draft-ietf-dnsop-child-syncronization-02.txt		draft-ietf-dnsop-child-syncronization-03.txt
	DNSOP W. Hardaker		DNSOP W. Hardaker
	Internet-Draft Parsons, Inc.		Internet-Draft Parsons, Inc.
	Intended status: Standards Track July 3, 2014		Intended status: Standards Track September 3, 2014
	Expires: January 4, 2015		Expires: March 7, 2015
	Child To Parent Synchronization in DNS		Child To Parent Synchronization in DNS
	draft-ietf-dnsop-child-syncronization-02		draft-ietf-dnsop-child-syncronization-03
	Abstract		Abstract
	This document specifies how a child zone in the DNS can publish a		This document specifies how a child zone in the DNS can publish a
	record to indicate to a parental agent that it may copy and process		record to indicate to a parental agent that the parental agent may
	certain records from the child zone. The existence of and value		copy and process certain records from the child zone. The existence
	change of the record may be monitored by a parental agent and acted		of the record and any change in its value can be monitored by a
	on as appropriate.		parental agent and acted on depending on local 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 January 4, 2015.		This Internet-Draft will expire on March 7, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 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
	skipping to change at page 3, line 9		skipping to change at page 3, line 9
	7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12		7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12		8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	8.1. Normative References . . . . . . . . . . . . . . . . . . . 12		8.1. Normative References . . . . . . . . . . . . . . . . . . . 12
	8.2. Informative References . . . . . . . . . . . . . . . . . . 13		8.2. Informative References . . . . . . . . . . . . . . . . . . 13
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13
	1. Introduction		1. Introduction
	This document specifies how a child zone in the DNS ([RFC1034],		This document specifies how a child zone in the DNS ([RFC1034],
	[RFC1035]) can publish a record to indicate to a parental agent that		[RFC1035]) can publish a record to indicate to a parental agent that
	it may copy and process certain records from the child zone. The		can copy and process certain records from the child zone. The
	existence of and value change of the record may be monitored by a		existence of the record and any change in its value can be monitored
	parental agent and acted on as appropriate.		by a parental agent and acted on depending on local policy.
	Currently today, some resource records (RRs) in a parent zone are		Currently today, some resource records (RRs) in a parent zone are
	typically expected to be in-sync with the source data in the child's		typically expected to be in sync with the source data in the child's
	zone. The most common records that should match are the nameserver		zone. The most common records that should match are the nameserver
	(NS) records and any necessary associated address records (A and		(NS) records and any necessary associated address records (A and
	AAAA), also known as "glue records". These records are referred to		AAAA), also known as "glue records". These records are referred to
	as "delegation records".		as "delegation records".
	It has been traditionally challenging for child DNS operators to		It has been challenging for operators of child DNS zones to update
	update their delegation records within the parent's set in a timely		their delegation records within the parent's set in a timely fashion.
	fashion. This difficulty is frequently from simple operator laziness		These difficulties may stem from operator laziness, as well as from
	or because of the complexities of maintaining a large number of DNS		the complexities of maintaining a large number of DNS zones. Having
	zones. Having an automated mechanism for signaling updates will		an automated mechanism for signaling updates will greatly ease the
	greatly ease the child zone operator's maintenance burden and improve		child zone operator's maintenance burden and improve the robustness
	the robustness of the DNS as a whole.		of the DNS as a whole.
	This draft introduces a new Resource Record Type (RRType) named		This draft introduces a new Resource Record Type (RRType) named
	"CSYNC" that indicates which delegation records published by a child		"CSYNC" that indicates which delegation records published by a child
	DNS operator should be processed by a parental agent and used to		DNS operator should be processed by a parental agent and used to
	update the parent zone's DNS data.		update the parent zone's DNS data.
	This specification was not designed to synchronize DNSSEC security		This specification was not designed to synchronize DNSSEC security
	records, such as DS RRsets. For a solution to this problem, see the		records, such as DS RRsets. For a solution to this problem, see the
	complimentary solution		complementary solution
	[I-D.ietf-dnsop-delegation-trust-maintainance], which is designed to		[I-D.ietf-dnsop-delegation-trust-maintainance], which is designed to
	maintain security delegation information. In addition, this		maintain security delegation information. In addition, this
	specification does not address how to perform bootstrapping		specification does not address how to perform bootstrapping
	operations, including to get the required initial DNSSEC-secured		operations, including to get the required initial DNSSEC-secured
	operating environment in place.		operating environment in place.
