Internet DRAFT - draft-ietf-dnsop-dns-catalog-zones
draft-ietf-dnsop-dns-catalog-zones
DNSOP Working Group P. van Dijk
Internet-Draft PowerDNS
Intended status: Standards Track L. Peltan
Expires: 11 August 2023 CZ.NIC
O. Sury
Internet Systems Consortium
W. Toorop
NLnet Labs
C.R. Monshouwer
P. Thomassen
deSEC, SSE - Secure Systems Engineering
A. Sargsyan
Internet Systems Consortium
7 February 2023
DNS Catalog Zones
draft-ietf-dnsop-dns-catalog-zones-09
Abstract
This document describes a method for automatic DNS zone provisioning
among DNS primary and secondary nameservers by storing and
transferring the catalog of zones to be provisioned as one or more
regular DNS zones.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on 11 August 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Description . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Catalog Zone Structure . . . . . . . . . . . . . . . . . . . 4
4.1. Member Zones . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Properties . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.1. Schema Version (version property) . . . . . . . . . . 6
4.3. Member Zone Properties . . . . . . . . . . . . . . . . . 7
4.3.1. Change of Ownership (coo property) . . . . . . . . . 7
4.3.2. Groups (group property) . . . . . . . . . . . . . . . 8
4.4. Custom Properties (*.ext properties) . . . . . . . . . . 9
5. Nameserver Behavior . . . . . . . . . . . . . . . . . . . . . 10
5.1. General Requirements . . . . . . . . . . . . . . . . . . 10
5.2. Member zone name clash . . . . . . . . . . . . . . . . . 11
5.3. Member zone removal . . . . . . . . . . . . . . . . . . . 11
5.4. Member node name change . . . . . . . . . . . . . . . . . 11
5.5. Migrating member zones between catalogs . . . . . . . . . 11
5.6. Zone-associated state reset . . . . . . . . . . . . . . . 12
6. Implementation and Operational Notes . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
10. Normative References . . . . . . . . . . . . . . . . . . . . 16
11. Informative References . . . . . . . . . . . . . . . . . . . 17
Appendix A. Catalog Zone Example . . . . . . . . . . . . . . . . 17
Appendix B. Implementation Status . . . . . . . . . . . . . . . 18
Appendix C. Change History . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
The content of a DNS zone is synchronized among its primary and
secondary nameservers using AXFR and IXFR. However, the list of
zones served by the primary (called a catalog in [RFC1035]) is not
automatically synchronized with the secondaries. To add or remove a
zone, the administrator of a DNS nameserver farm not only has to add
or remove the zone from the primary, they must also add/remove
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configuration for the zone from all secondaries. This can be both
inconvenient and error-prone; in addition, the steps required are
dependent on the nameserver implementation.
This document describes a method in which the list of zones is
represented as a regular DNS zone (called a "catalog zone" here), and
transferred using DNS zone transfers. When entries are added to or
removed from the catalog zone, it is distributed to the secondary
nameservers just like any other zone. Secondary nameservers can then
add/remove/modify the zones they serve in accordance with the changes
to the catalog zone. Other use-cases of nameserver remote
configuration by catalog zones are possible, where the catalog
consumer might not be a secondary.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here.
Catalog zone: A DNS zone containing a DNS catalog, that is, a list
of DNS zones and associated properties.
Member zone: A DNS zone whose configuration is published inside a
catalog zone.
Member node: A DNS name in the Catalog zone representing a Member
zone.
$CATZ: Used in examples as a placeholder to represent the domain
name of the catalog zone itself. $OLDCATZ and $NEWCATZ are used to
discuss migration of a member zone from one catalog zone $OLDCATZ
to another catalog zone $NEWCATZ.
Catalog producer: An entity that generates and is responsible for
the contents of the catalog zone.
Catalog consumer: An entity that extracts information from the
catalog zone (such as a DNS server that configures itself
according to the catalog zone's contents).
