draft-josefsson-dns-url-09.txt		draft-josefsson-dns-url-10.txt
	Network Working Group S. Josefsson		Network Working Group S. Josefsson
	Expires: April 25, 2004		Expires: March 3, 2005
	Domain Name System Uniform Resource Identifiers		Domain Name System Uniform Resource Identifiers
	draft-josefsson-dns-url-09		draft-josefsson-dns-url-10
	Status of this Memo		Status of this Memo
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	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2003). All Rights Reserved.		Copyright (C) The Internet Society (2004).
	Abstract		Abstract
	This document define Uniform Resource Identifiers for Domain Name		This document define Uniform Resource Identifiers for Domain Name
	System resources.		System resources.
	Table of Contents		Table of Contents
	1. Introduction and Background . . . . . . . . . . . . . . . . . 3		1. Introduction and Background . . . . . . . . . . . . . . . . . 3
	2. DNS URI Registration . . . . . . . . . . . . . . . . . . . . . 4		2. DNS URI Registration . . . . . . . . . . . . . . . . . . . . . 4
	3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 7		3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 8		4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
	Normative References . . . . . . . . . . . . . . . . . . . . . 9		6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
	Informative References . . . . . . . . . . . . . . . . . . . . 9		6.1 Normative References . . . . . . . . . . . . . . . . . . . . 9
			6.2 Informative References . . . . . . . . . . . . . . . . . . . 9
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . 10		Author's Address . . . . . . . . . . . . . . . . . . . . . . . 10
	A. Revision Changes . . . . . . . . . . . . . . . . . . . . . . . 10		A. Revision Changes . . . . . . . . . . . . . . . . . . . . . . . 10
	A.1 Changes since -06 . . . . . . . . . . . . . . . . . . . . . . 10		A.1 Changes since -06 . . . . . . . . . . . . . . . . . . . . 10
	A.2 Changes since -07 . . . . . . . . . . . . . . . . . . . . . . 10		A.2 Changes since -07 . . . . . . . . . . . . . . . . . . . . 10
	A.3 Changes since -08 . . . . . . . . . . . . . . . . . . . . . . 10		A.3 Changes since -08 . . . . . . . . . . . . . . . . . . . . 11
			A.4 Changes since -09 . . . . . . . . . . . . . . . . . . . . 11
	Intellectual Property and Copyright Statements . . . . . . . . 12		Intellectual Property and Copyright Statements . . . . . . . . 12
	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		Recent work has added support for storing certificates and
	certificate revocation lists in the DNS [10].		certificate revocation lists (CRLs) in the DNS [9]. Several
			protocols use Uniform Resource Locators (URLs) to point at
	The primary motivation behind defining a Uniform Resource Identifier		certificates and CRLs. By defining a Uniform Resource Identifier
	(URI) for DNS resources, instead of using another non-URI syntax that		(URI) scheme for DNS resources, such protocols can reference
	embed the domain, type value and class value, is that applications		certificates and CRLs stored in the DNS.
	that stores or retrieve certificates today uses URIs for this
	purpose. Thus, defining a URI scheme for DNS resources allows these
	existing protocols to be used with certificates in the DNS without
	having to add DNS specific modifications to said protocols. In order
	to not introduce interoperability or security considerations,
	protocols that uses these URIs naturally must have been written to
	allow for future, as of writing yet undefined, URIs to be used.
	A few examples of protocols that may utilize DNS URIs:		A few examples of protocols that may utilize DNS URIs:
	o The OpenPGP Message Format [8], where an end-user may indicate the		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		location of a copy of any updates to her key, using the "preferred
	key server" field.		key server" field.
	o The X.509 Online Certificate Status Protocol [11], where the OCSP		o The X.509 Online Certificate Status Protocol [10], where the OCSP
	responder can indicate where a CRL is found, using the		responder can indicate where a CRL is found, using the
	id-pkix-ocsp-crl extension.		id-pkix-ocsp-crl extension.
