< draft-ietf-dnsop-alt-tld-05.txt		draft-ietf-dnsop-alt-tld-06.txt >
	dnsop W. Kumari		dnsop W. Kumari
	Internet-Draft Google		Internet-Draft Google
	Intended status: Informational A. Sullivan		Intended status: Informational A. Sullivan
	Expires: March 16, 2017 Dyn		Expires: May 3, 2017 Dyn
	September 12, 2016		October 30, 2016
	The ALT Special Use Top Level Domain		The ALT Special Use Top Level Domain
	draft-ietf-dnsop-alt-tld-05		draft-ietf-dnsop-alt-tld-06
	Abstract		Abstract
	This document reserves a string (ALT) to be used as a TLD label in		This document reserves a string (ALT) to be used as a TLD label in
	non-DNS contexts or for names that have no meaning in a global		non-DNS contexts, or for names that have no meaning in a global
	context. It also provides advice and guidance to developers		context. It also provides advice and guidance to developers
	developing alternate namespaces.		developing alternate namespaces.
	[ Ed note: This document lives in GitHub at:		[ Ed note: This document lives in GitHub at:
	https://github.com/wkumari/draft-wkumari-dnsop-alt-tld . Issues and		https://github.com/wkumari/draft-wkumari-dnsop-alt-tld . Issues and
	pull requests happily accepted. ]		pull requests happily accepted. ]
	[ Question for Working Group. It has been proposed that the string
	.ALT should be replaced with something else e.g. .NOT-DNS. As naming
	discussions in the IETF are always short, simple, and not
	controversial, we figured we should open these for discussion now.
	We would appreciate clear feedback on preference and rationale. ]
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on March 16, 2017.		This Internet-Draft will expire on May 3, 2017.
	Copyright Notice		Copyright Notice
	Copyright (c) 2016 IETF Trust and the persons identified as the		Copyright (c) 2016 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3		1.1. Requirements notation . . . . . . . . . . . . . . . . . . 2
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. The ALT namespace . . . . . . . . . . . . . . . . . . . . . . 4		3. The ALT namespace . . . . . . . . . . . . . . . . . . . . . . 4
	3.1. Choice of the ALT Name . . . . . . . . . . . . . . . . . 5		3.1. Choice of the ALT Name . . . . . . . . . . . . . . . . . 5
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	4.1. Domain Name Reservation Considerations . . . . . . . . . 6		4.1. Domain Name Reservation Considerations . . . . . . . . . 5
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 7		5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
	7. Normative References . . . . . . . . . . . . . . . . . . . . 8		7. Normative References . . . . . . . . . . . . . . . . . . . . 6
	Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 8		Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	Many protocols and systems need to name entities. Names that look		Many protocols and systems need to name entities. Names that look
	like DNS names (a series of labels separated with dots) have become		like DNS names (a series of labels separated with dots) have become
	common, even in systems that are not part of the global DNS		common, even in systems that are not part of the global DNS
	administered by IANA.		administered by IANA.
	This document provides a solution that may, in many cases, be more
	appropriate than [RFC6761].
	This document reserves the label "ALT" (short for "Alternate") as a		This document reserves the label "ALT" (short for "Alternate") as a
	Special Use Domain ([RFC6761]). This label is intended to be used as		Special Use Domain ([RFC6761]). This label is intended to be used as
	the final (rightmost) label to signify that the name is not rooted in		the final (rightmost) label to signify that the name is not rooted in
	the DNS, and that normal registration and lookup rules do not apply.		the DNS, and that normal registration and lookup rules do not apply.
	1.1. Requirements notation		1.1. Requirements notation
	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 [RFC2119].		document are to be interpreted as described in [RFC2119].
	1.2. Terminology		1.2. Terminology
	This document assumes familiarity with DNS terms and concepts.		This document assumes familiarity with DNS terms and concepts.