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This document makes use of terminology that is specific to the DNS,
such as for transfer mechanisms (AXFR, IXFR), for record types (SOA,
NS, PTR), and other technical terms (such as RDATA). Since these
terms have specific meanings in the DNS they are not expanded at
first use in this document. For definitions of those and other
terms, see [RFC8499].
3. Description
A catalog zone is a DNS zone whose contents are specially crafted.
Its resource records (RR) primarily constitute a list of PTR records
referencing other DNS zones (so-called "member zones"). The catalog
zone may contain other records indicating additional metadata (so-
called "properties") associated with these member zones.
Catalog consumers MUST ignore any RRs in the catalog zone for which
no processing is specified or which are otherwise not supported by
the implementation.
Authoritative servers may be pre-configured with multiple catalog
zones, each associated with a different set of configurations.
Although the contents of a catalog zone are interpreted and acted
upon by nameservers, a catalog zone is a regular DNS zone and so must
adhere to the standards for DNS zones.
A catalog zone is primarily intended for the management of a farm of
authoritative nameservers, and should not be expected to be
accessible from any recursive nameserver.
4. Catalog Zone Structure
A catalog zone MUST follow the usual rules for DNS zones. In
particular, SOA and NS record sets MUST be present and adhere to
standard requirements (such as [RFC1982]).
Although catalog zones are not intended to be queried via recursive
resolution (see Section 7), at least one NS RR is still required so
that a catalog zone is a syntactically correct DNS zone. A single NS
RR with a NSDNAME field containing the absolute name "invalid." is
RECOMMENDED [RFC2606][RFC6761].
4.1. Member Zones
The list of member zones is specified as a collection of member
nodes, represented by domain names under the owner name "zones" where
"zones" is a direct child domain of the catalog zone.
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The names of member zones are represented on the RDATA side (instead
of as a part of owner names) of a PTR record, so that all valid
domain names may be represented regardless of their length [RFC1035].
This PTR record MUST be the only record in the PTR RRset with the
same name. The presence of more than one record in the RRset
indicates a broken catalog zone which MUST NOT be processed (see
Section 5.1).
For example, if a catalog zone lists three zones "example.com.",
"example.net." and "example.org.", the member node RRs would appear
as follows:
<unique-1>.zones.$CATZ 0 IN PTR example.com.
<unique-2>.zones.$CATZ 0 IN PTR example.net.
<unique-3>.zones.$CATZ 0 IN PTR example.org.
where <unique-N> is a label that tags each record in the collection.
<unique-N> has a unique value in the collection. When different
<unique-N> labels hold the same PTR value (i.e., point to the same
member zone), the catalog zone is broken and MUST NOT be processed
(see Section 5.1).
Member node labels carry no informational meaning beyond labeling
member zones. A changed label may indicate that the state for a zone
needs to be reset (see Section 5.6).
Having the zones uniquely tagged with the <unique-N> label ensures
that additional RRs can be added below the member node (see
Section 4.2).
The CLASS field of every RR in a catalog zone MUST be IN (1). The
TTL field's value has no meaning in this context and SHOULD be
ignored.
4.2. Properties
Catalog zone information is stored in the form of "properties".
Properties are identified by their name, which is used as an owner
name prefix for one or more record sets underneath a member node (or
underneath the catalog zone apex), with RR type(s) as appropriate for
the respective property.
Known properties with the correct RR type, but which are for some
reason invalid (for example because of an impossible value or because
of an illegal number of RRs in the RRset), denote a broken catalog
zone which MUST NOT be processed (see Section 5.1).
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This document includes a set of initial properties which can be
extended via the IANA registry defined and created in Section 8.
Some properties are defined at the global level; others are scoped to
apply only to a specific member zone. This document defines a
mandatory global property in Section 4.2.1. The "zones" label from
Section 4.1 can also be seen as a global property and is listed as
such in the IANA registry in Section 8. Member-specific properties
are described in Section 4.3.
Implementers may store additional information in the catalog zone
with Custom properties, see Section 4.4. The meaning of such custom
properties is determined by the implementation in question.