	The DNS URI scheme defined here can, of course, be used to reference		The DNS URI scheme defined here can be used to reference any data
	any DNS data, and is not limited to only certificates. The purpose		stored in the DNS, and is not limited to certificates or CRLs. The
	of this specification is to define a generic DNS URI, not a specific		purpose of this specification is to define a generic DNS URI, not to
	DNS solution for certificates stored in the DNS. Browsers may		specify a solution only for certificates stored in the DNS.
	implement support for DNS URIs by forming DNS queries and render DNS
	responses using HTML [14], similar to what is done for the FTP [5].
	The core part of this document is the URI Registration Template		Data browsers may support DNS URIs by forming DNS queries and render
	according to [13].		DNS responses using HTML [13], similar to what is commonly done for
			FTP [5] resources.
			The core part of this document is the URI Registration Template in
			accordance with [12].
	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 [6].		document are to be interpreted as described in RFC 2119 [6].
	2. DNS URI Registration		2. DNS URI Registration
	URL scheme name: "dns".		URL scheme name: "dns".
	URL scheme syntax: A DNS URI designates a DNS resource record set		URL scheme syntax: A DNS URI designate a DNS resource record set,
	that can be referenced by domain name, type, class and optionally the		referenced by domain name, class, type and optionally the authority.
	authority. The DNS URI follows the generic syntax from RFC 2396 [4],		The DNS URI follows the generic syntax from RFC 2396 [4], and is
	and is described using ABNF [3]. Strings are not case sensitive and		described using ABNF [3]. Strings are not case sensitive and free
	free insertion of linear-white-space is not permitted.		insertion of linear-white-space is not permitted.
	dnsurl = "dns:" [ "//" dnsauthority "/" ] dnsname ["?" dnsquery]		dnsurl = "dns:" [ "//" dnsauthority "/" ] dnsname ["?" dnsquery]
	dnsauthority = hostport		dnsauthority = hostport
	; See RFC 2396 for "hostport" definition.		; See RFC 2396 for "hostport" definition.
	dnsname = *pchar		dnsname = *pchar
	; See RFC 2396 for "pchar" definition.		; See RFC 2396 for "pchar" definition.
	; NB! Can be empty.
			; The "dnsname" field may be a "relative"
			; or "absolute" name, as per RFC 1034
			; section 3.1.
			; Note further that an empty "dnsname"
			; value is to be interpreted as the
			; root itself. See below on relative
			; dnsname's.
	dnsquery = dnsqueryelement [";" dnsquery]		dnsquery = dnsqueryelement [";" dnsquery]
	; First matching element MUST be used.
	; E.g., dns:host.example.org?TYPE=A;TYPE=TXT
	; means type A.
	dnsqueryelement = ( "CLASS=" dnsclassval ) / ( "TYPE=" dnstypeval ) /		dnsqueryelement = ( "CLASS=" dnsclassval ) / ( "TYPE=" dnstypeval )
	( 1*alphanum "=" 1*alphanum )		; Each clause MUST NOT be used more than
			; once.
	dnsclassval = 1*digit / "IN" / "CH" / ...		dnsclassval = 1*digit / "IN" / "CH" / ...
	; Any IANA registered DNS class expressed as		; Any IANA registered DNS class expressed
	; mnemonic or as decimal integer.		; as mnemonic or as decimal integer.
	dnstypeval = 1*digit / "A" / "NS" / "MD" / ...		dnstypeval = 1*digit / "A" / "NS" / "MD" / ...
	; Any IANA registered DNS type expressed as		; Any IANA registered DNS type expressed
	; mnemonic or as decimal integer.		; as mnemonic or as decimal integer.
			Unless specified in the URI, the authority ("dnsauthority") is
			assumed to be locally known, the class ("dnsclassval") to be the
			Internet class ("IN"), and the type ("dnstypeval") to be the Address
			type ("A"). These default values match the typical use of DNS; to
			look up addresses for host names.
			A dnsquery element MUST NOT contain more than one occurance of the
			"CLASS" and "TYPE" fields. For example, both
			"dns:example?TYPE=A;TYPE=TXT" and "dns:example?TYPE=A;TYPE=A" are
			invalid. However, the fields may occur in any order, so that both
			"dns:example?TYPE=A;CLASS=IN" and "dns:example?CLASS=IN;TYPE=A" are
			valid.
