draft-ietf-dnsop-delegation-trust-maintainance-14.txt   rfc7344.txt 
dnsop W. Kumari Internet Engineering Task Force (IETF) W. Kumari
Internet-Draft Google Request for Comments: 7344 Google
Intended status: Informational O. Gudmundsson Category: Informational O. Gudmundsson
Expires: December 12, 2014 Shinkuro Inc. ISSN: 2070-1721 OGUD Consulting
G. Barwood G. Barwood
September 2014
June 10, 2014
Automating DNSSEC Delegation Trust Maintenance Automating DNSSEC Delegation Trust Maintenance
draft-ietf-dnsop-delegation-trust-maintainance-14
Abstract Abstract
This document describes a method to allow DNS operators to more This document describes a method to allow DNS Operators to more
easily update DNSSEC Key Signing Keys using the DNS as communication easily update DNSSEC Key Signing Keys using the DNS as a
channel. The technique described is aimed at delegations in which it communication channel. The technique described is aimed at
is currently hard to move information from the child to parent. delegations in which it is currently hard to move information from
the Child to Parent.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
This Internet-Draft will expire on December 12, 2014. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7344.
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.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Requirements Notation . . . . . . . . . . . . . . . . . . 4 1.2. Requirements Notation . . . . . . . . . . . . . . . . . . 4
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. DNS Delegations . . . . . . . . . . . . . . . . . . . . . 4 2.1. DNS Delegations . . . . . . . . . . . . . . . . . . . . . 5
2.2. Relationship Between Parent and Child DNS Operator . . . 5 2.2. Relationship between Parent and Child DNS Operators . . . 5
2.2.1. Solution Space . . . . . . . . . . . . . . . . . . . 6 2.2.1. Solution Space . . . . . . . . . . . . . . . . . . . 6
2.2.2. DNSSEC key change process . . . . . . . . . . . . . . 6 2.2.2. DNSSEC Key Change Process . . . . . . . . . . . . . . 7
3. CDS / CDNSKEY (Child DS / Child DNSKEY) Record Definitions . 7 3. CDS (Child DS) and CDNSKEY (Child DNSKEY) Record Definitions 7
3.1. CDS Resource Record Format . . . . . . . . . . . . . . . 8 3.1. CDS Resource Record Format . . . . . . . . . . . . . . . 8
3.2. CDNSKEY Resource Record Format . . . . . . . . . . . . . 8 3.2. CDNSKEY Resource Record Format . . . . . . . . . . . . . 8
4. Automating DS Maintenance With CDS / CDNSKEY records . . . . 8 4. Automating DS Maintenance with CDS/CDNSKEY Records . . . . . 8
4.1. CDS / CDNSKEY Processing Rules . . . . . . . . . . . . . 8 4.1. CDS and CDNSKEY Processing Rules . . . . . . . . . . . . 9
5. CDS / CDNSKEY Publication . . . . . . . . . . . . . . . . . . 9 5. CDS/CDNSKEY Publication . . . . . . . . . . . . . . . . . . . 9
6. Parent Side CDS / CDNSKEY Consumption . . . . . . . . . . . . 9 6. Parent-Side CDS/CDNSKEY Consumption . . . . . . . . . . . . . 9
6.1. Detecting a Changed CDS / CDNSKEY . . . . . . . . . . . . 9 6.1. Detecting a Changed CDS/CDNSKEY . . . . . . . . . . . . . 10
6.1.1. CDS / CDNSKEY Polling . . . . . . . . . . . . . . . . 10 6.1.1. CDS/CDNSKEY Polling . . . . . . . . . . . . . . . . . 10
6.1.2. Polling Triggers . . . . . . . . . . . . . . . . . . 10 6.1.2. Polling Triggers . . . . . . . . . . . . . . . . . . 11
6.2. Using the New CDS / CDNSKEY Records . . . . . . . . . . . 11 6.2. Using the New CDS/CDNSKEY Records . . . . . . . . . . . . 11
6.2.1. Parent Calculates DS . . . . . . . . . . . . . . . . 11 6.2.1. Parent Calculates DS . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12
9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
11.1. Normative References . . . . . . . . . . . . . . . . . . 14 11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 15 11.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. RRR background . . . . . . . . . . . . . . . . . . . 15 Appendix A. RRR Background . . . . . . . . . . . . . . . . . . . 17
Appendix B. CDS key rollover example . . . . . . . . . . . . . . 16 Appendix B. CDS Key Rollover Example . . . . . . . . . . . . . . 17
Appendix C. Changes / Author Notes. . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
The first time a DNS operator signs a zone, they need to communicate The first time a DNS Operator signs a zone, they need to communicate
the keying material to their parent through some out-of-band method the keying material to their Parent through some out-of-band method
to complete the chain of trust. Depending on the desires of the to complete the chain of trust. Depending on the desires of the
parent, the child might send their DNSKEY record, a DS record, or Parent, the Child might send their DNSKEY record, a DS record, or
both. both.
Each time the child changes the key that is represented in the Each time the Child changes the key that is represented in the
parent, the updated and / or deleted key information has to be Parent, the updated and/or deleted key information has to be
communicated to the parent and published in the parent's zone. How communicated to the Parent and published in the Parent's zone. How
this information is sent to the parent depends on the relationship this information is sent to the Parent depends on the relationship
the child has with the parent. In many cases this is a manual the Child has with the Parent. In many cases this is a manual
process, and not an easy one. For each key change, there may be up process -- and not an easy one. For each key change, there may be up
to two interactions with the parent. Any manual process is to two interactions with the Parent. Any manual process is
susceptible to mistakes and / or errors. In addition, due to the susceptible to mistakes and/or errors. In addition, due to the
annoyance factor of the process, operators may avoid changing keys or annoyance factor of the process, Operators may avoid changing keys or
skip needed steps to publish the new DS at the parent. skip needed steps to publish the new DS at the Parent.
DNSSEC provides data integrity to information published in DNS; thus DNSSEC provides data integrity to information published in DNS; thus,
DNS publication can be used to automate maintenance of delegation DNS publication can be used to automate maintenance of delegation
information. This document describes a method to automate information. This document describes a method to automate
publication of subsequent DS records, after the initial one has been publication of subsequent DS records after the initial one has been
published. published.
Readers are expected to be familiar with DNSSEC, including [RFC4033], Readers are expected to be familiar with DNSSEC, including [RFC4033],
[RFC4034], [RFC4035], [RFC5011] and [RFC6781]. [RFC4034], [RFC4035], [RFC5011], and [RFC6781].
This document outlines a technique in which the parent periodically This document outlines a technique in which the Parent periodically
(or upon request) polls its signed children and automatically (or upon request) polls its signed Children and automatically
publishes new DS records. To a large extent, the procedures this publishes new DS records. To a large extent, the procedures this
document follows are as described in [RFC6781] section 4.1.2. document follows are as described in [RFC6781], Section 4.1.2.
This technique is designed to be friendly both to fully automated This technique is designed to be friendly both to fully automated
tools and humans. Fully automated tools can perform all the actions tools and humans. Fully automated tools can perform all the actions
needed without human intervention, and thus can monitor when it is needed without human intervention and thus can monitor when it is
safe to move to the next step. safe to move to the next step.