4.2.1. Schema Version (version property)
The catalog zone schema version is specified by an integer value
embedded in a TXT RR named version.$CATZ. All catalog zones MUST
have a TXT RRset named version.$CATZ with exactly one RR.
Catalog consumers MUST NOT apply catalog zone processing to
* zones without the version property
* zones with a version property with more than one RR in the RRset
* zones with a version property without an expected value in the
version.$CATZ TXT RR
* zones with a version property with a schema version value which is
not implemented by the consumer (e.g. version "1")
These conditions signify a broken catalog zone which MUST NOT be
processed (see Section 5.1).
For this memo, the value of the version.$CATZ TXT RR MUST be set to
"2", i.e.:
version.$CATZ 0 IN TXT "2"
NB: Version 1 was used in a draft version of this memo and reflected
the implementation first found in BIND 9.11.
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4.3. Member Zone Properties
Each member zone MAY have one or more additional properties,
described in this chapter. The member properties described in this
document are all optional and implementations MAY choose to implement
all, some or none of them. Member zone properties are represented by
RRsets below the corresponding member node.
4.3.1. Change of Ownership (coo property)
The coo property facilitates controlled migration of a member zone
from one catalog to another.
A Change Of Ownership is signaled by the coo property in the catalog
zone currently "owning" the zone. The name of the new catalog is the
value of a PTR record in the relevant coo property in the old
catalog. For example if member "example.com." will migrate from
catalog zone $OLDCATZ to catalog zone $NEWCATZ, this appears in the
$OLDCATZ catalog zone as follows:
<unique-N>.zones.$OLDCATZ 0 IN PTR example.com.
coo.<unique-N>.zones.$OLDCATZ 0 IN PTR $NEWCATZ
The PTR RRset MUST consist of a single PTR record. The presence of
more than one record in the RRset indicates a broken catalog zone
which MUST NOT be processed (see Section 5.1).
When a consumer of a catalog zone $OLDCATZ receives an update which
adds or changes a coo property for a member zone in $OLDCATZ, it does
_not_ migrate the member zone immediately. The migration has to wait
for an update of $NEWCATZ. in which the member zone is present. The
consumer MUST verify, before the actual migration, that coo property
pointing to $NEWCATZ is still present in $OLDCATZ.
Unless the member node label (i.e., <unique-N>) for the member is the
same in $NEWCATZ, all its associated state for a just migrated zone
MUST be reset (see Section 5.6). Note that the owner of $OLDCATZ
allows for the zone associated state to be taken over by the owner of
$NEWCATZ by default. To prevent the takeover of state, the owner of
$OLDCATZ must remove this state by updating the associated properties
or by performing a zone state reset (see Section 5.6) before or
simultaneous with adding the coo property. (see also Section 7)
The old owner may remove the member zone containing the coo property
from $OLDCATZ once it has been established that all its consumers
have processed the Change of Ownership.
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4.3.2. Groups (group property)
With a group property, consumer(s) can be signaled to treat some
member zones within the catalog zone differently.
The consumer MAY apply different configuration options when
processing member zones, based on the value of the group property. A
group property value is stored as the entire RDATA of a TXT record
directly below the member node. The exact handling of the group
property value is left to the consumer's implementation and
configuration.
The producer MAY assign a group property to all, some, or none of the
member zones within a catalog zone. The producer MAY assign more
than one group property to one member zone. This will make it
possible to transfer group information for different consumer
operators in a single catalog zone. Implementations MAY facilitate
mapping of a specific group value to specific configuration
configurable _on a per catalog zone basis_ to allow for producers
that publish their catalog zone at multiple consumer operators.
Consumer operators SHOULD namespace their group values to reduce the
risk of having to resolve clashes.
The consumer MUST ignore group values it does not understand. When a
consumer encounters multiple group values for a single member zone,
it MAY choose to process all, some or none of them. This is left to
the implementation.