	The digit representation of types and classes MAY be used when a		The digit representation of types and classes MAY be used when a
	mnemonic for the corresponding value is not well known (e.g., for		mnemonic for the corresponding value is not well known (e.g., for
	newly introduced types or classes), but SHOULD NOT be used for the		newly introduced types or classes), but SHOULD NOT be used for the
	types or classes defined in the DNS specification [2]. All		types or classes defined in the DNS specification [2]. All
	implementations MUST recognize the mnemonics defined in [2].		implementations MUST recognize the mnemonics defined in [2].
	Unless specified in the URI, the authority ("dnsauthority") is		To avoid ambiguity, relative "dnsname" values (i.e., those not ending
	assumed to be locally known, "dnsclassval" to be the Internet class		with ".") are assumed to be relative to the root. For example,
	("IN"), and "dnstypeval" to be the Address type ("A").		"dns:host.example" and "dns:host.example." both refer to the same
			owner name, namely "host.example.". Further, an empty "dnsname"
			value is considered to be a degenerative form of a relative name,
			which refer to the root (".").
	To resolve a DNS URI using the DNS protocol [2] a query is formed by		To resolve a DNS URI using the DNS protocol [2] a query is created,
	using the dnsname, dnsclassval and dnstypeval from the URI string (or		using as input the dnsname, dnsclassval and dnstypeval from the URI
	the previously mentioned default values if some value missing from		string (or the appropriate default values). If an authority
	the string). If authority ("dnsauthority") is given in the URI		("dnsauthority") is given in the URI string, this indicate the server
	string, this indicate the server that should receive the DNS query,		that should receive the DNS query, otherwise the default DNS server
	otherwise the default DNS server should receive it. (Note that DNS		should receive it.
	URIs could be resolved by other protocols than the DNS protocol. DNS
	URIs does not require the use of the DNS protocol, although it is		Note that DNS URIs could be resolved by other protocols than the DNS
	expected to be the typical usage. This paragraph only illustrate how		protocol, or by using the DNS protocol in some other way than as
	DNS URIs are resolved using the DNS protocol.)		described above (e.g., multicast DNS). DNS URIs do not require the
			use of the DNS protocol, although it is expected to be the typical
			usage. The previous paragraph only illustrate how DNS URIs are
			resolved using the DNS protocol.
	A client MAY want to check that it understands the dnsclassval and		A client MAY want to check that it understands the dnsclassval and
	dnstypeval before sending a query, so that it is able to correctly		dnstypeval before sending a query, so that it will be able to
	parse the answer. A typical example of a client that would not need		understand the response. However, a typical example of a client that
	to check dnsclassval and dnstypeval would be a proxy that just treat		would not need to check dnsclassval and dnstypeval would be a proxy,
	the answer as opaque data.		that would just treat the received answer as opaque data.
	Character encoding considerations: The characters are encoded as per		Character encoding considerations: The characters are encoded as per
	the "URI Generic Syntax" RFC [4]. The DNS protocol do not consider		the "URI Generic Syntax" RFC [4]. The DNS protocol do not consider
	character sets, it simply transports opaque data. In particular, the		character sets, it simply transports opaque data. In particular, the
	"dnsname" field of the DNS URI is to be considered an		"dnsname" field of the DNS URI is to be considered an
	internationalized domain name (IDN) unaware domain name slot, in the		internationalized domain name (IDN) unaware domain name slot, in the
	terminology of [16]. (The reason for this is that making these fields		terminology of [15]. The considerations for "hostport" are discussed
	be IDN aware by, e.g., specifying that they are UTF-8 [7] strings,		in [4]
	would require further encoding mechanisms to be able to express all
	valid DNS domain names. This is because the DNS allows all octet
	sequences to be used as domain labels, so UTF-8 strings do not cover
	all possibilities. Instead of defining further encoding mechanisms,
	we point applications with internationalization needs at the ASCII
	encoding described in [16] which should be satisfactory.) The
	considerations for "hostport" are discussed in [4]
	To encode a "." that is part of a DNS label the "escaped" encoding		Because "." is used as the DNS label separator, an escaping mechanism
	MUST be used, and a label delimiter MUST be encoded as ".". That is,		is required to encode a "." that is part of a DNS label. The
	the only way to encode a label delimiter is ".", and the only way to		escaping mechanism is described in section 5.1 of RFC 1035. For
	encode a "." as part of label is "%2e". This approach was chosen to		example, a DNS label of "exa.mple" can be escaped as "exa\.mple" or
	minimize the modifications users will have to do when manually		"exa\046mple". However, the URI specification disallow the "\"
	translating a domain name string into the URI form.		character from occuring directly in URIs, so it must be escaped as
			"%5c". The single DNS label "exa.mple" is thus encoded as
			"exa%5c.mple". The same mechanism can be used to encode other
			characters, for example "?" and ";". Note that "." and "%2e" are
			equivalent within dnsname, and are interchangable.
