draft-josefsson-dns-url-12.txt		draft-josefsson-dns-url.txt
	Network Working Group S. Josefsson		Network Working Group S. Josefsson
	Expires: November 26, 2005		Expires: February 6, 2006
	Domain Name System Uniform Resource Identifiers		Domain Name System Uniform Resource Identifiers
	draft-josefsson-dns-url-12		draft-josefsson-dns-url-13
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
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	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 33		skipping to change at page 1, line 33
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
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	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on November 26, 2005.		This Internet-Draft will expire on February 6, 2006.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2005).		Copyright (C) The Internet Society (2005).
	Abstract		Abstract
	This document define Uniform Resource Identifiers for Domain Name		This document define Uniform Resource Identifiers for Domain Name
	System resources.		System resources.
	skipping to change at page 2, line 26		skipping to change at page 2, line 26
	9.1 Normative References . . . . . . . . . . . . . . . . . . . 10		9.1 Normative References . . . . . . . . . . . . . . . . . . . 10
	9.2 Informative References . . . . . . . . . . . . . . . . . . 10		9.2 Informative References . . . . . . . . . . . . . . . . . . 10
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . 11		Author's Address . . . . . . . . . . . . . . . . . . . . . . . 11
	A. Revision Changes . . . . . . . . . . . . . . . . . . . . . . . 11		A. Revision Changes . . . . . . . . . . . . . . . . . . . . . . . 11
	A.1 Changes since -06 . . . . . . . . . . . . . . . . . . . . 11		A.1 Changes since -06 . . . . . . . . . . . . . . . . . . . . 11
	A.2 Changes since -07 . . . . . . . . . . . . . . . . . . . . 12		A.2 Changes since -07 . . . . . . . . . . . . . . . . . . . . 12
	A.3 Changes since -08 . . . . . . . . . . . . . . . . . . . . 12		A.3 Changes since -08 . . . . . . . . . . . . . . . . . . . . 12
	A.4 Changes since -09 . . . . . . . . . . . . . . . . . . . . 12		A.4 Changes since -09 . . . . . . . . . . . . . . . . . . . . 12
	A.5 Changes since -10 . . . . . . . . . . . . . . . . . . . . 12		A.5 Changes since -10 . . . . . . . . . . . . . . . . . . . . 12
	A.6 Changes since -11 . . . . . . . . . . . . . . . . . . . . 12		A.6 Changes since -11 . . . . . . . . . . . . . . . . . . . . 12
	Intellectual Property and Copyright Statements . . . . . . . . 13		A.7 Changes since -12 . . . . . . . . . . . . . . . . . . . . 13
			Intellectual Property and Copyright Statements . . . . . . . . 14
	1. Introduction and Background		1. Introduction and Background
	The Domain Name System (DNS) [1] [2] is a widely deployed system used		The Domain Name System (DNS) [1] [2] is a widely deployed system used
	to, among other things, translate host names into IP addresses.		to, among other things, translate host names into IP addresses.
	Recent work has added support for storing certificates and		Several protocols are using Uniform Resource Identifier (URI) to
	certificate revocation lists (CRLs) in the DNS [9]. Several		refer to data. By defining a URI scheme for DNS data, the gap
	protocols use Uniform Resource Locators (URLs) to point at		between these two worlds are bridged. The DNS URI scheme defined
	certificates and CRLs. By defining a Uniform Resource Identifier		here can be used to reference any data stored in the DNS.
	(URI) scheme for DNS resources, such protocols can reference
	certificates and CRLs stored in the DNS.
	Two examples of data structures that may embed DNS URIs:
	o The OpenPGP Message Format [7], where an end-user may indicate the
	location of a copy of any updates to her key, using the "preferred
	key server" field.
	o The Internet X.509 Public Key Infrastructure [14] format, where
	the issuer may use a DNS URI in a CRL Distribution Point
	certificate extension field.
	The DNS URI scheme defined here can be used to reference any data
	stored in the DNS, and is not limited to certificates or CRLs. The
	purpose of this specification is to define a generic DNS URI, not to
	specify a solution only for certificates stored in the DNS.