	Please see [RFC1034] for background and concepts, and		Please see [RFC1034] for background and concepts, and [RFC7719] for
	[I-D.ietf-dnsop-dns-terminology] for terminology.		terminology. Readers are also expected to be familiar with the
			discussions in [I-D.tldr-sutld-ps]
	o DNS name: Domain names that are intended to be used with DNS		o DNS name: Domain names that are intended to be used with DNS
	resolution, either in the global DNS or in some other context		resolution, either in the global DNS or in some other context
	o DNS context: The namespace anchored at the globally-unique DNS		o DNS context: The namespace anchored at the globally-unique DNS
	root. This is the namespace or context that "normal" DNS uses.		root. This is the namespace or context that "normal" DNS uses.
	o non-DNS context: Any other (alternate) namespace.		o non-DNS context: Any other (alternate) namespace.
	o pseudo-TLD: A label that appears in a fully-qualified domain name		o pseudo-TLD: A label that appears in a fully-qualified domain name
	in the position of a TLD, but which is not registered in the		in the position of a TLD, but which is not registered in the
	global DNS.		global DNS. This term is in no way intended to be pejorative.
	o TLD: The last visible label in either a fully-qualified domain		o TLD: The last visible label in either a fully-qualified domain
	name or a name that is qualified relative to the root. See the		name or a name that is qualified relative to the root. See the
	discussion in Section 2.		discussion in Section 2.
	2. Background		2. Background
	The DNS data model is based on a tree structure, and has a single		The DNS data model is based on a tree structure, and has a single
	root. Conventionally, a name immediately beneath the root is called		root. Conventionally, a name immediately beneath the root is called
	a "Top Level Domain" or "TLD". TLDs usually delegate portions of		a "Top Level Domain" or "TLD". TLDs usually delegate portions of
	their namespace to others, who may then delegate further. The		their namespace to others, who may then delegate further. The
	hierarchical, distributed and caching nature of the DNS has made it		hierarchical, distributed and caching nature of the DNS has made it
	the primary resolution system on the Internet.		the primary resolution system on the Internet.
	Domain names are terminated by a zero-length label, so the root label
	is normally invisible. Truly fully-qualified names indicate the root
	label explicitly, thus: "an.example.tld.". Most of the time, names
	are written implicitly relative to the root, thus: "an.example.tld".
	In both of these cases, the TLD is the last label that is visible in
	presentation format -- in this example, the string "tld". (This
	little bit of pedantry is here because, in different contexts, people
	can use the term "fully-qualified domain name" to refer to either of
	these uses.) It is worth noting that the root label is present in
	the on-wire format of fully-qualified domain names, even if not
	displayed in the presentation form.
	The success of the DNS makes it a natural starting point for systems		The success of the DNS makes it a natural starting point for systems
	that need to name entities in a non-DNS context, or that have no		that need to name entities in a non-DNS context, or that have no
	unique meaning in a global context. These name resolutions,		unique meaning in a global context. These name resolutions occur in
	therefore, occur in a namespace distinct from the DNS.		a namespace distinct from the DNS.
	In many cases, these systems build a DNS-style tree parallel to, but		In many cases, these systems build a DNS-style tree parallel to, but
	separate from, the global DNS. They often use a pseudo-TLD to cause		separate from, the global DNS. They often use a pseudo-TLD to cause
	resolution in the alternate namespace, using browser plugins, shims		resolution in the alternate namespace, using browser plugins, shims
	in the name resolution process, or simply applications that perform		in the name resolution process, or simply applications that perform
	special handling of this particular alternate namespace.		special handling of this particular alternate namespace.
	In many cases, the creators of these alternate namespaces have chosen		In many cases, the creators of these alternate namespaces have chosen
	a convenient or descriptive string and started using it. These new		a convenient or descriptive string and started using it. These
	strings are "alternate" strings and are not registered anywhere or		strings are not registered anywhere nor are they part of the DNS.
	part of the DNS. However they appear to users and to some		However they appear to users and to some applications to be TLDs, and
	applications to be TLDs. Issues may arise if they are looked up in		issues may arise if they are looked up in the DNS.
	the DNS. These include:
	o User confusion: If someone emails a link of the form
	foo.bar.pseudo-TLD to someone who does not have the necessary
	software to resolve names in the pseudo-TLD namespace, the name
	will not resolve and the user may become confused.
	o Excess traffic hitting the DNS root: Lookups leak out of the
	pseudo-TLD namespace and end up hitting the DNS root nameservers.
	o Collisions: If the pseudo-TLD is eventually delegated from the
	root zone, the lookup behavior will change in a non-deterministic
	fashion.
	o Lack of success for the user's original goal.