	This URI specification allows all possible domain names to be encoded		This URI specification allows all possible domain names to be encoded
	(of course following the encoding rules of [4]), however certain		(of course following the encoding rules of [4]), however certain
	applications may restrict the set of valid characters and care should		applications may restrict the set of valid characters and care should
	be taken so that invalid characters in these contexts does not cause		be taken so that invalid characters in these contexts does not cause
	harm. In particular, host names in the DNS have certain		harm. In particular, host names in the DNS have certain
	restrictions. It is up to these application to limit this subset,		restrictions. It is up to these application to limit this subset,
	this URI scheme places no restrictions.		this URI scheme places no restrictions.
	Intended usage: Whenever DNS resources are useful to reference by		Intended usage: Whenever DNS resources are useful to reference by
	protocol independent identifiers, often when the data is more		protocol independent identifiers, often when the data is more
	important than the access method. Since software in general has		important than the access method. Since software in general has
	coped without this so far, it is not anticipated to be implemented		coped without this so far, it is not anticipated to be implemented
	widely, nor migrated to by existing systems, but specific solutions		widely, nor migrated to by existing systems, but specific solutions
	(especially security related) may find this appropriate.		(especially security related) may find this appropriate.
	Applications and/or protocols which use this scheme: Security related		Applications and/or protocols which use this scheme: Security related
	software. It may be of interest to auxilliary DNS related software		software. DNS administration tools. Network programming packages.
	too.
	Interoperability considerations: The data referenced by this URI		Interoperability considerations: The data referenced by this URI
	scheme might be transferred by protocols that are not URI aware (such		scheme might be transferred by protocols that are not URI aware (such
	as the DNS protocol). This is not anticipated to have any serious		as the DNS protocol). This is not anticipated to have any serious
	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 type or class mnemonic but 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 could use integers for all mnemonics not defined in		implementations can use integers for all mnemonics not defined in
	[2].		[2].
	Interaction with Binary Labels [12], or other extended label types,		Interaction with Binary Labels [11], 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.
	Security considerations: See below.
	Contact: simon@josefsson.org		Contact: simon@josefsson.org
	Author/Change Controller: simon@josefsson.org		Author/Change Controller: simon@josefsson.org