4.3.2.1. Example
Group properties are represented by TXT resource records. The record
content has no pre-defined meaning. Their interpretation is purely a
matter of agreement between the producer and the consumer(s) of the
catalog.
For example, the "foo" group could be agreed to indicate that a zone
not be signed with DNSSEC. Conversely, an agreement could define
that group names starting with "operator-" indicate in which way a
given DNS operator should set up certain aspects of the member zone's
DNSSEC configuration.
Assuming that the catalog producer and consumer(s) have established
such agreements, consider the following catalog zone (snippet) which
signals to consumer(s) how to treat DNSSEC for the zones
"example.net." and "example.com.":
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<unique-1>.zones.$CATZ 0 IN PTR example.com.
group.<unique-1>.zones.$CATZ 0 IN TXT "foo"
<unique-2>.zones.$CATZ 0 IN PTR example.net.
group.<unique-2>.zones.$CATZ 0 IN TXT "operator-x-foo"
group.<unique-2>.zones.$CATZ 0 IN TXT "operator-y" "bar"
In this scenario, consumer(s) shall, by agreement, not sign the
member zone "example.com." with DNSSEC. For "example.net.", the
consumers, at two different operators, will configure the member zone
to be signed with a specific combination of settings. The group
value that indicates that depends on what has been agreed with each
operator ("operator-x-foo" vs. "operator-y" "bar").
4.4. Custom Properties (*.ext properties)
Implementations and operators of catalog zones may choose to provide
their own properties. Custom properties can occur both globally, or
for a specific member zone. To prevent a name clash with future
properties, such properties MUST be represented below the label
"ext".
"ext" is not a placeholder. A custom property is named as follows:
; a global custom property:
<property-prefix>.ext.$CATZ
; a member zone custom property:
<property-prefix>.ext.<unique-N>.zones.$CATZ
<property-prefix> may consist of one or more labels.
Implementations SHOULD namespace their custom properties to limit
risk of clashes with other implementations of catalog zones. This
can be achieved by using two labels as the <property-prefix>, so that
the name of the implementation is included in the prefix: <some-
setting>.<implementation-name>.ext.$CATZ.
Implementations MAY use such properties on the member zone level to
store additional information about member zones, for example to flag
them for specific treatment.
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Further, implementations MAY use custom properties on the global
level to store additional information about the catalog zone itself.
While there may be many use cases for this, a plausible one is to
store default values for custom properties on the global level, then
overriding them using a property of the same name on the member level
(= under the ext label of the member node) if so desired. A property
agreement between producer and consumer should clearly define what
semantics apply, and whether a property is global, member, or both.
The meaning of the custom properties described in this section is
determined by the implementation alone, without expectation of
interoperability.
5. Nameserver Behavior
5.1. General Requirements
As it is a regular DNS zone, a catalog zone can be transferred using
DNS zone transfers among nameservers.
Catalog updates should be automatic, i.e., when a nameserver that
supports catalog zones completes a zone transfer for a catalog zone,
it SHOULD apply changes to the catalog within the running nameserver
automatically without any manual intervention.
Nameservers MAY allow loading and transfer of broken zones with
incorrect catalog zone syntax (as they are treated as regular zones).
The reason a catalog zone is considered broken SHOULD be communicated
clearly to the operator (e.g. through a log message).
When a previously correct catalog zone becomes a broken catalog zone,
because of an update through an incremental transfer or otherwise, it
loses its catalog meaning. No special processing occurs. Member
zones previously configured by this catalog MUST NOT be removed or
reconfigured in any way.
If a name server restarts with a broken catalog zone, the broken
catalog SHOULD NOT prevent the name server from starting up and
serving the member zones in the last valid version of the catalog
zone.
Processing of a broken catalog SHALL start (or resume) when the
catalog turns into a correct catalog zone, for example by an
additional update (through zone transfer or updates) fixing the
catalog zone.
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Similarly, when a catalog zone expires, it loses its catalog meaning
and MUST no longer be processed as such. No special processing
occurs until the zone becomes fresh again.
