFC-2060]		; <nil> as defined in [RFC-2060]
	QUOTED_CHAR = <QUOTED_CHAR>		QUOTED_CHAR = <QUOTED_CHAR>
	; <QUOTED_CHAR> as defined in [RFC-2060]		; <QUOTED_CHAR> as defined in [RFC-2060]
	string = <string>		string = <string>
	; <string> as defined in [RFC-2060]		; <string> as defined in [RFC-2060]
			; Note that the namespace prefix is to a mailbox and following
			; IMAP4 convention, any international string in the NAMESPACE
			; response MUST be of modified UTF-7 format as described in
			; [RFC-2060].
	7. Security Considerations		7. Security Considerations
	In response to a LIST command containing an argument of the Other		In response to a LIST command containing an argument of the Other
	Users' Namespace prefix, a server SHOULD NOT list users that have		Users' Namespace prefix, a server SHOULD NOT list users that have
	not granted access to their personal mailboxes to the currently		not granted access to their personal mailboxes to the currently
	authenticated user. Providing such a list, could compromise		authenticated user. Providing such a list, could compromise
	security by potentially disclosing confidential information of who		security by potentially disclosing confidential information of who
	is located on the server, or providing a starting point of a list of		is located on the server, or providing a starting point of a list of
	user accounts to attack.		user accounts to attack.
	8. References		8. References
	[RFC-2060], Crispin, M., "Internet Message Access Protocol – Version		[RFC-2060], Crispin, M., "Internet Message Access Protocol – Version
	4rev1", RFC 2060, University of Washington, December 1996.		4rev1", RFC 2060, University of Washington, December 1996.
			Gahrns and Newman 8
			IMAP4 Namespace November 1997
	[RFC-2119], Bradner, S, "Key words for use in RFCs to Indicate		[RFC-2119], Bradner, S, "Key words for use in RFCs to Indicate
	Requirement Levels", RFC 2119, Harvard University, March 1997		Requirement Levels", RFC 2119, Harvard University, March 1997
	Gahrns and Newman 8
	IMAP4 Namespace October 1997
	[ABNF], DRUMS working group, Dave Crocker Editor, "Augmented BNF for		[ABNF], DRUMS working group, Dave Crocker Editor, "Augmented BNF for
	Syntax Specifications: ABNF", draft-drums-abnf-04.txt (work in		Syntax Specifications: ABNF", draft-drums-abnf-04.txt (work in
	progress), Internet Mail Consortium, September 1997		progress), Internet Mail Consortium, September 1997
	[IMAP-URL], Newman, C., "IMAP URL Scheme", RFC 2192, Innosoft,		[IMAP-URL], Newman, C., "IMAP URL Scheme", RFC 2192, Innosoft,
	September 1997		September 1997
	9. Acknowledgments		9. Acknowledgments
	Many people have participated in the discussion of IMAP namespaces		Many people have participated in the discussion of IMAP namespaces
End of changes. 22 change blocks.
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