	3. Examples		3. 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.
	dns:[//authority/]domain[?type=TYPE;class=CLASS]		dns:[//authority/]domain[?CLASS=class;TYPE=type]
	The following illustrate a URI for a resource with the name		The following illustrate a URI for a resource with the absolute name
	"www.example.org", the Internet (IN) class and the Address (A) type:		"www.example.org.", the Internet (IN) class and the Address (A) type:
	dns:www.example.org?class=IN;type=A		dns:www.example.org.?clAsS=IN;tYpE=A
	Since the default class is IN, and the default type is A, the same		Since the default class is IN, and the default type is A, the same
	resource can be identified by a shorter URI:		resource can be identified by a shorter URI, using a relative name:
	dns:www.example.org		dns:www.example.org
	The following illustrate a URI for a resource with the name		The following illustrate a URI for a resource with the name
	"simon.example.org", for the CERT type, in the Internet (IN) class:		"simon.example.org", for the CERT type, in the Internet (IN) class:
	dns:simon.example.org?type=CERT		dns:simon.example.org?type=CERT
	The following illustrate a URI for a resource with the name		The following illustrate a URI for a resource with the name
	"ftp.example.org", in the Internet (IN) class and the address (A)		"ftp.example.org", in the Internet (IN) class and the address (A)
	type, but from the DNS authority 192.168.1.1 instead of the default		type, but from the DNS authority 192.168.1.1 instead of the default
	authority (i.e., when DNS is used, the query is sent to that server):		authority:
	dns://192.168.1.1/ftp.example.org?type=A		dns://192.168.1.1/ftp.example.org?type=A
	The following illustrate a strange, albeit valid, DNS resource. Note		The following illustrate various escaping techniques. The owner name
	the encoding of "." and 0x00, and the use of a named dnsauthority:		would be "world wide web.example\.domain.org" where "\." denote the
			character "." as part of a label, and "." denote the label separator:
	dns://internal-dns.example.org/*.%3f%20%00%2e%25+?type=TXT		dns:world%20wide%20web.example%5c.domain.example?TYPE=TXT
			The following illustrate a strange, but valid, DNS resource:
			dns://fw.example.org/*.%20%00.example?type=TXT
	4. Security Considerations		4. Security Considerations
	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), implementations may need to employ
	security techniques such as Secure DNS [9], or even CMS [15] or		security techniques such as Secure DNS [8], or even CMS [14] or
	OpenPGP [8], to protect the data during transport. How to implement		OpenPGP [7], to protect the data during transport. How to implement
	this will depend on the usage scenario, and it is not up to this URI		this will depend on the usage scenario, and it is not up to this URI
	scheme to define how the data referenced by DNS URIs should be		scheme to define how the data referenced by DNS URIs should be
	protected.		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.
	This draft does not modify the security considerations related to the		Slight variations, such as difference between upper and lower case in
	DNS or URIs in general.		the dnsname field, can be used as a covert channel to leak
			information.
	5. IANA Considerations		5. 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 2, in accordance with RFC 2717 [13].		in section 2, in accordance with RFC 2717 [12].
	Acknowledgments		Acknowledgments
	Thanks to Stuart Cheshire, Donald Eastlake, Pasi Eronen, Ted Hardie,		Thanks to Stuart Cheshire, Donald Eastlake, Pasi Eronen, Ted Hardie,
	Peter Koch, Andrew Main, Larry Masinter, Michael Mealling, Steve		Peter Koch, Andrew Main, Larry Masinter, Michael Mealling, Steve
	Mattson, and Paul Vixie for comments and suggestions. The author		Mattson, and Paul Vixie for comments and suggestions. The author
	acknowledges the RSA Laboratories for supporting the work that led to		acknowledges the RSA Laboratories for supporting the work that led to
	this document.		this document.
	Normative References		6. References
			6.1 Normative References
	[1] Mockapetris, P., "Domain names - concepts and facilities", STD		[1] Mockapetris, P., "Domain names - concepts and facilities", STD
	13, RFC 1034, November 1987.		13, RFC 1034, November 1987.
	[2] Mockapetris, P., "Domain names - implementation and		[2] Mockapetris, P., "Domain names - implementation and
	specification", STD 13, RFC 1035, November 1987.		specification", STD 13, RFC 1035, November 1987.
	[3] Crocker, D. and P. Overell, "Augmented BNF for Syntax		[3] Crocker, D. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", RFC 2234, November 1997.		Specifications: ABNF", RFC 2234, November 1997.
	[4] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource		[4] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource
	Identifiers (URI): Generic Syntax", RFC 2396, August 1998.		Identifiers (URI): Generic Syntax", RFC 2396, August 1998.
	Informative References		6.2 Informative References
	[5] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9,		[5] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9,
	RFC 959, October 1985.		RFC 959, October 1985.
	[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement		[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement
	Levels", BCP 14, RFC 2119, March 1997.		Levels", BCP 14, RFC 2119, March 1997.
	[7] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC		[7] Callas, J., Donnerhacke, L., Finney, H. and R. Thayer, "OpenPGP
	2279, January 1998.