	1.1. Terminology Used in This Document		1.1. Terminology Used in This Document
	The terminology used in this document is defined in this section.		The terminology used in this document is defined in this section.
	skipping to change at page 4, line 28		skipping to change at page 4, line 28
	The CSYNC RRType contains, in its RDATA component, these parts: an		The CSYNC RRType contains, in its RDATA component, these parts: an
	SOA serial number, a set of flags and a simple bit-list indicating		SOA serial number, a set of flags and a simple bit-list indicating
	the DNS RRTypes in the child that should be processed by the parental		the DNS RRTypes in the child that should be processed by the parental
	agent in order to modify the DNS delegation records within the		agent in order to modify the DNS delegation records within the
	parent's zone for the child DNS operator. Child DNS operators		parent's zone for the child DNS operator. Child DNS operators
	wanting a parental agent to perform the synchronization steps		wanting a parental agent to perform the synchronization steps
	outlined in this document MUST publish a CSYNC record at the apex of		outlined in this document MUST publish a CSYNC record at the apex of
	the child zone. Parental agent implementations MAY choose to query		the child zone. Parental agent implementations MAY choose to query
	child zones for this record and process DNS record data as indicated		child zones for this record and process DNS record data as indicated
	by the Type Bit Map field in the RDATA of the CSYNC record. How the		by the Type Bit Map field in the RDATA of the CSYNC record. How the
	data is processed is described in Section Section 3.		data is processed is described in Section 3.
	Parental agents MUST process the entire set of child data indicated		Parental agents MUST process the entire set of child data indicated
	by the Type Bit Map field (i.e., all record types indicated along		by the Type Bit Map field (i.e., all record types indicated along
	with all of the necessary records to support processing of that type)		with all of the necessary records to support processing of that type)
	or else parental agents MUST NOT make any changes to parental records		or else parental agents MUST NOT make any changes to parental records
	at all. Errors due to unsupported Type Bit Map bits, or otherwise		at all. Errors due to unsupported Type Bit Map bits, or otherwise
	nonpunishable data, SHALL result in no change to the parent zone's		nonpunishable data, SHALL result in no change to the parent zone's
	delegation information for the Child. Parental agents MUST ignore a		delegation information for the Child. Parental agents MUST ignore a
	Child's CSYNC RDATA set if multiple CSYNC resource records are found;		Child's CSYNC RDATA set if multiple CSYNC resource records are found;
	only a single CSYNC record should ever be present.		only a single CSYNC record should ever be present.
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	flag that is unknown to or unsupported by the parental agent.		flag that is unknown to or unsupported by the parental agent.
	2.1.1.2.1. The Type Bit Map Field		2.1.1.2.1. The Type Bit Map Field
	The Type Bit Map field indicates the record types to be processed by		The Type Bit Map field indicates the record types to be processed by
	the parental agent, according to the procedures in Section Section 3.		the parental agent, according to the procedures in Section Section 3.
	The Type Bit Map field is encoded in the same way as the Type Bit		The Type Bit Map field is encoded in the same way as the Type Bit
	Maps field of the NSEC record, described in [RFC4034], Section 4.1.2.		Maps field of the NSEC record, described in [RFC4034], Section 4.1.2.
	If a bit has been set that a parental agent implementation does not		If a bit has been set that a parental agent implementation does not
	understand, the parental agent MUST NOT act upon the record.		understand, the parental agent MUST NOT act upon the record.
	Specifically: a parental agent must not copy data blindly; An IETF		Specifically: a parental agent must not copy data blindly and must
	proposed (or higher) standard specification must exist that defines		understand the semantics associated with an bit in the Type Bit Map
	how the data should be processed for a given bit.		field that has been set to 1.
	2.1.2. The CSYNC Presentation Format		2.1.2. The CSYNC Presentation Format
	The CSYNC presentation format is as follows:		The CSYNC presentation format is as follows:
	The SOA Serial field is represented as an integer.		The SOA Serial field is represented as an integer.
	The Flags field is represented as an integer.		The Flags field is represented as an integer.
	The Type Bit Map field is represented as a sequence of RR type		The Type Bit Map field is represented as a sequence of RR type
	skipping to change at page 7, line 21		skipping to change at page 7, line 21
	proven by NSEC or NSEC3 is to be considered successful).		proven by NSEC or NSEC3 is to be considered successful).
	Parental agents MAY:		Parental agents MAY:
	Process the CSYNC record immediately if the "immediate" flag is		Process the CSYNC record immediately if the "immediate" flag is
	set. If the "immediate" flag is not set, the parental agent MUST		set. If the "immediate" flag is not set, the parental agent MUST
	NOT act until the zone administrator approves the operation		NOT act until the zone administrator approves the operation
	through an out-of-band mechanism (such as through pushing a button		through an out-of-band mechanism (such as through pushing a button
	via a web interface).		via a web interface).