	Data browsers may support DNS URIs by forming DNS queries and render		Data browsers may support DNS URIs by forming DNS queries and render
	DNS responses using HTML [13], similar to what is commonly done for		DNS responses using HTML [14], similar to what is commonly done for
	FTP [6] resources.		FTP [6] resources. Applications that are Multipurpose Internet Mail
			Extension (MIME) [7] aware may tag DNS data retrieve using this
			scheme with the text/dns or application/dns types as specified in
			[18].
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [3].		document are to be interpreted as described in RFC 2119 [3].
	2. Usage Model		2. Usage Model
	The reader is referred to section 1 of [5] for an in-depth discussion		The reader is referred to section 1 of [5] for an in-depth discussion
	of URI classifications. In particular, the reader is assumed to be		of URI classifications. In particular, the reader is assumed to be
	familiar with the "name" vs "locator" distinction. This section		familiar with the "name" vs "locator" distinction. This section
	skipping to change at page 5, line 8		skipping to change at page 5, line 8
	certain applications, a more detailed URI syntax that map more		certain applications, a more detailed URI syntax that map more
	closely to the DNS protocol may be required. However, such an URI		closely to the DNS protocol may be required. However, such an URI
	definition is not included in this document. This document specify a		definition is not included in this document. This document specify a
	URI that is primarily intended to name DNS resources, but it can also		URI that is primarily intended to name DNS resources, but it can also
	be used to locate said resources for simple (but common)		be used to locate said resources for simple (but common)
	applications.		applications.
	3. DNS URI Registration		3. DNS URI Registration
	The section contain the registration template for the DNS URI scheme		The section contain the registration template for the DNS URI scheme
	in accordance with [12].		in accordance with [13].
	URL scheme name: "dns".		URL scheme name: "dns".
	URL scheme syntax: A DNS URI designate a DNS resource record set,		URL scheme syntax: A DNS URI designate a DNS resource record set,
	referenced by domain name, class, type and optionally the authority.		referenced by domain name, class, type and optionally the authority.
	The DNS URI follows the generic syntax from RFC 3986 [5], and is		The DNS URI follows the generic syntax from RFC 3986 [5], and is
	described using ABNF [4]. Strings are not case sensitive and free		described using ABNF [4]. Strings are not case sensitive and free
	insertion of linear-white-space is not permitted.		insertion of linear-white-space is not permitted.
	dnsurl = "dns:" [ "//" dnsauthority "/" ]		dnsurl = "dns:" [ "//" dnsauthority "/" ]
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	interoperability impact though.		interoperability impact though.
	Interoperability problems may occur if one entity understands a new		Interoperability problems may occur if one entity understands a new
	DNS class/type mnemonic and another entity do not understand it.		DNS class/type mnemonic and another entity do not understand it.
	This is an interoperability problem for DNS software in general,		This is an interoperability problem for DNS software in general,
	although it is not a major practical problem as the DNS types and		although it is not a major practical problem as the DNS types and
	classes are fairly static. To guarantee interoperability		classes are fairly static. To guarantee interoperability
	implementations can use integers for all mnemonics not defined in		implementations can use integers for all mnemonics not defined in
	[2].		[2].
	Interaction with Binary Labels [11], or other extended label types,		Interaction with Binary Labels [12], or other extended label types,
	has not been analyzed. However, they appear to be infrequently used		has not been analyzed. However, they appear to be infrequently used
	in practice.		in practice.
	Contact: simon@josefsson.org		Contact: simon@josefsson.org
	Author/Change Controller: simon@josefsson.org		Author/Change Controller: simon@josefsson.org
	4. Examples		4. Examples
	A DNS URI is of the following general form. This is intended to		A DNS URI is of the following general form. This is intended to
	illustrate, not define, the scheme.		illustrate, not define, the scheme.