	[8] Callas, J., Donnerhacke, L., Finney, H. and R. Thayer, "OpenPGP
	Message Format", RFC 2440, November 1998.		Message Format", RFC 2440, November 1998.
	[9] Eastlake, D., "Domain Name System Security Extensions", RFC		[8] Eastlake, D., "Domain Name System Security Extensions", RFC
	2535, March 1999.		2535, March 1999.
	[10] Eastlake, D. and O. Gudmundsson, "Storing Certificates in the		[9] 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.
	[11] Myers, M., Ankney, R., Malpani, A., Galperin, S. and C. Adams,		[10] 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.
	[12] Crawford, M., "Binary Labels in the Domain Name System", RFC		[11] Crawford, M., "Binary Labels in the Domain Name System", RFC
	2673, August 1999.		2673, August 1999.
	[13] Petke, R. and I. King, "Registration Procedures for URL Scheme		[12] Petke, R. and I. King, "Registration Procedures for URL Scheme
	Names", BCP 35, RFC 2717, November 1999.		Names", BCP 35, RFC 2717, November 1999.
	[14] Connolly, D. and L. Masinter, "The 'text/html' Media Type", RFC		[13] Connolly, D. and L. Masinter, "The 'text/html' Media Type", RFC
	2854, June 2000.		2854, June 2000.
	[15] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3369,		[14] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3369,
	August 2002.		August 2002.
	[16] Faltstrom, P., Hoffman, P. and A. Costello, "Internationalizing		[15] Faltstrom, P., Hoffman, P. and A. Costello, "Internationalizing
	Domain Names in Applications (IDNA)", RFC 3490, March 2003.		Domain Names in Applications (IDNA)", RFC 3490, March 2003.
			[16] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD
			63, RFC 3629, November 2003.
	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: This appendix is to be removed on publication.		Note to RFC editor: Remove this appendix before publication.
	A.1 Changes since -06		A.1 Changes since -06
	The MIME registration templates for text/dns and application/dns was		The MIME registration templates for text/dns and application/dns was
	removed, and will be defined in separate documents.		removed, and will be defined in separate documents.
	Improved discussion related to which mnemonics that must be		Improved discussion related to which mnemonics that must be
	supported. The interoperability problem that provoked the		supported. The interoperability problem that provoked the
	clarification is also mentioned.		clarification is also mentioned.
	skipping to change at page 11, line 8		skipping to change at page 11, line 14
	A.3 Changes since -08		A.3 Changes since -08
	Modifications derived from Last-Call comments: Made more clear that		Modifications derived from Last-Call comments: Made more clear that
	DNS URIs does not imply use of the DNS protocol, but the issue is not		DNS URIs does not imply use of the DNS protocol, but the issue is not
	stressed because of the apparent inflamatory state of affairs. Added		stressed because of the apparent inflamatory state of affairs. Added
	informative references to HTML and FTP. Clarified that dnsname can		informative references to HTML and FTP. Clarified that dnsname can
	be empty. Clarified that first dnsqueryelement "win" in case of		be empty. Clarified that first dnsqueryelement "win" in case of
	ambiguity. Clarified security consideration with respect to unknown		ambiguity. Clarified security consideration with respect to unknown
	dnsqueryelements. Use "authority" instead of "server". Say "IANA		dnsqueryelements. Use "authority" instead of "server". Say "IANA
	registered" instead of "standard". Interoperability note about binary		registered" instead of "standard". Interoperability note about
	DNS labels. Typos.		binary DNS labels. Typos.
			A.4 Changes since -09
			Use legal texts from RFC 3667. Update UTF-8 reference to RFC 3629.
			Simplified introduction. Discuss relative and absolute dnsname's.
			Clarify that empty dnsname correspond to the root. Change so that
			dns:foo?TYPE=A;TYPE=TXT is invalid, instead of meaning TYPE=A. The
			underspecified extension mechanism was dropped; now only TYPE= and
			CLASS= are permitted. Remove background discussion of why the
			dnsname field is made a IDN unaware domain name slot. Use standard
			DNS escaping (i.e, "\." for ".") instead of broken approach that
			violated the URI specification. Improve examples. Add security
			considerations.
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End of changes.
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