The solution described in this document only allows transferring The solution described in this document only allows transferring
information about DNSSEC keys (DS and DNSKEY) from the child to the information about DNSSEC keys (DS and DNSKEY) from the Child to the
parental agent. It lists exactly what the parent should publish, and Parental Agent. It lists exactly what the Parent should publish and
allows for publication of stand-by keys. A different protocol, allows for publication of standby keys. A different protocol,
[I-D.csync], can be used to maintain other important delegation [CPSYNC-DNS], can be used to maintain other important delegation
information, such as NS and glue. These two protocols have been kept information, such as NS and glue records. These two protocols have
as separate solutions because the problems are fundamentally been kept as separate solutions because the problems are
different, and a combined solution is overly complex. fundamentally different and a combined solution is overly complex.
This document describes a method for automating maintenance of the This document describes a method for automating maintenance of the
delegation trust information, and proposes a polled / periodic delegation trust information and proposes a polled/periodic trigger
trigger for simplicity. Some users may prefer a different trigger, for simplicity. Some users may prefer a different trigger, for
for example a button on a webpage, a REST interface or a DNS NOTIFY. example, a button on a web page, a REST interface, or a DNS NOTIFY.
These alternate / additional triggers are not discussed in this These alternate additional triggers are not discussed in this
document. document.
This proposal does not include all operations needed for the This proposal does not include all operations needed for the
maintenance of DNSSEC key material, specifically the initial maintenance of DNSSEC key material, specifically the initial
introduction or complete removal of all keys. Because of this, introduction or complete removal of all keys. Because of this,
alternate communications mechanisms must always exist, potentially alternate communications mechanisms must always exist, potentially
introducing more complexity. introducing more complexity.
1.1. Terminology 1.1. Terminology
The terminology we use is defined in this section. The terminology we use is defined in this section. The highlighted
roles are as follows:
Highlighted roles:
o Child: "The entity on record that has the delegation of the domain o Child: The entity on record that has the delegation of the domain
from the parent" from the Parent.
o Parent: "The domain in which the child is registered" o Parent: The domain in which the Child is registered.
o Child DNS Operator: "The entity that maintains and publishes the o Child DNS Operator: The entity that maintains and publishes the
zone information for the child DNS" zone information for the Child DNS.
o Parental Agent: "The entity that the child has relationship with, o Parental Agent: The entity that the Child has a relationship with
to change its delegation information" to change its delegation information.
o Provisioning system: "A system that the operator of the master DNS o Provisioning System: A system that the Operator of the master DNS
server operates to maintain the information published in the DNS. server operates to maintain the information published in the DNS.
This includes the systems that sign the DNS data" This includes the systems that sign the DNS data.
o CDS/CDNSKEY: This notation refers to CDS and/or CDNSKEY, i.e., one
or both.
1.2. Requirements Notation 1.2. 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", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119]. [RFC2119].
2. Background 2. Background
2.1. DNS Delegations 2.1. DNS Delegations
DNS operation consists of delegations of authority. For each DNS operation consists of delegations of authority. For each
delegation there are (most of the time) two parties: the parent and delegation, there are (most of the time) two parties: the Parent and
the child. the Child.
The parent publishes information about the delegations to the child; The Parent publishes information about the delegations to the Child;
for the name servers it publishes an NS [RFC1035] RRset that lists a for the name servers, it publishes an NS [RFC1035] Resource Record
hint for name servers that are authoritative for the child. The Set (RRset) that lists a hint for name servers that are authoritative
child also publishes a NS RRset, and this set is the authoritative for the Child. The Child also publishes an NS RRset, and this set is
list of name servers to the child zone. the authoritative list of name servers to the Child zone.
The second RRset the parent sometimes publishes is the DS [RFC4034] The second RRset the Parent sometimes publishes is the DS [RFC4034]
set. The DS RRset provides information about the DNSKEY(s) that the set. The DS RRset provides information about the DNSKEY(s) that the
child has told the parent it will use to sign its DNSKEY RRset. In Child has told the Parent it will use to sign its DNSKEY RRset. In
DNSSEC trust relationship between zones is provided by the following DNSSEC, a trust relationship between zones is provided by the
chain: following chain:
parent DNSKEY --> DS --> child DNSKEY. Parent DNSKEY --> DS --> Child DNSKEY.
A prior proposal [I-D.auto-cpsync] suggested that the child send an A prior proposal [AUTO-CPSYNC] suggested that the Child send an
"update" to the parent via a mechanism similar to Dynamic Update. "update" to the Parent via a mechanism similar to DNS UPDATE. The
The main issue became: How does the child find the actual parental main issue became: how does the Child find the actual Parental Agent/
agent/server to send the update to? While that could have been server to send the update to? While that could have been solved via
solved via technical means, it failed to reach consensus. There is technical means, it failed to reach consensus. There is also a
also a similar proposal in [I-D.parent-zones]. similar proposal in [PARENT-ZONES].
As the DS record can only be present at the parent ( [RFC4034]), some As the DS record can only be present at the Parent [RFC4034], some
other method is needed to automate which DNSKEYs are picked to be other method is needed to automate which DNSKEYs are picked to be
represented in the parent zone's DS records. One possibility is to represented in the Parent zone's DS records. One possibility is to
use flags in the DNSKEY record. If the SEP bit is set, this use flags in the DNSKEY record. If the Secure Entry Point (SEP) bit
indicates that the DNSKEY is intended for use as a secure entry is set, this indicates that the DNSKEY is intended for use as a
point. This DNSKEY signs the DNSKEY RRset, and the Parental Agent secure entry point. This DNSKEY signs the DNSKEY RRset, and the
can calculate DS records based on that. But this fails to meet some Parental Agent can calculate DS records based on that. But this
operating needs, including the child having no influence what DS fails to meet some operating needs, including the Child having no
digest algorithms are used and DS records can only be published for influence on what DS digest algorithms are used and DS records that
keys that are in the DNSKEY RRset, and thus this technique would not can only be published for keys that are in the DNSKEY RRset; thus,
be compatible with Double-DS ( [RFC6781] ) key rollover. this technique would not be compatible with Double-DS rollover
[RFC6781].
2.2. Relationship Between Parent and Child DNS Operator 2.2. Relationship between Parent and Child DNS Operators
In practical application, there are many different relationships In practical application, there are many different relationships
between the parent and Child DNS Operators. The type of relationship between the Parent and Child DNS Operators. The type of relationship
affects how the Child DNS Operator communicates with the parent. affects how the Child DNS Operator communicates with the Parent.
This section will highlight some of the different situations, but is
This section will highlight some of the different situations but is
by no means a complete list. by no means a complete list.
Different communication paths: Different communication paths:
o Direct/API: The child can change the delegation information via o Direct/API: The Child can change the delegation information via
automated/scripted means. EPP[RFC5730], used by many TLDs is an automated/scripted means. The Extensible Provisioning Protocol
(EPP) [RFC5730], used by many Top-Level Domains (TLDs), is an
example of this. Other examples are web-based programmatic example of this. Other examples are web-based programmatic
interfaces that Registrars make available to their Resellers. interfaces that Registrars make available to their Resellers.
o User Interface: The Child uses a (web) site set up by the Parental o User Interface: The Child uses a web site set up by the Parental
Agent for updating delegation information. Agent for updating delegation information.
o Indirect: The communication has to be transmitted via out-of-band o Indirect: The communication has to be transmitted via an out-of-
between two parties, such as by email or telephone. This is band mechanism between two parties, such as by email or telephone.
common when the Child's DNS operator is neither the child itself This is common when the Child DNS Operator is neither the Child
nor the Registrar for the domain but a third party. itself nor the Registrar for the domain, but a third party.
o Multi-step Combinations: The information flows through an o Multi-step Combinations: The information flows through an
intermediary. It is possible, but unlikely, that all the steps intermediary. It is possible, but unlikely, that all the steps
are automated via API's and there are no humans involved. are automated via APIs and there are no humans involved.