5.2. Member zone name clash
If there is a clash between an existing zone's name (either from an
existing member zone or otherwise configured zone) and an incoming
member zone's name (via transfer or update), the new instance of the
zone MUST be ignored and an error SHOULD be logged.
A clash between an existing member zone's name and an incoming member
zone's name (via transfer or update), may be an attempt to migrate a
zone to a different catalog, but should not be treated as one except
as described in Section 4.3.1.
5.3. Member zone removal
When a member zone is removed from a specific catalog zone, a
consumer MUST NOT remove the zone and associated state data if the
zone was not configured from that specific catalog zone. Only when
the zone was configured from a specific catalog zone, and the zone is
removed as a member from that specific catalog zone, the zone and
associated state (such as zone data and DNSSEC keys) MUST be removed
from the consumer. Consumer operators may consider to temporarily
archive associated state to facilitate mistake recovery.
5.4. Member node name change
When via a single update or transfer, the member node's label value
(<unique-N>) changes, catalog consumers MUST process this as a member
zone removal including all the zone's associated state (as described
in Section 5.3), immediately followed by processing the member as a
newly to be configured zone in the same catalog.
5.5. Migrating member zones between catalogs
If all consumers of the catalog zones involved support the coo
property, it is RECOMMENDED to perform migration of a member zone by
following the procedure described in Section 4.3.1. Otherwise, a
migration of a member zone from a catalog zone $OLDCATZ to a catalog
zone $NEWCATZ has to be done by: first removing the member zone from
$OLDCATZ; second adding the member zone to $NEWCATZ.
If in the process of a migration some consumers of the involved
catalog zones did not catch the removal of the member zone from
$OLDCATZ yet (because of a lost packet or downtime or otherwise), but
did already see the update of $NEWCATZ, they may consider the update
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adding the member zone in $NEWCATZ to be a name clash (see
Section 5.2) and as a consequence the member is not migrated to
$NEWCATZ. This possibility needs to be anticipated with a member
zone migration. Recovery from such a situation is out of the scope
of this document. It may for example entail a manually forced
retransfer of $NEWCATZ to consumers after they have been detected to
have received and processed the removal of the member zone from
$OLDCATZ.
5.6. Zone-associated state reset
It may be desirable to reset state (such as zone data and DNSSEC
keys) associated with a member zone.
A zone state reset may be performed by a change of the member node's
name (see Section 5.4).
6. Implementation and Operational Notes
Although any valid domain name can be used for the catalog name
$CATZ, a catalog producer MUST NOT use names that are not under the
control of the catalog producer (with the exception of reserved
names). It is RECOMMENDED to use either a domain name owned by the
catalog producer, or to use a name under a suitable name such as
"invalid." [RFC6761].
Catalog zones on secondary nameservers would have to be set up
manually, perhaps as static configuration, similar to how ordinary
DNS zones are configured when catalog zones or another automatic
configuration mechanism are not in place. The secondary additionally
needs to be configured as a catalog consumer for the catalog zone to
enable processing of the member zones in the catalog, such as
automatic synchronization of the member zones for secondary service.
Operators of catalog consumers should note that secondary name
servers may receive DNS NOTIFY messages [RFC1996] for zones before
they are seen as newly added member zones to the catalog from which
that secondary is provisioned.
Although they are regular DNS zones, catalog zones contain only
information for the management of a set of authoritative nameservers.
To prevent unintended exposure to other parties, operators SHOULD
limit the systems able to query these zones.
Querying/serving catalog zone contents may be inconvenient via DNS
due to the nature of their representation. An administrator may
therefore want to use a different method for looking at data inside
the catalog zone. Typical queries might include dumping the list of
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member zones, dumping a member zone's effective configuration,
querying a specific property value of a member zone, etc. Because of
the structure of catalog zones, it may not be possible to perform
these queries intuitively, or in some cases, at all, using DNS QUERY.