	An alternate name resolution system might be specifically designed to		An alternate name resolution system might be specifically designed to
	provide confidentiality of the looked up name, and to provide a		provide confidentiality of the looked up name, and to provide a
	distributed and censorship-resistant namespace. This goal would		distributed and censorship-resistant namespace. This goal would
	necessarily be defeated if the queries leak into the DNS, because the		necessarily be defeated if the queries leak into the DNS, because the
	attempt to look up the name would be visible at least to the		attempt to look up the name would be visible at least to the
	operators of root name servers and to any entity viewing the DNS		operators of root name servers and to any entity viewing the DNS
	lookups going to the root nameservers.		lookups going to the root nameservers.
	3. The ALT namespace		3. The ALT namespace
	In order to avoid the above issues, we reserve the ALT label. Unless		This document reserves the ALT label, using the [RFC6761] process,
	the name desired is globally unique, has meaning on the global		for use as a pseudo-TLD. This creates an unmanaged sandbox
	context and is delegated in the DNS, it should be considered an		namespace. The ALT label MAY be used in any domain name as a pseudo-
	alternate namespace, and follow the ALT label scheme outlined below.		TLD to signify that this is an alternate (non-DNS) namespace.
	The ALT label MAY be used in any domain name as a pseudo-TLD to
	signify that this is an alternate (non-DNS) namespace.
	Alternate namespaces should differentiate themselves from other		Alternate namespaces should differentiate themselves from other
	alternate namespaces by choosing a name and using it in the label		alternate namespaces by choosing a name and using it in the label
	position just before the pseudo-TLD (ALT). For example, a group		position just before the pseudo-TLD (ALT). For example, a group
	wishing to create a namespace for Friends Of Olaf might choose the		wishing to create a namespace for Friends Of Olaf might choose the
	string "foo" and use any set of labels under foo.alt.		string "foo" and use any set of labels under foo.alt.
	As they are in an alternate namespace, they have no significance in		As they are in an alternate namespace, they have no significance in
	the regular DNS context and so should not be looked up in the DNS		the regular DNS context and so should not be looked up in the DNS
	context. Some of these requests will inevitably leak into the DNS		context. Some of these requests will inevitably leak into the DNS
	context (for example, because clicks on a link in a browser that does		context (for example, because of clicks on a link in a browser that
	not have a extension installed that implements the alternate		does not have a extension installed that implements the alternate
	namespace resolution), and so the ALT TLD has been added to the		namespace resolution), and so the ALT TLD has been added to the
	"Locally Served DNS Zones" ( [RFC6303]) registry to limit how far		"Locally Served DNS Zones" ( [RFC6303]) registry to limit how far
	these flow.		these flow.
	Groups wishing to create new alternate namespaces SHOULD create their		Groups wishing to create new alternate namespaces MAY create their
	alternate namespace under a label that names their namespace, and		alternate namespace under a label that names their namespace under
	under the ALT label. They SHOULD choose a label that they expect to		the ALT label. They SHOULD choose a label that they expect to be
	be unique and, ideally, descriptive. There is no IANA controlled		unique and, ideally, descriptive. There is no IANA controlled
	registry for names under the ALT TLD - it is an unmanaged namespace,		registry for names under the ALT TLD - it is an unmanaged namespace,
	and developers are responsible for dealing with any collisions that		and developers are responsible for dealing with any collisions that
	may occur under .alt. Informal lists of namespaces under .alt may		may occur under .alt. Informal lists of namespaces under .alt may
	appear to assist the developer community.		appear to assist the developer community.