A domain name holder (Child) may operate its own DNS servers or A domain name holder (Child) may operate its own DNS servers or
outsource the operation. While we use the word parent as a singular, outsource the operation. While we use the word "Parent" as singular,
parent can consist of single entity or a composite of many discrete a Parent can consist of a single entity or a composite of many
parts that have rules and roles. We refer to the entity that the discrete parts that have rules and roles. We refer to the entity
child corresponds with as the Parent. that the Child corresponds with as the Parent.
An organization (such as an enterprise) may delegate parts of its An organization (such as an enterprise) may delegate parts of its
name-space to be operated by a group that is not the same as that name-space to be operated by a group that is not the same as that
which operates the organization's DNS servers. In some of these which operates the organization's DNS servers. In some of these
cases the flow of information is handled in either an ad hoc manner cases, the flow of information is handled either in an ad hoc manner
or via some corporate mechanism; this can range from email to fully- or via some corporate mechanism; this can range from email to a fully
automated operation. automated operation.
2.2.1. Solution Space 2.2.1. Solution Space
This document is aimed at the cases in which there is a separation This document is aimed at the cases in which there is a separation
between the child and parent. between the Child and Parent.
A further complication is when the Child DNS Operator is not the A further complication is when the Child DNS Operator is not the
Child. There are two common cases of this: Child. There are two common cases of this:
a) The Parental Agent (e.g. registrar) handles the DNS operation. a) The Parental Agent (e.g., Registrar) handles the DNS operation.
b) A third party takes care of the DNS operation. b) A third party takes care of the DNS operation.
If the Parental Agent is the DNS operator, life is much easier; the If the Parental Agent is the DNS Operator, life is much easier; the
Parental Agent can inject any delegation changes directly into the Parental Agent can inject any delegation changes directly into the
Parent's Provisioning system. The techniques described below are not Parent's provisioning system. The techniques described below are not
needed in the case when Parental Agent is the DNS operator. needed in the case when the Parental Agent is the DNS Operator.
In the case of a third party DNS operator, the Child either needs to In the case of a third-party DNS Operator, the Child either needs to
relay changes in DNS delegation or give the Child DNS Operator access relay changes in DNS delegation or give the Child DNS Operator access
to its delegation/registration account. to its delegation/registration account.
Some parents want the child to express their DNSKEYs in the form of Some Parents want the Child to express their DNSKEYs in the form of
DS records, while others want to receive the DNSKEY records and DS records, while others want to receive the DNSKEY records and
calculate the DS records themselves. There is no consensus on which calculate the DS records themselves. There is no consensus on which
method is better; both have good reasons to exist. This solution is method is better; both have good reasons to exist. This solution is
DS vs DNSKEY agnostic, and allows operation with either. DS vs. DNSKEY agnostic and allows operation with either.
2.2.2. DNSSEC key change process 2.2.2. DNSSEC Key Change Process
After a Child DNS Operator first signs the zone, there is a need to After a Child DNS Operator first signs the zone, there is a need to
interact with the Parent, for example via a delegation account interact with the Parent, for example, via a delegation account
interface, to "upload / paste-in the zone's DS information". This interface to upload or paste in the zone's DS information. This
action of logging in through the delegation account user interface action of logging in through the delegation account user interface
authenticates that the user is authorized to change delegation authenticates that the user is authorized to change delegation
information for the child published in the parent zone. In the case information for the Child published in the Parent zone. In the case
where the Child DNS Operator does not have access to the registration where the Child DNS Operator does not have access to the registration
account, the Child needs to perform the action. account, the Child needs to perform the action.
At a later date, the Child DNS Operator may want to publish a new DS At a later date, the Child DNS Operator may want to publish a new DS
record in the parent, either because they are changing keys, or record in the Parent, either because they are changing keys or
because they want to publish a stand-by key. This involves because they want to publish a standby key. This involves performing
performing the same process as before. Furthermore when this is a the same process as before. Furthermore, when this is a manual
manual process with cut and paste, operational mistakes will happen process with cut and paste, operational mistakes will happen -- or
-- or worse, the update action is not performed at all. worse, the update action will not be performed at all.
The Child DNS Operator may also introduce new keys, and can do so The Child DNS Operator may also introduce new keys and can do so when
when old keys exist and can be used. The Child may also remove old old keys exist and can be used. The Child may also remove old keys,
keys, but this document does not support removing all keys. This is but this document does not support removing all keys. This is to
to avoid making signed zones unsigned. The Child may not enroll the avoid making signed zones unsigned. The Child may not enroll the
initial key or introduce a new key when there are no old keys that initial key or introduce a new key when there are no old keys that
can be used (without some additional, out of band, validation of the can be used (without some additional out-of-band validation of the
keys), because there is no way to validate the information. keys) because there is no way to validate the information.
3. CDS / CDNSKEY (Child DS / Child DNSKEY) Record Definitions 3. CDS (Child DS) and CDNSKEY (Child DNSKEY) Record Definitions
This document specifies two new DNS resource records, CDS and This document specifies two new DNS resource records, CDS and
CDNSKEY. These records are used to convey, from one zone to its CDNSKEY. These records are used to convey, from one zone to its
parent, the desired contents of the zone's DS resource record set Parent, the desired contents of the zone's DS resource record set
residing in the parent zone. residing in the Parent zone.
The CDS / CDNSKEY resource records are published in the child zone The CDS and CDNSKEY resource records are published in the Child zone
and gives the child control of what is published for it in the and give the Child control of what is published for it in the
parental zone. The child can publish these manually, or they can be parental zone. The Child can publish these manually, or they can be
automatically maintained by DNS provisioning tools. The CDS / automatically maintained by DNS provisioning tools. The CDS/CDNSKEY
CDNSKEY RRset expresses what the child would like the DS RRset to RRset expresses what the Child would like the DS RRset to look like
look like after the change; it is a "replace" operation, and it is up after the change; it is a "replace" operation, and it is up to the
to the software that consumes the records to translate that into the software that consumes the records to translate that into the
appropriate add/delete operations in the provisioning systems (and in appropriate add/delete operations in the provisioning systems (and in
the case of CDNSKEY, to generate the DS from the DNSKEY). If no CDS the case of CDNSKEY, to generate the DS from the DNSKEY). If neither
/ CDNSKEY RRset is present in child, this means that no change is CDS nor CDNSKEY RRset is present in the Child, this means that no
needed. change is needed.
[[RFC Editor: Please remove this paragraph before publication]
Version -04 of the ID that became this working group document
(http://tools.ietf.org/id/draft-kumari-ogud-dnsop-cds-04.txt) defined
a new record (CTA) that could hold either a DS or a DNSKEY record
(with a selector to differentiate between them). In a shocking
development, there was almost full consensus that this was horrid :-)
]
3.1. CDS Resource Record Format 3.1. CDS Resource Record Format
The wire and presentation format of the CDS ("Child DS") resource The wire and presentation format of the Child DS (CDS) resource
record is identical to the DS record [RFC4034]. IANA has allocated record is identical to the DS record [RFC4034]. IANA has allocated
RR code 59 for the CDS resource record via expert review RR code 59 for the CDS resource record via Expert Review
[I-D.ds-publish]. The CDS RR uses the same registries as DS for its [DNS-TRANSPORT]. The CDS RR uses the same registries as DS for its
fields. fields.