For example, it is not possible to enumerate the contents of a
multivalued property (such as the list of member zones) with a single
QUERY. Implementations are therefore advised to provide a tool that
uses either the output of AXFR or an out-of-band method to perform
queries on catalog zones.
Great power comes with great responsibility: Catalog zones simplify
zone provisioning by orchestrating zones on secondary name servers
from a single data source - the catalog. Hence, the catalog producer
has great power and changes must be treated carefully. For example
if the catalog is generated by some script and this script for
whatever reason generates an empty catalog, millions of member zones
may get deleted from their secondaries within seconds and all the
affected domains may be offline in a blink of an eye.
7. Security Considerations
As catalog zones are transmitted using DNS zone transfers, it is
RECOMMENDED that catalog zone transfers are protected from unexpected
modifications by way of authentication, for example by using TSIG
[RFC8945], or Strict or Mutual TLS authentication with DNS Zone
transfer over TLS or QUIC [RFC9103].
Use of DNS UPDATE [RFC2136] to modify the content of catalog zones
SHOULD similarly be authenticated.
Zone transfers of member zones SHOULD similarly be authenticated.
TSIG shared secrets used for member zones SHOULD NOT be mentioned in
the catalog zone data. However, key identifiers may be shared within
catalog zones.
Catalog zones reveal the zones served by their consumers, including
their properties. To prevent unintentional exposure of catalog zone
contents, it is RECOMMENDED to limit the systems able to query them
and to conduct catalog zone transfers confidentially [RFC9103].
As with regular zones, primary and secondary nameservers for a
catalog zone may be operated by different administrators. The
secondary nameservers may be configured as a catalog consumer to
synchronize catalog zones from the primary, but the primary's
administrators may not have any administrative access to the
secondaries.
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Administrative control over what zones are served from the configured
name servers shifts completely from the server operator (consumer) to
the "owner" (producer) of the catalog zone content. To prevent
unintended provisioning of zones, consumer(s) SHOULD scope the set of
admissible member zones by any means deemed suitable (such as
statically, via regular expressions, or dynamically, by verifying
against another database before accepting a member zone).
With migration of member zones between catalogs using the coo
property, it is possible for the owner of the target catalog (i.e.,
$NEWCATZ) to take over all its associated state with the zone from
the original owner (i.e., $OLDCATZ) by maintaining the same member
node label (i.e., <unique-N>). To prevent the takeover of the zone
associated state, the original owner has to enforce a zone state
reset by changing the member node label (see Section 5.6) before or
simultaneously with adding the coo property.
8. IANA Considerations
IANA is requested to create a registry on the "Domain Name System
(DNS) Parameters" IANA web page as follows:
Registry Name: DNS Catalog Zones Properties
Assignment Policy: Expert Review, except for property prefixes
ending in the label "ext", which are for Private Use.
Reference: [this document]
Note: This registry does not apply to Catalog Zones version "1", but
applies to Catalog Zones version "2" as specified in [this
document].
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+=================+======================+===========+===========+
| Property prefix | Description | Status | Reference |
+=================+======================+===========+===========+
| zones | List of member zones | Standards | [this |
| | | Track | document] |
+-----------------+----------------------+-----------+-----------+
| version | Schema version | Standards | [this |
| | | Track | document] |
+-----------------+----------------------+-----------+-----------+
| coo | Change of Ownership | Standards | [this |
| | | Track | document] |
+-----------------+----------------------+-----------+-----------+
| group | Group | Standards | [this |
| | | Track | document] |
+-----------------+----------------------+-----------+-----------+
| *.ext | Custom properties | Private | [this |
| | | Use | document] |
+-----------------+----------------------+-----------+-----------+
Table 1
The meanings of the fields are as follows:
Property prefix: One or more domain name labels
Description: A human readable short description or name for the
property
Status: IETF Document status or "External" if not documented in an
IETF document.
Reference: A stable reference to the document in which this property
is defined.
9. Acknowledgements
Our deepest thanks and appreciation go to Stephen Morris, Ray Bellis
and Witold Krecicki who initiated this draft and did the bulk of the
work.
