draft-ietf-dnsop-maintain-ds-00.txt		draft-ietf-dnsop-maintain-ds-01.txt
	dnsop O. Gudmundsson		dnsop O. Gudmundsson
	Internet-Draft CloudFlare		Internet-Draft CloudFlare
	Intended status: Informational P. Wouters		Intended status: Informational P. Wouters
	Expires: June 16, 2016 Red Hat		Expires: September 21, 2016 Red Hat
	December 14, 2015		March 20, 2016
	Managing DS records from parent via CDS/CDNSKEY		Managing DS records from parent via CDS/CDNSKEY
	draft-ietf-dnsop-maintain-ds-00		draft-ietf-dnsop-maintain-ds-01
	Abstract		Abstract
	RFC7344 specifies how DNS trust can be maintained in-band between		RFC7344 specifies how DNS trust can be partially maintained in-band
	parent and child. There are two features missing in that		between parent and child. There are two features missing in that
	specification: initial trust setup and removal of trust anchor. This		specification: initial trust setup and removal of trust anchor. This
	document addresses both these omissions.		document addresses both these omissions.
	Changing a domain's DNSSEC status can be a complicated matter		Changing a domain's DNSSEC status can be a complicated matter
	involving many parties. Some of these parties, such as the DNS		involving multiple unrelated parties. Some of these parties, such as
	operator, might not even be known by all organisations involved. The		the DNS operator, might not even be known by all organizations
	inability to enable or disable DNSSEC via in-band signalling is seen		involved. The inability to disable DNSSEC via in-band signalling is
	as a problem or liability that prevents DNSSEC adoption at large		seen as a problem or liability that prevents some DNSSEC adoption at
	scale. This document adds a method for in-band signalling of DNSSEC		large scale. This document adds a method for in-band signalling of
	status changes.		this DNSSEC status changes.
	Initial trust is considered a much harder problem, this document will		Initial trust is considered a much harder problem, this document will
	seek to clarify and simplify the initial acceptance policy.		seek to clarify and simplify the initial acceptance policy.
	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 June 16, 2016.		This Internet-Draft will expire on September 21, 2016.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 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. Removing DS . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Removing a DS Record . . . . . . . . . . . . . . . . . . 3
	1.2. Introducing DS . . . . . . . . . . . . . . . . . . . . . 3		1.2. Introducing a DS record . . . . . . . . . . . . . . . . . 3
	1.3. Notation . . . . . . . . . . . . . . . . . . . . . . . . 3		1.3. Notation . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
	2. The Three Uses of CDS . . . . . . . . . . . . . . . . . . . . 4		2. The Three Uses of CDS . . . . . . . . . . . . . . . . . . . . 4
	2.1. The meaning of CDS ? . . . . . . . . . . . . . . . . . . 4		2.1. The meaning of the CDS RRset . . . . . . . . . . . . . . 5
	3. Enabling DNSSEC via CDS/CDNSKEY . . . . . . . . . . . . . . . 5		3. Enabling DNSSEC via CDS/CDNSKEY . . . . . . . . . . . . . . . 5
	3.1. Accept policy via authenticated channel . . . . . . . . . 5		3.1. Accept policy via authenticated channel . . . . . . . . . 5
	3.2. Accept with extra checks . . . . . . . . . . . . . . . . 5		3.2. Accept with extra checks . . . . . . . . . . . . . . . . 5
	3.3. Accept after delay . . . . . . . . . . . . . . . . . . . 5		3.3. Accept after delay . . . . . . . . . . . . . . . . . . . 6
	3.4. Accept with challenge . . . . . . . . . . . . . . . . . . 6		3.4. Accept with challenge . . . . . . . . . . . . . . . . . . 6
	4. DNSSEC Delete Algorithm . . . . . . . . . . . . . . . . . . . 6		4. DNSSEC Delete Algorithm . . . . . . . . . . . . . . . . . . . 6
	5. Security considerations . . . . . . . . . . . . . . . . . . . 7		5. Security considerations . . . . . . . . . . . . . . . . . . . 7
	6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 7		6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 7
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
	7.1. Normative References . . . . . . . . . . . . . . . . . . 7		7.1. Normative References . . . . . . . . . . . . . . . . . . 8
	7.2. Informative References . . . . . . . . . . . . . . . . . 8		7.2. Informative References . . . . . . . . . . . . . . . . . 8
	Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 8		Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	CDS/CDNSKEY [RFC7344] records are used to signal changes in trust		CDS/CDNSKEY [RFC7344] records are used to signal changes in trust
	anchors, this is a great way to maintain delegations when the DNS		anchors, this is one method to maintain delegations that can be used
	operator has no other way to inform the parent that changes are		when the DNS operator has no other way to inform the parent that
	needed. RFC7344 contains no "delete" signal for the child to tell		changes are needed. RFC7344 contains no "delete" signal for the
	the parent that it wants to change the DNSSEC security of its domain.		child to tell the parent that it wants to remove the DNSSEC security
			for its domain.