No special processing is performed by authoritative servers or by No special processing is performed by authoritative servers or by
resolvers, when serving or resolving. For all practical purposes CDS resolvers, when serving or resolving. For all practical purposes,
is a regular RR type. CDS is a regular RR type.
3.2. CDNSKEY Resource Record Format 3.2. CDNSKEY Resource Record Format
The wire and presentation format of the CDNSKEY ("Child DNSKEY") The wire and presentation format of the CDNSKEY ("Child DNSKEY")
resource record is identical to the DNSKEY record. IANA has resource record is identical to the DNSKEY record. IANA has
allocated RR code TBA1 for the CDNSKEY resource record via expert allocated RR code 60 for the CDNSKEY resource record via Expert
review. The CDNSKEY RR uses the same registries as DNSKEY for its Review. The CDNSKEY RR uses the same registries as DNSKEY for its
fields. fields.
No special processing is performed by authoritative servers or by No special processing is performed by authoritative servers or by
resolvers, when serving or resolving. For all practical purposes resolvers, when serving or resolving. For all practical purposes,
CDNSKEY is a regular RR type. CDNSKEY is a regular RR type.
4. Automating DS Maintenance With CDS / CDNSKEY records 4. Automating DS Maintenance with CDS/CDNSKEY Records
CDS / CDNSKEY resource records are intended to be "consumed" by CDS/CDNSKEY resource records are intended to be "consumed" by
delegation trust maintainers. The use of CDS / CDNSKEY is OPTIONAL. delegation trust maintainers. The use of CDS/CDNSKEY is OPTIONAL.
If the child publishes either the CDS or the CDNSKEY resource record, If the Child publishes either the CDS or the CDNSKEY resource record,
it SHOULD publish both. If the child knows which the parent it SHOULD publish both. If the Child knows which the Parent
consumes, it MAY choose to only publish that record type (for consumes, it MAY choose to only publish that record type (for
example, some children wish the parent to publish a DS, but they wish example, some Children wish the Parent to publish a DS, but they wish
to keep the DNSKEY "hidden" until needed). If the child publishes to keep the DNSKEY "hidden" until needed). If the Child publishes
both, the two RRsets MUST match in content. both, the two RRsets MUST match in content.
4.1. CDS / CDNSKEY Processing Rules 4.1. CDS and CDNSKEY Processing Rules
If there are no CDS / CDNSKEY RRset in the child, this signals that If there is neither CDS nor CDNSKEY RRset in the Child, this signals
no change should be made to the current DS set. This means that, that no change should be made to the current DS set. This means
once the child and parent are in sync, the Child DNS Operator MAY that, once the Child and Parent are in sync, the Child DNS Operator
remove all CDS and CDNSKEY resource records from the zone. The Child MAY remove all CDS and CDNSKEY resource records from the zone. The
DNS Operator may choose to do this to decrease the size of the zone, Child DNS Operator may choose to do this to decrease the size of the
or to decrease the workload for the parent (if the parent receives no zone or to decrease the workload for the Parent (if the Parent
CDS / CDNSKEY records it can go back to sleep). If it does receive a receives no CDS/CDNSKEY records, it can go back to sleep). If it
CDS or CDNSKEY RRset it needs to check them against what is currently does receive a CDS or CDNSKEY RRset, it needs to check them against
published - see Section 5. what is currently published (see Section 5).
Following acceptance rules are placed on the CDS / CDNSKEY resource The following acceptance rules are placed on the CDS and CDNSKEY
records as follows: resource records as follows:
o Location: the CDS / CDNSKEY resource records MUST be at the child o Location: MUST be at the Child zone apex.
zone apex.
o Signer: MUST be signed with a key that is represented in both the o Signer: MUST be signed with a key that is represented in both the
current DNSKEY and DS RRsets (unless the parent uses the CDS / current DNSKEY and DS RRsets, unless the Parent uses the CDS or
CDNSKEY RRset for initial enrollment, in that case the parent CDNSKEY RRset for initial enrollment; in that case, the Parent
validates the CDS / CDNSKEY through some other means (see validates the CDS/CDNSKEY through some other means (see
Section 6.1 and the Security Considerations.) Section 6.1 and the Security Considerations).
o Continuity: MUST NOT break the current delegation if applied to DS o Continuity: MUST NOT break the current delegation if applied to DS
RRset. RRset.
If any these conditions fail the CDS / CDNSKEY resource record MUST If any these conditions fail, the CDS or CDNSKEY resource record MUST
be ignored, and this error SHOULD be logged. be ignored, and this error SHOULD be logged.
5. CDS / CDNSKEY Publication 5. CDS/CDNSKEY Publication
The Child DNS Operator publishes CDS and / or CDNSKEY resource The Child DNS Operator publishes CDS/CDNSKEY RRset(s). In order to
records. In order to be valid, the CDS / CDNSKEY RRset MUST be be valid, the CDS/CDNSKEY RRset(s) MUST be compliant with the rules
compliant with the rules in Section 4.1. When the Parent DS is "in in Section 4.1. When the Parent DS is in sync with the CDS/CDNSKEY
sync" with the CDS / CDNSKEY resource records, the Child DNS Operator RRset(s), the Child DNS Operator MAY delete the CDS/CDNSKEY RRset(s);
MAY delete the CDS / CDNSKEY record(s); the child can determine if the Child can determine if this is the case by querying for DS
this is the case by querying for DS records in the parent records in the Parent.
6. Parent Side CDS / CDNSKEY Consumption 6. Parent-Side CDS/CDNSKEY Consumption
The CDS / CDNSKEY RRset SHOULD be used by the Parental Agent to The CDS/CDNSKEY RRset(s) SHOULD be used by the Parental Agent to
update the DS RRset in the parent zone. The Parental Agent for this update the DS RRset in the Parent zone. The Parental Agent for this
uses a tool that understands the CDS / CDNSKEY signing rules from uses a tool that understands the CDS/CDNSKEY signing rules in
Section 4.1 so it might not be able to use a standard validator. Section 4.1, so it might not be able to use a standard validator.
The parent MUST choose to use either CDNSKEY or CDS resource records The Parent MUST choose to use either CDNSKEY or CDS resource records
as their default updating mechanism. The parent MAY only accept as its default updating mechanism. The Parent MAY only accept either
either CDNSKEY or CDS, but it MAY also accept both, so it can use the CDNSKEY or CDS, but it MAY also accept both so it can use the other
other in the absence of the default updating mechanism, but it MUST in the absence of the default updating mechanism; it MUST NOT expect
NOT expect there to be both. there to be both.
6.1. Detecting a Changed CDS / CDNSKEY 6.1. Detecting a Changed CDS/CDNSKEY
How the Parental Agent gets the CDS / CDNSKEY RRset may differ, below How the Parental Agent gets the CDS/CDNSKEY RRset may differ. Below
are two examples as how this can take place. are two examples of how this can take place.
Polling The Parental Agent operates a tool that periodically checks Polling: The Parental Agent operates a tool that periodically checks
each of the children that has a DS record to see if there is a each of the Children that has a DS record to see if there is a
CDS or CDNSKEY RRset. CDS or CDNSKEY RRset.