	Require that the child zone administrator approve the operation		Choose not to process the CSYNC record immediately, even if the
	through an out-of-band mechanism (such as through pushing a button		"immediate" flag is set. That is, a parental agent might require
	via a web interface). I.e., a parental agent MAY choose not to		the child zone administrator approve the operation through an out-
	support the "immediate" flag.		of-band mechanism (such as through pushing a button via a web
			interface).
	Note: how the approval is done out-of-band is outside the scope of		Note: how the approval is done out-of-band is outside the scope of
	this document and is implementation-specific to parental agents.		this document and is implementation-specific to parental agents.
	3.1. Processing Procedure		3.1. Processing Procedure
	The following shows a sequence of steps that SHOULD be used when		The following shows a sequence of steps that SHOULD be used when
	collecting and processing CSYNC records from a child zone. Because		collecting and processing CSYNC records from a child zone. Because
	DNS queries are not allowed to contain more than one "question" at a		DNS queries are not allowed to contain more than one "question" at a
	time, a sequence of requests is needed. When processing a CSYNC		time, a sequence of requests is needed. When processing a CSYNC
	skipping to change at page 7, line 50		skipping to change at page 7, line 51
	1. Query for the child zone's SOA record		1. Query for the child zone's SOA record
	2. Query for the child zone's CSYNC record		2. Query for the child zone's CSYNC record
	3. Query for the child zone's data records, as required by the CSYNC		3. Query for the child zone's data records, as required by the CSYNC
	record's Type Bit Map field		record's Type Bit Map field
	4. Query for the child zone's SOA record again		4. Query for the child zone's SOA record again
	If the SOA records from the first and last steps have different		If the SOA records from the first and last steps have different
	serial numbers, then the CSYNC record obtained in the second set MUST		serial numbers (for example, because the zone was edited and
	NOT be processed. The operation MAY be restarted or retried in the		republished during the interval between steps 1 and 4), then the
	future.		CSYNC record obtained in the second set MUST NOT be processed. The
			operation MAY be restarted or retried in the future.
	If the SOA serial numbers are equal but less than the CSYNC record's		If the SOA serial numbers are equal but less than the CSYNC record's
	SOA Serial Field [RFC1982], the record MUST NOT be processed. If		SOA Serial Field [RFC1982], the record MUST NOT be processed. If
	state is being kept by the parental agent and the SOA serial number		state is being kept by the parental agent and the SOA serial number
	is less than the last time a CSYNC record was processed, this CSYNC		is less than the last time a CSYNC record was processed, this CSYNC
	record SHOULD NOT be processed. Similarly, if state is being kept by		record SHOULD NOT be processed. Similarly, if state is being kept by
	the parental agent and the SOA Serial Field of the CSYNC record is		the parental agent and the SOA Serial Field of the CSYNC record is
	less than the SOA Serial Field of the CSYNC record from last time,		less than the SOA Serial Field of the CSYNC record from last time,
	then this CSYNC record SHOULD NOT be processed.		then this CSYNC record SHOULD NOT be processed.
	skipping to change at page 8, line 47		skipping to change at page 8, line 49
	zone. Similarly, if NS records in the parent's delegation records		zone. Similarly, if NS records in the parent's delegation records
	for the child contain records that have been removed in the child's		for the child contain records that have been removed in the child's
	NS set, then they should be removed in the parent's set as well.		NS set, then they should be removed in the parent's set as well.
	Parental agents MAY refuse to perform NS updates if the replacement		Parental agents MAY refuse to perform NS updates if the replacement
	records fail to meet NS record policies required by the parent zone		records fail to meet NS record policies required by the parent zone
	(e.g. "every child zone must have at least 2 NS records").		(e.g. "every child zone must have at least 2 NS records").
	3.2.2. The A and AAAA types		3.2.2. The A and AAAA types
	The A and AAAA type flags indicates that the A and AAAA,		The A and AAAA type flags indicates that the A and AAAA address glue
	respectively, address glue records for in-bailiwick NS records within		records for in-bailiwick NS records within the child zone should be
	the child zone should be copied into the parent's delegation		copied into the parent's delegation information.
	information.
	Queries should be sent by the parental agent to determine the A and		Queries should be sent by the parental agent to determine the A and
	AAAA record addresses for each NS record within a NS set for the		AAAA record addresses for each NS record within a NS set for the
	child that are in-bailiwick.		child that are in-bailiwick.