	[RFC7344] punted the Initial Trust establishment question and left it		[RFC7344] did not include a method for the Initial Trust
	to each parent to come up with an acceptance policy.		establishment and left it to each parent to come up with an
			acceptance policy.
	1.1. Removing DS		1.1. Removing a DS Record
	This document introduces the delete option for both CDS and CDNSKEY.		This document introduces the delete option for both CDS and CDNSKEY,
	to allow a child to signal the parent to turn off DNSSEC. When a		allowing a child to signal to the parent to turn off DNSSEC. When a
	domain is moved from one DNS operator to another one, sometimes it is		domain is moved from one DNS operator to another one, sometimes it is
	necessary to turn off DNSSEC to facilitate the change of DNS		necessary to turn off DNSSEC to facilitate the change of DNS
	operator. Common scenarios include:		operator. Common scenarios include:
	1 moving from a DNSSEC operator to a non-DNSSEC capable one or one		1 alternative to doing a proper DNSSEC algorithm rollover due to
	that does not support the same algorithms as the old one.		operational limitations such as software limitations.
	2 moving to one that cannot/does-not-want to do a proper DNSSEC		2 moving from a DNSSEC operator to a non-DNSSEC capable operator.
	rollover.
	3 the domain holder does not want DNSSEC.		3 moving to an operator that cannot/does-not-want to do a proper
			DNSSEC rollover.
	4 when moving between two DNS operators that use disjoint sets of		4 when moving between two DNS operators that use disjoint sets of
	algorithms to sign the zone, thus algorithm roll can not be		algorithms to sign the zone, thus an algorithm rollover can not be
	performed.		performed.
	Whatever the reason, the lack of a "remove my DNSSEC" option is		5 the domain holder no longer wants DNSSEC enabled.
	turning into the latest excuse as why DNSSEC cannot be deployed.
	Turing off DNSSEC reduces the security of the domain and thus should		The lack of a "remove my DNSSEC" option is cited as a reason why some
			operators cannot deploy DNSSEC, as this is seen as an operational
			risk.
			Turning off DNSSEC reduces the security of the domain and thus should
	only be done carefully, and that decision should be fully under the		only be done carefully, and that decision should be fully under the
	child domain's control.		child domain's control.
	1.2. Introducing DS		1.2. Introducing a DS record
	The converse issue is how does a child domain instruct the parent it		The converse issue is how a child domain instructs the parent that it
	wants to have a DS record added. This problem is not as hard as many		wants to have a DS record added. This problem can be solved using a
	have assumed, given a few simplifying assumptions. This document		few simplifying assumptions. This document makes the assumption that
	makes the assumption that there are reasonable policies that can be		there are reasonable policies that can be applied and will allow
	applied and will allow automation of trust introduction.		automation of trust introduction.
	Not being able to enable trust via an easily automated mechanism is		Not being able to enable trust via an easily automated mechanism is
	hindering DNSSEC at scale by anyone that does not have automated		hindering DNSSEC at scale for DNS hosters that do not have automated
	access to its parent's "registry".		access to the "registry" of the child zone's parent.
	1.3. Notation		1.3. Notation
	When this document uses the word CDS it implies that the same applies		When this document uses the word CDS it implies that the same applies
	to CDNSKEY and vice versa, the only difference between the two		to CDNSKEY and vice versa. The only difference between the two
	records is how information is represented.		records is how information is represented.
	When the document uses the word "parent" it implies an entity that is		We use RRR to mean Registry Registrar Registrant in the context of
	authorized to insert into parent zone information about this child		DNS domain markets.
	domain. Which entity this is exactly does not matter. It could be
	the Registrar or Reseller that the child domain was purchased from.
	It could be the Registry that the domain is registered in when
	allowed. It could be some other entity when the RRR framework is not
	used.
	We use RRR to mean Registry Registrar Reseller in the context of DNS		When the document uses the word "parent" it implies an entity that is
	domain markets.		authorized to insert DS records into the parent zone on behalf of the
			child domain. Which entity this exactly is does not matter. It
			could be the Registrar or Reseller that the child domain was
			purchased from. It could be the Registry that the domain is
			registered in when allowed. It could be some other entity when the
			RRR framework is not used.