Catalog zones originated as the chosen method among various proposals
that were evaluated at ISC for easy zone management. The chosen
method of storing the catalog as a regular DNS zone was proposed by
Stephen Morris.
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The initial authors discovered that Paul Vixie's earlier [Metazones]
proposal implemented a similar approach and reviewed it. Catalog
zones borrow some syntax ideas from Metazones, as both share this
scheme of representing the catalog as a regular DNS zone.
Thanks to Leo Vandewoestijne. Leo's presentation in the DNS devroom
at the FOSDEM'20 [FOSDEM20] was one of the motivations to take up and
continue the effort of standardizing catalog zones.
Thanks to Joe Abley, David Blacka, Brian Conry, Klaus Darilion, Brian
Dickson, Tony Finch, Evan Hunt, Shane Kerr, Warren Kumari, Patrik
Lundin, Matthijs Mekking, Victoria Risk, Josh Soref, Petr Spacek,
Michael StJohns, Carsten Strotmann and Tim Wicinski for reviewing
draft proposals and offering comments and suggestions.
10. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.
[RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
DOI 10.17487/RFC1982, August 1996,
<https://www.rfc-editor.org/info/rfc1982>.
[RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone
Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996,
August 1996, <https://www.rfc-editor.org/info/rfc1996>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, DOI 10.17487/RFC2136, April 1997,
<https://www.rfc-editor.org/info/rfc2136>.
[RFC2606] Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS
Names", BCP 32, RFC 2606, DOI 10.17487/RFC2606, June 1999,
<https://www.rfc-editor.org/info/rfc2606>.
[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
RFC 6761, DOI 10.17487/RFC6761, February 2013,
<https://www.rfc-editor.org/info/rfc6761>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/info/rfc8499>.
[RFC8945] Dupont, F., Morris, S., Vixie, P., Eastlake 3rd, D.,
Gudmundsson, O., and B. Wellington, "Secret Key
Transaction Authentication for DNS (TSIG)", STD 93,
RFC 8945, DOI 10.17487/RFC8945, November 2020,
<https://www.rfc-editor.org/info/rfc8945>.
[RFC9103] Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A.
Mankin, "DNS Zone Transfer over TLS", RFC 9103,
DOI 10.17487/RFC9103, August 2021,
<https://www.rfc-editor.org/info/rfc9103>.
11. Informative References
[FOSDEM20] Vandewoestijne, L., "Extending Catalog zones - another
approach in automating maintenance", 2020,
<https://archive.fosdem.org/2020/schedule/event/
dns_catz/>.
[Metazones]
Vixie, P., "Federated Domain Name Service Using DNS
Metazones", 2005,
<http://family.redbarn.org/~vixie/mz.pdf>.
Appendix A. Catalog Zone Example
The following is a full example of a catalog zone containing three
member zones with various properties:
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catalog.invalid. 0 SOA invalid. (
invalid. 1625079950 3600 600 2147483646 0 )
catalog.invalid. 0 NS invalid.
example.vendor.ext.catalog.invalid. 0 CNAME example.net.
version.catalog.invalid. 0 TXT "2"
nj2xg5b.zones.catalog.invalid. 0 PTR example.com.
nvxxezj.zones.catalog.invalid. 0 PTR example.net.
group.nvxxezj.zones.catalog.invalid. 0 TXT (
"operator-x-foo" )
nfwxa33.zones.catalog.invalid. 0 PTR example.org.
coo.nfwxa33.zones.catalog.invalid. 0 PTR (
newcatz.invalid. )
group.nfwxa33.zones.catalog.invalid. 0 TXT (
"operator-y-bar" )
metrics.vendor.ext.nfwxa33.zones.catalog.invalid. 0 CNAME (
collector.example.net. )
Appendix B. Implementation Status
*Note to the RFC Editor*: please remove this entire appendix before
publication.