	[Editor note (to be removed before publication): There was		[Editor note (to be removed before publication): There was
	significant discussion on an IANA registry for the ALT namespace -		significant discussion on an IANA registry for the ALT namespace -
	please consult the lists for full thread, but the consensus seems to		please consult the lists for full thread, but the consensus seems to
	be that it would be better for the IETF / IANA to not administer a		be that it would be better for the IETF / IANA to not administer a
	registry for this. It is expected one or more unofficial lists will		registry for this. It is expected one or more unofficial lists will
	skipping to change at page 6, line 5 ¶		skipping to change at page 5, line 14 ¶
	3.1. Choice of the ALT Name		3.1. Choice of the ALT Name
	A number of names other than "ALT" were considered and discarded. In		A number of names other than "ALT" were considered and discarded. In
	order for this technique to be effective the names need to continue		order for this technique to be effective the names need to continue
	to follow both the DNS format and conventions (a prime consideration		to follow both the DNS format and conventions (a prime consideration
	for alternate name formats is that they can be entered in places that		for alternate name formats is that they can be entered in places that
	normally take DNS context names); this rules out using suffixes that		normally take DNS context names); this rules out using suffixes that
	do not follow the usual letter, digit, and hyphen label convention.		do not follow the usual letter, digit, and hyphen label convention.
	Another proposal was that the ALT TLD instead be a reservation under
	.arpa. This was considered, but rejected for several reasons,
	including:
	1. We wished this to make it clear that this is not in the DNS
	context, and .arpa clearly is.
	2. The use of the string .alt is intended to evoke the alt.*
	hierarchy in Usenet.
	3. We wanted the string to be short and easily used.
	4. A name underneath .arpa would consume at least five additional
	octets of the total 255 octets available in domain names, which
	could put pressure on applications that need long machine-
	generated names.
	5. We are suggesting that the string "ALT" get special treatment in
	resolvers, and shim software. We are concerned that using
	subdomains of an existing TLD (like .arpa) might end up with bad
	implementations misconfiguring / overriding the TLD itself and
	breaking .arpa.
	There is a concern that if there were placed under .arpa,
	inexperienced nameserver operators may inadvertently cover .arpa. A
	more significant concern is that the scope of the issue if the query
	does leak, and the fact that this would then make the root of the
	alternate naming namespace a third level domain, and not a second
	one. A project may be willing to have a name of the form
	example.alt, but example.alt.arpa may be not look as good.
	4. IANA Considerations		4. IANA Considerations
	The IANA is requested to add the ALT string to the "Special-Use		The IANA is requested to add the ALT string to the "Special-Use
	Domain Name" registry ([RFC6761], and reference this document. In		Domain Name" registry ([RFC6761], and reference this document. In
	addition, the "Locally Served DNS Zones" ([RFC6303]) registry should		addition, the "Locally Served DNS Zones" ([RFC6303]) registry should
	be updated to reference this document.		be updated to reference this document.
	4.1. Domain Name Reservation Considerations		4.1. Domain Name Reservation Considerations
	This section is to satisfy the requirement in Section 5 of RFC6761.		This section is to satisfy the requirement in Section 5 of RFC6761.
	skipping to change at page 7, line 49 ¶		skipping to change at page 6, line 27 ¶
	"alt" names in the normal way to any person or entity. These		"alt" names in the normal way to any person or entity. These
	"alt" names are defined by protocol specification to be		"alt" names are defined by protocol specification to be
	nonexistent, and they fall outside the set of names available for		nonexistent, and they fall outside the set of names available for
	allocation by registries/registrars.		allocation by registries/registrars.
	5. Security Considerations		5. Security Considerations
	One of the motivations for the creation of the alt pseudo-TLD is that		One of the motivations for the creation of the alt pseudo-TLD is that
	unmanaged labels in the managed root name space are subject to		unmanaged labels in the managed root name space are subject to
	unexpected takeover if the manager of the root name space decides to		unexpected takeover if the manager of the root name space decides to
	delegate the unmanaged label.		delegate the unmanaged label. Another motivation to to increase use
			privacy for those users who do use alternate name resolution systems,
			by limiting how far these queries leak if used on a system which does
			not implement the alternate resolution system.