	1.4. Terminology		1.4. Terminology
	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].
	2. The Three Uses of CDS		2. The Three Uses of CDS
	In general there are three operations that a domain wants to		In general there are three operations that a domain wants to
	influence on its parent:		influence on its parent:
	1 Roll over KSK, this means updating the DS records in the parent to		1 Roll over KSK, this means updating the DS records in the parent to
	reflect the new set of KSK's at the child. This could be an ADD		reflect the new set of KSK's at the child. This could be an ADD
	operation, a Delete operation on one or more records while keeping		operation, a DELETE operation on one or more records while keeping
	at least one DS RR, or a full Replace operation		at least one DS RR, or a full REPLACE operation.
	2 Turn off DNSSEC validation, i.e. delete all the DS records		2 Turn off DNSSEC validation, i.e. delete all the DS records.
	3 Enable DNSSEC validation, i.e. place initial DS RRset in the		3 Enable DNSSEC validation, i.e. place an initial DS RRset in the
	parent.		parent.
	Operation 1 is covered in [RFC7344], operations 2 and 3 are defined		Operation 1 is covered in [RFC7344], operations 2 and 3 are defined
	in this document. In many people's minds, those two later operations		in this document. In many people's minds, those two later operations
	carry more risk than the first one. This document argues that 2 is		carry more risk than the first one. This document argues that 2 is
	identical to 1 and the final one is different (but not that		identical to 1 and the third one is different (but not that
	different).		different).
	2.1. The meaning of CDS ?		2.1. The meaning of the CDS RRset
	The fundamental question is what is the semantic meaning of		The semantic meaning of publishing a CDS RRset is interpreted to
	publishing a CDS RRset in a zone? We offer the following		mean:
	interpretation:
	"Publishing a CDS or CDNSKEY record signifies to the parent that the		"Publishing a CDS or CDNSKEY record signals to the parent that the
	child is ready for the corresponding DS records to be synchronized.		child desires that the corresponding DS records be synchronized.
	Every parent or parental agent should have an acceptance policy of		Every parent or parental agent should have an acceptance policy of
	these records for the three different use cases involved: Initial DS		these records for the three different use cases involved: Initial DS
	publication, Key rollover, and Returning to Insecure."		publication, Key rollover, and Returning to Insecure."
	In short, the CDS RRset is an instruction to the parent to modify DS		In short, the CDS RRset is an instruction to the parent to modify DS
	RRset if the CDS and DS RRsets differ. The acceptance policy for CDS		RRset if the CDS and DS RRsets differ. The acceptance policy for CDS
	in the rollover case is "seeing" according to [RFC7344]. The		in the rollover case is "seeing" according to [RFC7344]. The
	acceptance policy in the Delete case is just seeing a CDS RRset with		acceptance policy in the Delete case is seeing a (validly signed) CDS
	the delete operation specified in this document.		RRset with the delete operation specified in this document.
	3. Enabling DNSSEC via CDS/CDNSKEY		3. Enabling DNSSEC via CDS/CDNSKEY
	There are number of different models for managing initial trust, but		There are number of different models for managing initial trust, but
	in the general case, the child wants to enable global validation for		in the general case, the child wants to enable global validation for
	the future. Thus during the period from the time the child publishes		the future. Thus during the period from the time the child publishes
	the CDS until the corresponding DS is published is the period that		the CDS until the corresponding DS is published at the parent is the
	DNS answers for the child could be forged. The goal is to keep this		period that DNS answers for the child could be forged. The goal is
	period as short as possible.		to keep this period as short as possible.
	One important case is how a 3rd party DNS operator can upload its		One important case is how a third party DNS operator can upload its
	DNSSEC information to the parent, so the parent can publish a DS		DNSSEC information to the parent, so the parent can publish a DS
	record for the child. In this case there is a possibility of setting		record for the child. In this case there is a possibility of setting
	up some kind of authentication mechanism and submission mechanism		up some kind of authentication mechanism and submission mechanism
	that is outside the scope of this document.		that is outside the scope of this document.
	Below are some policies that parents can use. These policies assume		Below are some policies that parents can use. These policies assume
	that the notifications are can be authenticated and/or identified.		that the notifications can be verified or authenticated.
	3.1. Accept policy via authenticated channel		3.1. Accept policy via authenticated channel
	In this case the parent is notified via UI/API that CDS exists, the		In this case the parent is notified via UI/API that a CDS RRset
	parent retrieves the CDS and inserts the DS record as requested, if		exists. The parent retrieves the CDS and inserts the corresponding
	the request comes over an authenticated channel.		DS RRset as requested, provided that the request comes over an
			authenticated channel.