Pushing The delegation user interface has a button {Fetch DS} when Pushing: The delegation user interface has a button {Fetch DS} that,
pushed performs the CDS / CDNSKEY processing. If the Parent when pushed, performs the CDS/CDNSKEY processing. If the
zone does not contain DS for this delegation then the "push" Parent zone does not contain DS for this delegation, then the
SHOULD be ignored. If the Parental Agent displays the contents "push" SHOULD be ignored. If the Parental Agent displays the
of the CDS / CDSNKEY to the user and gets confirmation that contents of the CDS/CDNSKEY to the user and gets confirmation
this represents their key, the Parental Agent MAY use this for that this represents their key, the Parental Agent MAY use this
initial enrollment (when the Parent zone does not contain the for initial enrollment (when the Parent zone does not contain
DS for this delegation). the DS for this delegation).
In either case the Parental Agent MAY apply additional rules that In either case, the Parental Agent MAY apply additional rules that
defer the acceptance of a CDS / CDNSKEY change, these rules may defer the acceptance of a CDS/CDNSKEY change. These rules may
include a condition that the CDS / CDNSKEY remains in place and valid include a condition that the CDS/CDNSKEY remains in place and valid
for some time period before it is accepted. It may be appropriate in for some time period before it is accepted. It may be appropriate in
the "Pushing" case to assume that the Child is ready and thus accept the "Pushing" case to assume that the Child is ready and thus accept
changes without delay. changes without delay.
6.1.1. CDS / CDNSKEY Polling 6.1.1. CDS/CDNSKEY Polling
This is the only defined use of CDS / CDNSKEY resource records in This is the only defined use of CDS/CDNSKEY resource records in this
this document. There are limits to the scalability of polling document. There are limits to the scalability of polling techniques;
techniques, thus some other mechanism is likely to be specified later thus, some other mechanism is likely to be specified later that
that addresses CDS / CDNSKEY resource record usage in the situation addresses CDS/CDNSKEY resource record usage in the situation where
where polling does not scale to. Having said that, Polling will work polling runs into scaling issues. Having said that, polling will
in many important cases such as enterprises, universities and smaller work in many important cases such as enterprises, universities, and
TLDs. In many regulatory environments the registry is prohibited smaller TLDs. In many regulatory environments, the Registry is
from talking to the registrant. In most of these cases the prohibited from talking to the Registrant. In most of these cases,
registrant has a business relationship with the registrar, and so the the Registrant has a business relationship with the Registrar, so the
registrar can offer this as a service. Registrar can offer this as a service.
If the CDS / CDNSKEY RRset does not exist, the Parental Agent MUST If the CDS/CDNSKEY RRset(s) do not exist, the Parental Agent MUST
take no action. Specifically it MUST NOT delete or alter the take no action. Specifically, it MUST NOT delete or alter the
existing DS RRset. existing DS RRset.
6.1.2. Polling Triggers 6.1.2. Polling Triggers
It is assumed that other mechanisms will be implemented to trigger It is assumed that other mechanisms will be implemented to trigger
the parent to look for an updated CDS / CDNSKEY RRsets. As the CDS / the Parent to look for an updated CDS/CDNSKEY RRset. As the CDS/
CDNSKEY resource records are validated with DNSSEC, these mechanisms CDNSKEY resource records are validated with DNSSEC, these mechanisms
can be unauthenticated. As an example, a child could telephone its can be unauthenticated. As an example, a Child could telephone its
parent and request that they process the new CDS or CDNSKEY resource Parent and request that it process the new CDS or CDNSKEY resource
records or an unauthenticated POST could be made to a webserver (with records, or an unauthenticated POST could be made to a web server
rate-limiting). (with rate-limiting).
Other documents can specify the trigger conditions. Other documents can specify the trigger conditions.
6.2. Using the New CDS / CDNSKEY Records 6.2. Using the New CDS/CDNSKEY Records
Regardless of how the Parental Agent detected changes to a CDS / Regardless of how the Parental Agent detected changes to a CDS/
CDNSKEY RRset, the Parental Agent SHOULD use a DNSSEC validator to CDNSKEY RRset, the Parental Agent SHOULD use a DNSSEC validator to
obtain a validated CDS / CDNSKEY RRset from the Child zone. A NOT obtain a validated CDS/CDNSKEY RRset from the Child zone. A NOT
RECOMMENDED exception to this is if the parent performs some RECOMMENDED exception to this is if the Parent performs some
additional validation on the data to confirm that it is the "correct" additional validation on the data to confirm that it is the "correct"
key. key.
The Parental Agent MUST ensure that previous versions of the CDS / The Parental Agent MUST ensure that previous versions of the CDS/
CDNSKEY RRset do not overwrite more recent versions. This MAY be CDNSKEY RRset do not overwrite more recent versions. This MAY be
accomplished by checking that the signature inception in the RRSIG accomplished by checking that the signature inception in the Resource
for CDS / CDNSKEY RRset is later and / or the serial number on the Record Signature (RRSIG) for CDS/CDNSKEY RRset is later and/or that
child's SOA is greater. This may require the Parental Agent to the serial number on the Child's Start of Authority (SOA) is greater.
maintain some state information. This may require the Parental Agent to maintain some state
information.
The Parental Agent MAY take extra security measures. For example, to The Parental Agent MAY take extra security measures. For example, to
mitigate the possibility that a Child's key signing key has been mitigate the possibility that a Child's Key Signing Key (KSK) has
compromised, the Parental Agent may, for example, inform (by email or been compromised, the Parental Agent may inform (by email or other
other methods) the Child DNS Operator of the change. However the methods) the Child DNS Operator of the change. However, the precise
precise out-of-band measures that a parent zone takes are outside the out-of-band measures that a Parent zone takes are outside the scope
scope of this document. of this document.
Once the Parental Agent has obtained a valid CDS / CDNSKEY RRset it Once the Parental Agent has obtained a valid CDS/CDNSKEY RRset it
MUST check the publication rules from section 4.1. In particular the MUST check the publication rules from Section 4.1. In particular,
Parental Agent MUST check the Continuity rule and do its best not to the Parental Agent MUST check the Continuity rule and do its best not
invalidate the Child zone. Once checked and if the information in to invalidate the Child zone. Once checked, if the information in
the CDS / CDNSKEY and DS differ it may apply the changes to the the CDS/CDNSKEY and DS differ, it may apply the changes to the Parent
parent zone. If the parent consumes CDNSKEY, the parent should zone. If the Parent consumes CDNSKEY, the Parent should calculate
calculate the DS before doing this comparison. the DS before doing this comparison.
6.2.1. Parent Calculates DS 6.2.1. Parent Calculates DS
There are cases where the Parent wants to calculate the DS record due There are cases where the Parent wants to calculate the DS record due
to policy reasons. In this case, the Child publishes CDNSKEY records to policy reasons. In this case, the Child publishes CDNSKEY
and the parent calculates the DS records on behalf of the children. records, and the Parent calculates the DS records on behalf of the
Children.
When a Parent operates in "calculate DS" mode it can operate in one When a Parent operates in "calculate DS" mode, it can operate in one
of two sub-modes: of two sub-modes:
full: it only publishes DS records it calculates from DNSKEY full: The Parent only publishes DS records it calculates from DNSKEY
records, records.
augment: it will make sure there are DS records for the digest augment: The Parent will make sure there are DS records for the
algorithm(s) it requires(s). digest algorithm(s) it requires(s).
In the case where the parent fetches the CDNSKEY RRset and calculates In the case where the Parent fetches the CDNSKEY RRset and calculates
the DS the resulting DS can differ from the CDS published by the the DS, the resulting DS can differ from the CDS published by the
child. It is expected that the differences are only due different Child. It is expected that the differences are only due to the
set of digest algorithms used. different set of digest algorithms used.