	Note: only the matching types should be queried. E.g., if the AAAA		Note: only the matching types should be queried. E.g., if the AAAA
	bit has not been set, then the AAAA records (if any) in the parent's		bit has not been set, then the AAAA records (if any) in the parent's
	delegation should remain as is. If a given address type is set and		delegation should remain as is. If a given address type is set and
	the child's zone contains no data for that type (as proven by		the child's zone contains no data for that type (as proven by
	appropriate NSEC or NSEC3 records), then the result in the parent's		appropriate NSEC or NSEC3 records), then the result in the parent's
	skipping to change at page 9, line 34		skipping to change at page 9, line 36
	4. Operational Considerations		4. Operational Considerations
	There are a number of important operational aspects to consider when		There are a number of important operational aspects to consider when
	deploying a CSYNC RRType.		deploying a CSYNC RRType.
	4.1. Error Reporting		4.1. Error Reporting
	There is no inline mechanism for a parental agent to report errors to		There is no inline mechanism for a parental agent to report errors to
	operators of child zones. Thus, the only error reporting mechanisms		operators of child zones. Thus, the only error reporting mechanisms
	must be out of band, such as through a web console or over email.		must be out of band, such as through a web console or over email.
	Child operators utilizing the "immediate" flag that fail to see an		Parental agents SHOULD, at a minimum, at least log errors encountered
	update within the parental agent's specified operational window		when processing CSYNC records. Child operators utilizing the
	should access the parental agent's error logging interface to		"immediate" flag that fail to see an update within the parental
	determine why an update failed to be processed.		agent's specified operational window should access the parental
			agent's error logging interface to determine why an update failed to
			be processed.
	4.2. Child Nameserver Selection		4.2. Child Nameserver Selection
	Parental agents will need to poll child nameservers in search of		Parental agents will need to poll child nameservers in search of
	CSYNC records and related data records.		CSYNC records and related data records.
	Parental agents MAY perform best-possible verification by querying		Parental agents MAY perform best-possible verification by querying
	all NS records for available data to determine which has the most		all NS records for available data to determine which has the most
	recent SOA and CSYNC version (in an ideal world, they would all be		recent SOA and CSYNC version (in an ideal world, they would all be
	equal, but this is not possible in practice due to synchronization		equal, but this is not possible in practice due to synchronization
	delays and transfer failures).		delays and transfer failures).
	Parental agents MAY offer a configuration interface to allow child		Parental agents MAY offer a configuration interface to allow child
	operators to specify which nameserver should be considered the master		operators to specify which nameserver should be considered the master
	to send data queries too. This master MAY be a different nameserver		to send data queries too. Note that this master could be a different
	than the publically listed nameservers in the NS set (i.e., it may be		nameserver than the publically listed nameservers in the NS set
	a "hidden master").		(i.e., it may be a "hidden master").
	Parental agents MAY offer a programmatic interface to let children		Parental agents with a large number of clients may choose to offer a
	indicate that new CSYNC records and data are available for polling.		programmatic interface to let their children indicate that new CSYNC
			records and data are available for polling rather than polling every
			child on a frequent basis.
	4.3. Out-of-balliwick NS Records		4.3. Out-of-balliwick NS Records
	When a zone contains NS records where the domain-name pointed at does		When a zone contains NS records where the domain-name pointed at does
	not fall within the zone itself, there is no way for the parent to		not fall within the zone itself, there is no way for the parent to
	safely update the associated glue records. Thus, the child DNS		safely update the associated glue records. Thus, the child DNS
	operator MAY indicate that the NS records should be synchronized, and		operator MAY indicate that the NS records should be synchronized, and
	may set any glue record flags (A, AAAA) as well, but the parent will		MAY set any glue record flags (A, AAAA) as well, but the parent will
	only update those glue records which are below the child's delegation		only update those glue records which are below the child's delegation
	point.		point.
	Children deploying NS records pointing to domain-names within their		Children deploying NS records pointing to domain-names within their
	own children (the "grandchildren") SHOULD ensure the grandchildren's		own children (the "grandchildren") SHOULD ensure the grandchildren's
	associated glue records are properly set before publishing the CSYNC		associated glue records are properly set before publishing the CSYNC
	record. I.e., it is imperative that proper communication and		record. I.e., it is imperative that proper communication and
	synchronization exist between the child and the grandchild.		synchronization exist between the child and the grandchild.
	4.4. Documented Parental Agent Type Support		4.4. Documented Parental Agent Type Support
	skipping to change at page 11, line 29		skipping to change at page 11, line 34
	designed to synchronize DNSSEC security records, such as DS pointers.		designed to synchronize DNSSEC security records, such as DS pointers.