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	If a DNS URI references domains in the Internet DNS environment, both		If a DNS URI references domains in the Internet DNS environment, both
	the URI itself and the information referenced by the URI is public		the URI itself and the information referenced by the URI is public
	information. If a DNS URI is used within an "internal" DNS		information. If a DNS URI is used within an "internal" DNS
	environment, both the DNS URI and the data is referenced should be		environment, both the DNS URI and the data is referenced should be
	handled using the same considerations that apply to DNS data in the		handled using the same considerations that apply to DNS data in the
	environment.		environment.
	If information referenced by DNS URIs are used to make security		If information referenced by DNS URIs are used to make security
	decisions (examples of such data include, but is not limited to,		decisions (examples of such data include, but is not limited to,
	certificates stored in the DNS), implementations may need to employ		certificates stored in the DNS [10]), implementations may need to
	security techniques such as Secure DNS [8], or even CMS [15] or		employ security techniques such as Secure DNS [9], or even CMS [15]
	OpenPGP [7], to protect the data during transport. How to implement		or OpenPGP [8], to protect the data during transport. How to
	this will depend on the usage scenario, and it is not up to this URI		implement this will depend on the usage scenario, and it is not up to
	scheme to define how the data referenced by DNS URIs should be		this URI scheme to define how the data referenced by DNS URIs should
	protected.		be protected.
	If applications accept unknown dnsqueryelement values (e.g., accepts		If applications accept unknown dnsqueryelement values (e.g., accepts
	the URI "dns:www.example.org?secret=value" without knowing what the		the URI "dns:www.example.org?secret=value" without knowing what the
	"secret=value" dnsqueryelement means), a covert channel used to		"secret=value" dnsqueryelement means), a covert channel used to
	"leak" information may be enabled. The implications of covert		"leak" information may be enabled. The implications of covert
	channels should be understood by applications that accepts unknown		channels should be understood by applications that accepts unknown
	dnsqueryelement values.		dnsqueryelement values.
	Slight variations, such as difference between upper and lower case in		Slight variations, such as difference between upper and lower case in
	the dnsname field, can be used as a covert channel to leak		the dnsname field, can be used as a covert channel to leak
	information.		information.
	7. IANA Considerations		7. IANA Considerations
	The IANA is asked to register the DNS URI scheme, using the template		The IANA is asked to register the DNS URI scheme, using the template
	in section 3, in accordance with RFC 2717 [12].		in section 3, in accordance with RFC 2717 [13].
	8. Copying conditions		8. Copying conditions
	Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005 Simon Josefsson		Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005 Simon Josefsson
	Regarding this entire document or any portion of it, the author makes		Regarding this entire document or any portion of it, the author makes
	no guarantees and is not responsible for any damage resulting from		no guarantees and is not responsible for any damage resulting from
	its use. The author grants irrevocable permission to anyone to use,		its use. The author grants irrevocable permission to anyone to use,
	modify, and distribute it in any way that does not diminish the		modify, and distribute it in any way that does not diminish the
	rights of anyone else to use, modify, and distribute it, provided		rights of anyone else to use, modify, and distribute it, provided
	skipping to change at page 10, line 43		skipping to change at page 10, line 43
	[5] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform		[5] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
	Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,		Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
	January 2005.		January 2005.
	9.2 Informative References		9.2 Informative References
	[6] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9,		[6] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9,
	RFC 959, October 1985.		RFC 959, October 1985.
	[7] Callas, J., Donnerhacke, L., Finney, H., and R. Thayer,		[7] Freed, N., Klensin, J., and J. Postel, "Multipurpose Internet
			Mail Extensions (MIME) Part Four: Registration Procedures",
			BCP 13, RFC 2048, November 1996.
			[8] Callas, J., Donnerhacke, L., Finney, H., and R. Thayer,
	"OpenPGP Message Format", RFC 2440, November 1998.		"OpenPGP Message Format", RFC 2440, November 1998.
	[8] Eastlake, D., "Domain Name System Security Extensions",		[9] Eastlake, D., "Domain Name System Security Extensions",
	RFC 2535, March 1999.		RFC 2535, March 1999.
	[9] Eastlake, D. and O. Gudmundsson, "Storing Certificates in the		[10] Eastlake, D. and O. Gudmundsson, "Storing Certificates in the
	Domain Name System (DNS)", RFC 2538, March 1999.		Domain Name System (DNS)", RFC 2538, March 1999.