7. IANA Considerations 7. IANA Considerations
IANA has assigned RR Type code 59 for the CDS resource record. This IANA has assigned RR Type code 59 for the CDS resource record. This
was done for an earlier version of this document[I-D.ds-publish] This was done for a draft version whose content was later incorporated
document is to become the reference for CDS RRtype. into this document [DNS-TRANSPORT]. This document is the reference
for CDS RRtype.
IANA is requested to assign an RR Type for the CDNSKEY, see below IANA has assigned an RR Type for the CDNSKEY as described below:
Type: CDNSKEY Type: CDNSKEY
Value: TBD1 (60 suggested) Value: 60
Meaning: DNSKEY(s) the child wants reflected in DS Meaning: DNSKEY(s) the Child wants reflected in DS
Reference: This document Reference: This document
8. Privacy Considerations 8. Privacy Considerations
All of the information handled / transmitted by this protocol is All of the information handled or transmitted by this protocol is
public information published in the DNS. public information published in the DNS.
9. Security Considerations 9. Security Considerations
This work is for the normal case; when things go wrong there is only This work is for the normal case; when things go wrong there is only
so much that automation can fix. so much that automation can fix.
If child breaks DNSSEC validation by removing all the DNSKEYs that If the Child breaks DNSSEC validation by removing all the DNSKEYs
are represented in the DS set its only repair actions are to contact that are represented in the DS set, its only repair actions are to
the parent or restore the DNSKEYs in the DS set. contact the Parent or restore the DNSKEYs in the DS set.
In the event of a compromise of the server or system generating In the event of a compromise of the server or system generating
signatures for a zone, an attacker might be able to generate and signatures for a zone, an attacker might be able to generate and
publish new CDS / CDNSKEY resource records. The modified CDS / publish new CDS/CDNSKEY resource records. The modified CDS/CDNSKEY
CDNSKEY records will be picked up by this technique and so may allow records will be picked up by this technique and may allow the
the attacker to extend the effective time of his attack. If there is attacker to extend the effective time of his attack. If there is a
a delay in accepting changes to DS, as in [RFC5011], then the delay in accepting changes to DS, as in [RFC5011], then the attacker
attacker needs to hope his activity is not detected before the DS in needs to hope his activity is not detected before the DS in the
the parent is changed. If this type of change takes place, the child Parent is changed. If this type of change takes place, the Child
needs to contact the parent (possibly via a registrar web interface) needs to contact the Parent (possibly via a Registrar web interface)
and remove any compromised DS keys. and remove any compromised DS keys.
A compromise of the account with the parent (e.g. registrar) will not A compromise of the account with the Parent (e.g., Registrar) will
be mitigated by this technique, as the "new registrant" can delete / not be mitigated by this technique, as the "new Registrant" can
modify the DS records at will. delete or modify the DS records at will.
While it may be tempting, this SHOULD NOT be used for initial While it may be tempting, the techniques specified in this document
enrollment of keys since there is no way to ensure that the initial SHOULD NOT be used for initial enrollment of keys since there is no
key is the correct one. If is used, strict rules for inclusion of way to ensure that the initial key is the correct one. If it is
keys such as hold down times, challenge data inclusion or similar, used, strict rules for inclusion of keys -- such as hold-down times,
MUST be used, along with some kind of challenge mechanism. A child challenge data inclusion, or similar -- MUST be used along with some
cannot use this mechanism to go from signed to unsigned (publishing kind of challenge mechanism. A Child cannot use this mechanism to go
an empty CDS / CDNSKEY RRset means no-change should be made in the from signed to unsigned (publishing an empty CDS/CDNSKEY RRset means
parent). no change should be made in the Parent).
The CDS RR type should allow for enhanced security by simplifying The CDS RR type should allow for enhanced security by simplifying the
process. Since key change is automated, updating a DS RRset by other process. Since key change is automated, updating a DS RRset by other
means may be regarded as unusual and subject to extra security means may be regarded as unusual and subject to extra security
checks. checks.
As this introduces a new mechanism to update information in the As this introduces a new mechanism to update information in the
parent it MUST be clear who is fetching the records and creating the Parent, it MUST be clear who is fetching the records and creating the
appropriate records in the parent zone. Specifically some operations appropriate records in the Parent zone. Specifically, some
may use other mechanisms than what is described here. For example, a operations may use mechanisms other than what is described here. For
registrar may assume that it is maintaining the DNSSEC key example, a Registrar may assume that it is maintaining the DNSSEC key
information in the registry, and may have this cached. If the information in the Registry and may have this cached. If the
registry is fetching the CDS / CDNSKEY RRset then the registry and Registry is fetching the CDS/CDNSKEY RRset, then the Registry and
registrar may have different views of the DNSSEC key material and the Registrar may have different views of the DNSSEC key material; the
result of such a situation is unclear. Therefore, this mechanism result of such a situation is unclear. Therefore, this mechanism
SHOULD NOT be use to bypass intermediaries that might cache SHOULD NOT be used to bypass intermediaries that might cache
information and because of that get the wrong state. information and, because of that, get the wrong state.
If there is a failure in applying changes in the child zone to all If there is a failure in applying changes in the Child zone to all
DNS servers listed in either parent or child NS set it is possible DNS servers listed in either Parent or Child NS set, it is possible
that the Parental agent may get confused, either because it gets that the Parental Agent may get confused either because it gets
different answers on different checks or CDS RR validation fails. In different answers on different checks or CDS RR validation fails. In
the worst case, the Parental Agent performs an action reversing a the worst case, the Parental Agent performs an action reversing a
prior action but after the child signing system decides to take the prior action after the Child signing system decides to take the next
next step in the key change process, resulting in a broken step in the key change process, resulting in a broken delegation.
delegation.
DNS is a loosely coherent distributed database with local caching; DNS is a loosely coherent distributed database with local caching;
therefore, it is important to allow old information to expire from therefore, it is important to allow old information to expire from
caches before deleting DS or DNSKEY records. Similarly, it is caches before deleting DS or DNSKEY records. Similarly, it is
important to allow new records to propagate through the DNS before important to allow new records to propagate through the DNS before
use, see [RFC6781]. use (see [RFC6781]).
It is common practice for users to outsource their DNS hosting to a It is common practice for users to outsource their DNS hosting to a
third-party DNS provider. In order for that provider to be able to third-party DNS provider. In order for that provider to be able to
maintain the DNSSEC information some users give the provider their maintain the DNSSEC information, some users give the provider their
registrar login credentials (which obviously has negative security Registrar login credentials (which obviously has negative security
implications). Deploying the solution described in this document implications). Deploying the solution described in this document
allows the 3rd party DNS provider to maintain the DNSSEC information allows third-party DNS providers to maintain the DNSSEC information
without giving them the registrar credentials, thereby improving without Registrants giving their Registrar credentials, thereby
security. improving security.
By automating the maintenance of the DNSSEC key information (and By automating the maintenance of the DNSSEC key information (and
removing humans from the process), we expect to decrease the number removing humans from the process), we expect to decrease the number
of DNSSEC related outages, which should increase DNSSEC deployment. of DNSSEC related outages, which should increase DNSSEC deployment.