	3.2. Accept with extra checks		3.2. Accept with extra checks
	In this case the parent checks that the source of the notification is		In this case the parent checks that the source of the notification is
	allowed to request the DS insertion. The checks could include		allowed to request the DS insertion. The checks could include
	whether this is a trusted entity, whether the nameservers correspond		whether this is a trusted entity, whether the nameservers correspond
	to the requestor, whether there have been any changes in registration		to the requestor, whether there have been any changes in registration
	in the last few days, etc, or the parent can send a notification		in the last few days, etc. The parent can also send a notification
	requesting an confirmation.		requesting a confirmation.
	The end result is that the CDS is accepted at the end of the checks		The end result is that the CDS RRset is accepted at the end of the
	or when the out-of-band confirmation is received.		checks or when the out-of-band confirmation is received.
	3.3. Accept after delay		3.3. Accept after delay
	In this case, if the parent deems the request valid, it starts		In this case, if the parent deems the request valid, it starts
	monitoring the CDS records at the child nameservers over period of		monitoring the CDS RRset at the child nameservers over period of time
	time to make sure nothing changes. After number of checks,		to make sure nothing changes. After some time or after a number of
	preferably from different vantage points, the parent accepts the CDS		checks, preferably from different vantage points in the network, the
	records as a valid signal to update.		parent accepts the CDS RRset as a valid signal to update its DS RRset
			for this child.
	3.4. Accept with challenge		3.4. Accept with challenge
	In this case the parent instructs the requestor to insert some record		In this case the parent instructs the requestor to insert some record
	into the child domain to prove it has the ability to do so (i.e., it		into the child domain to prove it has the ability to do so (i.e., it
	is the operator of the zone).		is the operator of the zone).
	4. DNSSEC Delete Algorithm		4. DNSSEC Delete Algorithm
	The DNSKEY algorithm registry contains two reserved values: 0 and		The DNSKEY algorithm registry contains two reserved values: 0 and
	255[RFC4034]. The CERT record [RFC4398] defines the value 0 to mean		255[RFC4034]. The CERT record [RFC4398] defines the value 0 to mean
	the algorithm in the CERT record is not defined in DNSSEC.		the algorithm in the CERT record is not defined in DNSSEC.
	[rfc-editor remove before publication] For this reason, using the		[rfc-editor remove before publication] For this reason, using the
	value 0 in CDS/CDNSKEY delete operations is potentially problematic,		value 0 in CDS/CDNSKEY delete operations is potentially problematic,
	but we propose that here anyway as the risk is minimal. The		but we propose it here anyway as the risk is minimal. The
	alternative is to reserve one DNSSEC algorithm number for this		alternative is to reserve a DNSSEC algorithm number for this purpose.
	purpose. [rfc-editor end remove]		[rfc-editor end remove]
	Right now, no DNSSEC validator understands algorithm 0 as a valid		Right now, no DNSSEC validator understands algorithm 0 as a valid
	signature algorithm, thus if the validator sees a DNSKEY or DS record		signature algorithm. If a validator sees a DNSKEY or DS record with
	with this value, it will treat it as unknown. Accordingly, the zone		this algorithm value, it MUST treat it as unknown. Accordingly, the
	is treated as unsigned unless there are other algorithms present.		zone is treated as unsigned unless there are other algorithms
			present.
	In the context of CDS and CDNSKEY records, DNSSEC algorithm 0 is		In the context of CDS and CDNSKEY records, DNSSEC algorithm 0 is
	defined and means the entire DS set MUST be removed. The contents of		defined to mean that the entire DS RRset MUST be removed. The
	the records MUST contain only the fixed fields as show below.		contents of the CDS or CDNSKEY RRset MUST contain one RR and only
			contain the fixed fields as shown below.
	1 CDS 0 0 0		1 CDS 0 0 0
	2 CDNSKEY 0 3 0		2 CDNSKEY 0 3 0
			The keying material payload is represented by a single 0. This
	There is no keying material payload in the records, just the command		record is signed in the same way as regular CDS/CDNSKEY RRsets are
	to delete all DS records. This record is signed in the same way as		signed.
	CDS/CDNSKEY is signed.