	For such a solution, please see the complimentary solution		For such a solution, please see the complimentary solution
	[I-D.ietf-dnsop-delegation-trust-maintainance] for maintaining		[I-D.ietf-dnsop-delegation-trust-maintainance] for maintaining
	security delegation information.		security delegation information.
	6. IANA Considerations		6. IANA Considerations
	This document defines a new DNS Resource Record Type, named "CSYNC".		This document defines a new DNS Resource Record Type, named "CSYNC".
	The IANA is requested to assign a code point from the "Resource		The IANA is requested to assign a code point from the "Resource
	Record (RR) TYPEs" sub-registry of the "Domain Name System (DNS)		Record (RR) TYPEs" sub-registry of the "Domain Name System (DNS)
	Parameters" registry		Parameters" registry (http://www.iana.org/assignments/dns-parameters)
	(http://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml)
	for this record.		for this record.
	TYPE Value Meaning Reference		TYPE Value Meaning Reference
	----- ------ -------------------------- -----------		----- ------ -------------------------- -----------
	CSYNC TBA Child To Parent Synchronization [This document]		CSYNC TBD Child To Parent Synchronization [This document]
	[ To be removed prior to publication: The CDS (59), CDNSKEY (60) and
	the CSYNC records are all conceptually similar - if the code-point 61
	happens to still be Unassigned when the IANA processes this, it would
	be nice if that could be used for this.]
	The IANA is also requested to create and maintain a sub-registry (the		The IANA is also requested to create and maintain a sub-registry (the
	"Child Synchronization (CSYNC) Flags" registry) of the "Domain Name		"Child Synchronization (CSYNC) Flags" registry) of the "Domain Name
	System (DNS) Parameters" registry. The initial values for this		System (DNS) Parameters" registry. The initial values for this
	registry are below. Assignment of new flag values are subject to		registry are below. Assignment of new flag values are subject to
	"RFC Required" specifications [RFC5226].		"RFC Required" specifications [RFC5226].
	This registry will hold a set of single-bit "Flags" for use in the		This registry will hold a set of single-bit "Flags" for use in the
	CSYNC record within the 16 bit Flags field. Thus, a maximum of 16		CSYNC record within the 16 bit Flags field. Thus, a maximum of 16
	flags may be defined.		flags may be defined.
	The initial assignments in this registry are:		The initial assignments in this registry are:
	Bit Flag Description Reference		Bit Flag Description Reference
	---- ------ ------------- -----------		---- ------ ------------- -----------
	Bit 0 immediate Immediately process this [This document,		Bit 0 immediate Immediately process this [This document,
	CSYNC record. Section 3]		CSYNC record. Section 3]
	Bit 1 soaminimum Require a SOA serial [This document,		Bit 1 soaminimum Require a SOA serial [This document,
	number greater than the Section 2.1.1.1]		number greater than the Section 2.1.1.1]
	one specified.		one specified.
			For new assignments to be made to this registry, a new RFC must be
			published via a Standards Action.
	7. Acknowledgments		7. Acknowledgments
	A thank you goes out to Warren Kumari and Olafur Gu[eth]mundsson,		A thank you goes out to Warren Kumari and Olafur Gu[eth]mundsson,
	who's work on the CDS record type helped inspire the work in this		who's work on the CDS record type helped inspire the work in this
	document, as well as the definition for the "parental agent"		document, as well as the definition for the "parental agent"
	definition and significant contributions to the text. A thank you		definition and significant contributions to the text. A thank you
	also goes out to Ed Lewis, who the author held many conversations		also goes out to Ed Lewis, with whom the author held many
	with about the issues surrounding parent/child relationships and		conversations with about the issues surrounding parent/child
	synchronization. Much of the work in this document is derived from		relationships and synchronization. Much of the work in this document
	the careful existing analysis of these three esteemed colleagues.		is derived from the careful existing analysis of these three esteemed
	Thank you to the following people who have contributed text to the		colleagues. Thank you to the following people who have contributed
	document: Matthijs Mekking and Petr Spacek.		text to the document: Matthijs Mekking and Petr Spacek.
	A special thanks goes to Roy Arends, for taking the "bite out of that		A special thanks goes to Roy Arends, for taking the "bite out of that
	hamburger" challenge while discussing this document.		hamburger" challenge while discussing this document.
	8. References		8. References
	8.1. Normative References		8.1. Normative References
	[RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,		[RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
	August 1996.		August 1996.
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