10. Acknowledgements 10. Acknowledgements
We would like to thank a large number of folk, including: Mark We would like to thank a large number of folk, including Mark
Andrews, Joe Abley, Jaap Akkerhuis, Roy Arends, Doug Barton, Brian Andrews, Joe Abley, Jaap Akkerhuis, Roy Arends, Doug Barton, Brian
Dickson, Paul Ebersman, Tony Finch, Jim Galvin, Paul Hoffman, Samir Dickson, Paul Ebersman, Tony Finch, Jim Galvin, Paul Hoffman, Samir
Hussain, Tatuya Jinmei, Olaf Kolkman, Stephan Lagerholm, Cricket Liu, Hussain, Tatuya Jinmei, Olaf Kolkman, Stephan Lagerholm, Cricket Liu,
Matt Larson, Marco Sanz, Antoin Verschuren, Suzanne Woolf, Paul Matt Larson, Marco Sanz, Antoin Verschuren, Suzanne Woolf, Paul
Wouters, John Dickinson, Timothe Litt and Edward Lewis. Wouters, John Dickinson, Timothe Litt, and Edward Lewis.
Special thanks to Wes Hardaker for contributing significant text and Special thanks to Wes Hardaker for contributing significant text and
creating the complementary (CSYNC) solution, and to Patrik Faltstrom, creating the complementary (CSYNC) solution, and to Patrik Faltstrom,
Paul Hoffman, Matthijs Mekking, Mukund Sivaraman and Jeremy C. Reed Paul Hoffman, Matthijs Mekking, Mukund Sivaraman, and Jeremy C. Reed
for text and in-depth review. Brian Carpender provided a good Gen- for text and in-depth review. Brian Carpenter provided a good
Art review. Gen-ART review.
There were a number of other folk with whom we discussed this, There were a number of other folk with whom we discussed this
apologies for not remembering everyone. document; apologies for not remembering everyone.
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
skipping to change at page 15, line 14 skipping to change at page 15, line 36
[RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC) [RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC)
Trust Anchors", STD 74, RFC 5011, September 2007. Trust Anchors", STD 74, RFC 5011, September 2007.
[RFC6781] Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC [RFC6781] Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC
Operational Practices, Version 2", RFC 6781, December Operational Practices, Version 2", RFC 6781, December
2012. 2012.
11.2. Informative References 11.2. Informative References
[I-D.auto-cpsync] [AUTO-CPSYNC]
Mekking, W., "Automated (DNSSEC) Child Parent Mekking, W., "Automated (DNSSEC) Child Parent
Synchronization using DNS UPDATE", draft-mekking-dnsop- Synchronization using DNS UPDATE", Work in Progress,
auto-cpsync-01 (work in progress), December 2010. December 2010.
[I-D.csync] [CPSYNC-DNS]
Hardaker, W., "Child To Parent Synchronization in DNS", Hardaker, W., "Child To Parent Synchronization in DNS",
draft-hardaker-dnsop-csync-02 (work in progress), July Work in Progress, July 2014.
2013.
[I-D.ds-publish] [DNS-TRANSPORT]
Barwood, G., "DNS Transport", draft-barwood-dnsop-ds- Barwood, G., "DNS Transport", Work in Progress, June 2011.
publish-02 (work in progress), June 2011.
[I-D.parent-zones] [PARENT-ZONES]
Andrews, M., "Updating Parent Zones", draft-andrews-dnsop- Andrews, M., "Updating Parent Zones", Work in Progress,
update-parent-zones-04 (work in progress), November 2013. November 2013.
[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)", [RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, August 2009. STD 69, RFC 5730, August 2009.
[RFC5910] Gould, J. and S. Hollenbeck, "Domain Name System (DNS) [RFC5910] Gould, J. and S. Hollenbeck, "Domain Name System (DNS)
Security Extensions Mapping for the Extensible Security Extensions Mapping for the Extensible
Provisioning Protocol (EPP)", RFC 5910, May 2010. Provisioning Protocol (EPP)", RFC 5910, May 2010.
Appendix A. RRR background Appendix A. RRR Background
RRR is our shorthand for Registry/Registrar/Registrant model of RRR is our shorthand for the Registry/Registrar/Registrant model of
parent child relationship. Parent-Child relationships.
In the RRR world, the different parties are frequently from different In the RRR world, the different parties are frequently from different
organizations. In the single enterprise world there are also organizations. In the single enterprise world, there are also
organizational / geographical / cultural separations that affect how organizational, geographical, and cultural separations that affect
information flows from a Child to the parent. how information flows from a Child to the Parent.
Due to the complexity of the different roles and interconnections, Due to the complexity of the different roles and interconnections,
automation of delegation information has not yet occurred. There automation of delegation information has not yet occurred. There
have been proposals to automate this, in order to improve the have been proposals to automate this, in order to improve the
reliability of the DNS. These proposals have not gained enough reliability of the DNS. These proposals have not gained enough
traction to become standards. traction to become standards.
For example in many of the TLD cases there is the RRR model For example, in many of the TLD cases, there is the RRR model
(Registry, Registrar and Registrant). The Registry operates DNS for (Registry/Registrar/Registrant). The Registry operates DNS for the
the TLD, the Registrars accept registrations and place information TLD, and the Registrars accept registrations and place information
into the Registries database. The Registrant only communicates with into the Registry's database. The Registrant only communicates with
the Registrar; frequently the Registry is not allowed to communicate the Registrar; frequently, the Registry is not allowed to communicate
with the Registrant. In that case as far as the registrant is with the Registrant. In that case, as far as the Registrant is
concerned the Registrar is the same entity as the Parent. concerned, the Registrar is the same entity as the Parent.
In many RRR cases the Registrar and Registry communicate via In many RRR cases, the Registrar and Registry communicate via EPP
EPP[RFC5730] and use the EPP DNSSEC extension [RFC5910]. In a number [RFC5730] and use the EPP DNSSEC extension [RFC5910]. In a number of
of ccTLDs there are other mechanisms in use as well as EPP, but in Country Code TLDs (ccTLDs), there are other mechanisms in use as well
general there seems to be a movement towards EPP usage when DNSSEC is as EPP, but in general, there seems to be a movement towards EPP
enabled in the TLD. usage when DNSSEC is enabled in the TLD.
Appendix B. CDS key rollover example Appendix B. CDS Key Rollover Example
This section shows an example on how CDS is used when performing a This section shows an example on how CDS is used when performing a
KSK rollover, this example will demonstrate the the double DS KSK rollover. This example will demonstrate the Double-DS rollover
rollover method from section 4.1.2 in [RFC6781]. Other rollovers method from Section 4.1.2 of [RFC6781]. Other rollovers using
using CDNSKEY and double KSK are left as an exercise to the reader. CDNSKEY and double KSK are left as an exercise to the reader. The
The table below does not reflect the ZSK keys they just do not matter table below does not reflect the Zone Signing Keys (ZSKs) as they do
during KSK rollovers. The wait states below highlight what RRset not matter during KSK rollovers. The wait steps highlight what RRset
needs to expire from caches before progressing to the next step. needs to expire from caches before progressing to the next step.