	Strictly speaking the CDS record could be "CDS X 0 X" as only the		Strictly speaking the CDS record could be "CDS X 0 X" as only the
	DNSKEY algorithm is what signals the delete operation, but for		DNSKEY algorithm is what signals the DELETE operation, but for
	clarity the "0 0 0" notation is mandated, this is not a definition of		clarity the "0 0 0" notation is mandated - this is not a definition
	DS Digest algorithm 0. Same argument applies to "CDNSKEY 0 3 0".		of DS Digest algorithm 0. The same argument applies to "CDNSKEY 0 3
			0", the value 3 in second field is mandated by RFC4034 section 2.1.2.
	Once the parent has verified the CDS/CDNSKEY record and it has passed		Once the parent has verified the CDS/CDNSKEY RRset and it has passed
	other acceptance tests, the DS record MUST be removed. At this point		other acceptance tests, the parent MUST remove the DS RRset. After
	the child can start the process of turning DNSSEC off.		waiting a sufficient amount of time - depending the the parental
			TTL's - the child can start the process of turning off DNSSEC.
	5. Security considerations		5. Security considerations
	This document is about avoiding validation failures when a domain		This document's main goal is to avoid validation failures when a
	moves from one DNS operator to another one. Turing off DNSSEC		domain moves from one DNS operator to another. Turning off DNSSEC
	reduces the security of the domain and thus should only be done as a		reduces the security of the domain and thus should only be done as a
	last resort.		last resort.
	In most cases it is preferable that operators collaborate on the		In most cases it is preferable that operators collaborate on the
	rollover by doing a KSK+ZSK rollover as part of the handoff, but that		rollover by doing a KSK+ZSK rollover as part of the hand-off, but
	is not always possible. This document addresses the case where		that is not always possible. This document addresses the case where
	unsigned state is needed.		unsigned state is needed to complete a rollover.
	Users SHOULD keep in mind that re-establishing trust in delegation		Users SHOULD keep in mind that re-establishing trust in delegation
	can be hard and take a long time thus before going to unsigned all		can be hard and takes a long time. Before deciding to complete the
	options SHOULD be considered.		rollover via an unsigned state, all options SHOULD be considered.
	A parent should ensure that when it is allowing a child to become		A parent SHOULD ensure that when it is allowing a child to become
	securely delegated, that it has a reasonable assurance that the CDS/		securely delegated, that it has a reasonable assurance that the CDS/
	CDNSKEY that is used to bootstrap the security on is visible from a		CDNSKEY RRset that is used to bootstrap the security is visible from
	geographically and network topology diverse view. It should also		a geographically and network topology diverse view. It SHOULD also
	ensure the the zone would validate if the parent published the DS		ensure the the zone validates correctly if the parent publishes the
	record. A parent zone might also consider sending an email to its		DS record. A parent zone might also consider sending an email to its
	contact addresses to give the child a warning that security will be		contact addresses to give the child zone a warning that security will
	enabled after a certain about of wait time - thus allowing a child		be enabled after a certain about of wait time - thus allowing a child
	administrator to cancel the request.		administrator to cancel the request.
	This document does not introduce any new problems, but like Negative
	Trust Anchor[RFC7646], it addresses operational reality.
	6. IANA considerations		6. IANA considerations
	This document updates the following IANA registries: "DNS Security		This document updates the following IANA registries: "DNS Security
	Algorithm Numbers"		Algorithm Numbers"
	Algorithm 0 adds a reference to this document.		Algorithm 0 adds a reference to this document.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	skipping to change at page 8, line 21 ¶		skipping to change at page 8, line 30 ¶
	[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>.
	[RFC4398] Josefsson, S., "Storing Certificates in the Domain Name		[RFC4398] Josefsson, S., "Storing Certificates in the Domain Name
	System (DNS)", RFC 4398, DOI 10.17487/RFC4398, March 2006,		System (DNS)", RFC 4398, DOI 10.17487/RFC4398, March 2006,
	<http://www.rfc-editor.org/info/rfc4398>.		<http://www.rfc-editor.org/info/rfc4398>.
	[RFC7646] Ebersman, P., Kumari, W., Griffiths, C., Livingood, J.,
	and R. Weber, "Definition and Use of DNSSEC Negative Trust
	Anchors", RFC 7646, DOI 10.17487/RFC7646, September 2015,
	<http://www.rfc-editor.org/info/rfc7646>.
	Appendix A. Acknowledgements		Appendix A. Acknowledgements
	This document is generated using the mmark tool that Miek Gieben has		This document is generated using the mmark tool that Miek Gieben has
	developed.		developed.
	Authors' Addresses		Authors' Addresses
	Olafur Gudmundsson		Olafur Gudmundsson
	CloudFlare		CloudFlare
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