	The unmanaged and "registration not required" nature of labels		The unmanaged and "registration not required" nature of labels
	beneath .alt provides the opportunity for an attacker to re-use the		beneath .alt provides the opportunity for an attacker to re-use the
	chosen label and thereby possibly compromise applications dependent		chosen label and thereby possibly compromise applications dependent
	on the special host name.		on the special host name.
	6. Acknowledgements		6. Acknowledgements
	We would also like to thank Joe Abley, Mark Andrews, Marc Blanchet,		We would also like to thank Joe Abley, Mark Andrews, Marc Blanchet,
	John Bond, Stephane Bortzmeyer, David Cake, David Conrad, Patrik		John Bond, Stephane Bortzmeyer, David Cake, David Conrad, Patrik
	Faltstrom, Olafur Gudmundsson, Paul Hoffman, Joel Jaeggli, Ted Lemon,		Faltstrom, Olafur Gudmundsson, Paul Hoffman, Joel Jaeggli, Ted Lemon,
	Edward Lewis, George Michaelson, Ed Pascoe, Arturo Servin, and Paul		Edward Lewis, George Michaelson, Ed Pascoe, Arturo Servin, and Paul
	Vixie for feedback.		Vixie for feedback.
			Christian Grothoff was also very helpful.
	7. Normative References		7. Normative References
	[I-D.ietf-dnsop-dns-terminology]		[I-D.tldr-sutld-ps]
	Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS		Lemon, T., Droms, R., and W. Kumari, "Special-Use Names
	Terminology", draft-ietf-dnsop-dns-terminology-05 (work in		Problem Statement", draft-tldr-sutld-ps-04 (work in
	progress), September 2015.		progress), September 2016.
	[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",		[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
	STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,		STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
	<http://www.rfc-editor.org/info/rfc1034>.		<http://www.rfc-editor.org/info/rfc1034>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/		Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
	RFC2119, March 1997,		RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
	[RFC6303] Andrews, M., "Locally Served DNS Zones", BCP 163, RFC		[RFC6303] Andrews, M., "Locally Served DNS Zones", BCP 163, RFC
	6303, DOI 10.17487/RFC6303, July 2011,		6303, DOI 10.17487/RFC6303, July 2011,
	<http://www.rfc-editor.org/info/rfc6303>.		<http://www.rfc-editor.org/info/rfc6303>.
	[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",		[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
	RFC 6761, DOI 10.17487/RFC6761, February 2013,		RFC 6761, DOI 10.17487/RFC6761, February 2013,
	<http://www.rfc-editor.org/info/rfc6761>.		<http://www.rfc-editor.org/info/rfc6761>.
			[RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
			Terminology", RFC 7719, DOI 10.17487/RFC7719, December
			2015, <http://www.rfc-editor.org/info/rfc7719>.
	Appendix A. Changes / Author Notes.		Appendix A. Changes / Author Notes.
	[RFC Editor: Please remove this section before publication ]		[RFC Editor: Please remove this section before publication ]
			From -05 to -06:
			o Removed a large amount of background - we now have the (adopted)
			tldr document for that.
			o Made it clear that pseudo-TLD is not intended to be pejorative.
			o Tried to make it cleat that this is something people can choose to
			use - or not.
	From -04 to -05:		From -04 to -05:
	o Version bump - we are waiting in the queue for progress on SUN,		o Version bump - we are waiting in the queue for progress on SUN,
	bumping this to keep it alive.		bumping this to keep it alive.
	From -03 to -04:		From -03 to -04:
	o 3 changes - the day, the month and the year (a bump to keep		o 3 changes - the day, the month and the year (a bump to keep
	alive).		alive).
End of changes. 22 change blocks.
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