+------+---------------+---------+---------+--------------+---------+ +------+---------------+---------+---------+--------------+---------+
| Step | State | Parent | Child | DNSKEY and | Child | | Step | State | Parent | Child | DNSKEY and | Child |
| | | DS | KSK | CDS signer | CDS | | | | DS | KSK | CDS signer | CDS |
+------+---------------+---------+---------+--------------+---------+ +------+---------------+---------+---------+--------------+---------+
| | Beginning | A | A | A | | | | Beginning | A | A | A | |
| 1 | Add CDS | A | A | A | AB | | 1 | Add CDS | A | A | A | AB |
| Wait | for DS change | A | A | A | AB | | Wait | for DS change | A | A | A | AB |
| 2 | Updated DS | AB | A | A | AB | | 2 | Updated DS | AB | A | A | AB |
skipping to change at page 17, line 5 skipping to change at page 18, line 25
| | Rollover | | | | | | | Rollover | | | | |
| Wait | > DNSKEY TTL | AB | B | B | AB | | Wait | > DNSKEY TTL | AB | B | B | AB |
| 4 | Child Cleanup | AB | B | B | B | | 4 | Child Cleanup | AB | B | B | B |
| 5 | Parent cleans | B | B | B | B | | 5 | Parent cleans | B | B | B | B |
| 6 | Optional CDS | B | B | B | | | 6 | Optional CDS | B | B | B | |
| | delete | | | | | | | delete | | | | |
+------+---------------+---------+---------+--------------+---------+ +------+---------------+---------+---------+--------------+---------+
Table 1: States Table 1: States
Appendix C. Changes / Author Notes.
[RFC Editor: Please remove this section before publication ]
WG-13 to WG-14 IETF Last call and IESG processing
o Applied text fixes from Phil Pennock
o Addressed comments from Brian Carpender GEN-ART review.
o Barry Leiba wanted better IANA considerations and suggested some
text changes in 6.1 and 6.2.1
o Reformatted the Appendix B table to be clearer.
WG-12 to WG-13
o Added appendix B showing Key rollover using CDS.
WG-11 to WG-12
o Many nits and helpful grammar fixes from Jeremy C. Reed.
WG-10 to WG-11
o More useful text from Matthijs.
o Explained why the child might want to remove the CDS / CDNSKEY
Records.
WG-09 to WG-10
o Incorporated off list comments from Stephan Lagerholm. Largest
change is fixing discrepancy between parent MAY perform OOB
validation and the Signer rule in 4.1. Clarified by updating
signer rule to allow enrolment if validation is performed OOB.
WG-08 to WG-09
o New text from Paul Hoffman for the first paragraph of the intro.
o And a modification from Jaap.
WG-07 to WG-08
o Incorporated text from Antoin Verschuren at the end of Section 6.
o Comments from Paul Hoffman and Tim W
WG-06 to WG-07
o Incorporated nits / editorial comments from Tim Wicinski.
o
* Reference for Mark's draft was incorrect, Wes Hardaker doesn't
work for ISC :-P
* Normalized CDS record / CDS resource record / records / etc.
* Language cleanup / nits / poor grammar.
* removed "punted" colloquialism.
WG-05 to WG-06
o Consensus (according to me!) was that mail thread said "Child MAY
remove the CDS record". Changed to accommodate.
o "The proposal below can operate with both models, but the child
needs to be aware of the parental policies." - removed "but the
child needs to be aware of the parental policies.". This is no
longer true, as we suggest publishing both CDS and CDSNKEY.
o Added: "without some additional out of band process" to "The Child
may not enroll the initial key or introduce a new key when there
are no old keys that can be used (without some additional, out of
band, validation of the keys), because there is no way to validate
the information."
o Added a bit to the IANA section, requesting that TBA1 be replaced
with the IANA allocated code.
o Removed: "Some parents prefer to accept DNSSEC key information in
DS format, some parents prefer to accept it in DNSKEY format, and
calculate the DS record on the child's behalf. Each method has
pros and cons, both technical and policy. This solution is DS vs
DNSKEY agnostic, and allows operation with either." from Section 4
as it is covered in Section 2.2.1
o Remove a bunch of comments from the XML. I was getting tired of
scrolling past them. If the authors need them back, they are in
SVN commit 47.
WG-04 to WG-05
o More comments from Patrik, Paul and Ed.
o Many nits and fixes from Matthijs Mekking.
o Outstanding question: Should we remove the "Child SHOULD remove
the CDS record" text? Mail sent to list.
WG-03 to WG-04
o Large number of comments and changes from Patrik.
WG-02 to WG-03
o Fixed some references to RFC 5011 - from Samir Hussain.
o Fixed some spelling / typos - from Samir Hussain.
o A number of clarifications on the meaning on an empty / non-
existant CDS RRset - thanks to JINMEI, Tatuya
o Be consistent in mentioning both CDS and CDNSKEY throughout the
document.
WG-01 to WG-02
o Many nits and suggestions from Mukund.
o Matthijs: " I still think that it is too strong that the Child DNS
Operator SHOULD/MUST delete the CDS RRset when the Parent DS is
"in sync". This should be a MAY"
WG-00 to WG-01
o Addressed Vancouver: "Paul Hoffmann: NOT ready for WGLC. None of
the 2 documents explain why there is a split between the two
strategies." Thanks to Paul for providing text.
From -05 to WG-00:
o Nothing changed, resubmit under new name.
From 04 to 05
o Renamed the record back to CDS.
From 03 to 04.
o Added text explaining that CDS and CSYNC complement each other,
not replace or compete.
o Changed format of record to be <selector> <data> to allow the
publication of DS **or** DNSKEY.
o Bunch of text changed to cover the above.
o Added a bit more text on the polling scaling stuff, expectation
that other triggers will be documented.
From 02 to 03
o Applied comments by Matthijs Mekking
o Incorporated suggestions from Edward Lewis about structure
o Reworked structure to be easier for implementors to follow
o Applied many suggestions from a wonderful thorough review by John
Dickinson
o Removed the going Unsigned option
From 01 to 02
o Major restructuring to facilitate easier discussion
o Lots of comments from DNSOP mailing list incorporated, including
making draft DNSKEY/DS neutral, explain different relationships
that exists,
o added more people to acks.
o added description of enterprise situations
o Unified on using Parental Agent over Parental Representative
o Removed redundant text when possible
o Added text to explain what can go wrong if not all child DNS
servers are in sync.
o Reference prior work by Matthijs Mekking
o Added text when parent calculates DS from DNSKEY
From - to -1.
o Removed from section .1: "If a child zone has gone unsigned, i.e.
no DNSKEY and no RRSIG in the zone, the parental representative
MAY treat that as intent to go unsigned. (NEEDS DISCUSSION)."
Added new text at end. -- suggestion by Scott Rose 20/Feb/13.
o Added some background on the different DNS Delegation operating
situations and how they affect interaction of parties. This moved
some blocks of text from later sections into here.
o Number of textual improvements from Stephan Lagerholm
o Added motivation why CDS is needed in CDS definition section
o Unified terminology in the document.
o Much more background
Authors' Addresses Authors' Addresses
Warren Kumari Warren Kumari
Google Google
1600 Amphitheatre Parkway 1600 Amphitheatre Parkway
Mountain View, CA 94043 Mountain View, CA 94043
US US
Email: warren@kumari.net EMail: warren@kumari.net
Olafur Gudmundsson Olafur Gudmundsson
Shinkuro Inc. OGUD Consulting
4922 Fairmont Av, Suite 250 3821 Village Park Dr.
Bethesda, MD 20814 Chevy Chase, MD 20815
USA US
Email: ogud@ogud.com EMail: ogud@ogud.com
George Barwood George Barwood
33 Sandpiper Close 33 Sandpiper Close
Gloucester GL2 4LZ Gloucester GL2 4LZ
United Kingdom United Kingdom
Email: george.barwood@blueyonder.co.uk EMail: george.barwood@blueyonder.co.uk
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