	[10] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams,		[11] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams,
	"X.509 Internet Public Key Infrastructure Online Certificate		"X.509 Internet Public Key Infrastructure Online Certificate
	Status Protocol - OCSP", RFC 2560, June 1999.		Status Protocol - OCSP", RFC 2560, June 1999.
	[11] Crawford, M., "Binary Labels in the Domain Name System",		[12] Crawford, M., "Binary Labels in the Domain Name System",
	RFC 2673, August 1999.		RFC 2673, August 1999.
	[12] Petke, R. and I. King, "Registration Procedures for URL Scheme		[13] Petke, R. and I. King, "Registration Procedures for URL Scheme
	Names", BCP 35, RFC 2717, November 1999.		Names", BCP 35, RFC 2717, November 1999.
	[13] Connolly, D. and L. Masinter, "The 'text/html' Media Type",		[14] Connolly, D. and L. Masinter, "The 'text/html' Media Type",
	RFC 2854, June 2000.		RFC 2854, June 2000.
	[14] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509
	Public Key Infrastructure Certificate and Certificate
	Revocation List (CRL) Profile", RFC 3280, April 2002.
	[15] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3369,		[15] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3369,
	August 2002.		August 2002.
	[16] Faltstrom, P., Hoffman, P., and A. Costello,		[16] Faltstrom, P., Hoffman, P., and A. Costello,
	"Internationalizing Domain Names in Applications (IDNA)",		"Internationalizing Domain Names in Applications (IDNA)",
	RFC 3490, March 2003.		RFC 3490, March 2003.
	[17] Yergeau, F., "UTF-8, a transformation format of ISO 10646",		[17] Yergeau, F., "UTF-8, a transformation format of ISO 10646",
	STD 63, RFC 3629, November 2003.		STD 63, RFC 3629, November 2003.
			[18] Josefsson, S., "Domain Name System Media Types", RFC 4027,
			April 2005.
	Author's Address		Author's Address
	Simon Josefsson		Simon Josefsson
	Email: simon@josefsson.org		Email: simon@josefsson.org
	Appendix A. Revision Changes		Appendix A. Revision Changes
	Note to RFC editor: Remove this appendix before publication.		Note to RFC editor: Remove this appendix before publication.
	skipping to change at page 13, line 5		skipping to change at page 13, line 5
	Add section "Usage Model". Move acknowledgements, as per rfc2223bis.		Add section "Usage Model". Move acknowledgements, as per rfc2223bis.
	Add permissive copying condition. Updates to align with RFC 3986.		Add permissive copying condition. Updates to align with RFC 3986.
	A.6 Changes since -11		A.6 Changes since -11
	Fix typos. IESG feedback: Move RFC2119 reference to normative		Fix typos. IESG feedback: Move RFC2119 reference to normative
	section. Replace OCSP example with X.509 CRL Distribution Point		section. Replace OCSP example with X.509 CRL Distribution Point
	extension. Fix ABNF not to use "...".		extension. Fix ABNF not to use "...".
			A.7 Changes since -12
			Reference MIME and RFC 4027. IESG feedback: Do not mention OpenPGP/
			X.509 as illustrative examples in the introduction section.
	Intellectual Property Statement		Intellectual Property Statement
	The IETF takes no position regarding the validity or scope of any		The IETF takes no position regarding the validity or scope of any
	Intellectual Property Rights or other rights that might be claimed to		Intellectual Property Rights or other rights that might be claimed to
	pertain to the implementation or use of the technology described in		pertain to the implementation or use of the technology described in
	this document or the extent to which any license under such rights		this document or the extent to which any license under such rights
	might or might not be available; nor does it represent that it has		might or might not be available; nor does it represent that it has
	made any independent effort to identify any such rights. Information		made any independent effort to identify any such rights. Information
	on the procedures with respect to rights in RFC documents can be		on the procedures with respect to rights in RFC documents can be
	found in BCP 78 and BCP 79.		found in BCP 78 and BCP 79.
End of changes.
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