In the following implementation status descriptions, "DNS Catalog
Zones" refers to DNS Catalog Zones version 2 as described in this
document. Version 1 of catalog zones was initially developed by ISC
for BIND, but never standardized in the IETF. Support for version 1
catalog zones is explicitly mentioned per implementation. Support
for the coo and group properties are also explicitly mentioned per
implementation.
* Knot DNS 3.1 (released August 2, 2021) supports both producing and
consuming of catalog zones, including the group property.
* PowerDNS from version 4.7 (released October 3, 2022) supports both
producing and consuming of catalog zones version 2 and consuming
of catalog zones version 1. PowerDNS does support the coo
property, and the group property on the producing side.
* Proof of concept python scripts (https://github.com/IETF-
Hackathon/NSDCatZ) that can be used for both generating and
consuming DNS Catalog Zones with NSD have been developed during
the hackathon at the IETF-109.
* BIND 9.18.3+ supports version 2 catalog zones as described in this
document including the coo property, as well as version 1 catalog
zones.
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Interoperability between the above implementations has been tested
during the hackathon at the IETF-109.
Appendix C. Change History
*Note to the RFC Editor*: please remove this entire appendix before
publication.
* draft-muks-dnsop-dns-catalog-zones-00
| Initial public draft.
* draft-muks-dnsop-dns-catalog-zones-01
| Added Witold, Ray as authors. Fixed typos, consistency issues.
| Fixed references. Updated Area. Removed newly introduced custom
| RR TYPEs. Changed schema version to 1. Changed TSIG requirement
| from MUST to SHOULD. Removed restrictive language about use of
| DNS QUERY. When zones are introduced into a catalog zone, a
| primary SHOULD first make the new zones available for transfers
| first (instead of MUST). Updated examples, esp. use IPv6 in
| examples per Fred Baker. Add catalog zone example.
* draft-muks-dnsop-dns-catalog-zones-02
| Addressed some review comments by Patrik Lundin.
* draft-muks-dnsop-dns-catalog-zones-03
| Revision bump.
* draft-muks-dnsop-dns-catalog-zones-04
| Reordering of sections into more logical order. Separation of
| multi-valued properties into their own category.
* draft-toorop-dnsop-dns-catalog-zones-00
| New authors to pickup the editor pen on this draft
|
| Remove data type definitions for zone properties Removing
| configuration of member zones through zone properties altogether
|
| Remove Open issues and discussion Appendix, which was about zone
| options (including primary/secondary relationships) only.
* draft-toorop-dnsop-dns-catalog-zones-01
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| Added a new section "The Serial Property", introducing a new
| mechanism which can help with disseminating zones from the primary
| to the secondary nameservers in a timely fashion more reliably.
|
| Three different ways to provide a "serial" property with a member
| zone are offered to or the workgroup for discussion.
|
| Added a new section "Implementation Status", listing production
| ready, upcoming and Proof of Concept implementations, and
| reporting on interoperability of the different implementations.
* draft-toorop-dnsop-dns-catalog-zones-02
| Adding the coo property for zone migration in a controlled fashion
|
| Adding the group property for reconfigure settings of member zones
| in an atomic update
|
| Adding the epoch property to reset zone associated state in a
| controlled fashion
* draft-toorop-dnsop-dns-catalog-zones-03
| Big cleanup!
|
| Introducing the terms catalog consumer and catalog producer
|
| Reorganized topics to create a more coherent whole
|
| Properties all have consistent format now
|
| Try to assume the least possible from implementations w.r.t.:
|
| 1) Predictability of the <unique-N> IDs of member zones
|
| 2) Whether or not fallback catalog zones can be found for a member
|
| 3) Whether or not a catalog consumer can maintain state
* draft-toorop-dnsop-dns-catalog-zones-04
| Move Implementation status to appendix
|
| Miscellaneous textual improvements
|
| coo property points to $NEWCATZ (and not zones.$NEWCATZ)
|
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| Remove suggestion to increase serial and remove member zone from
| $OLDCATZ after migration
|
| More consistent usage of the terms catalog consumer and catalog
| producer throughout the document
|
| Better (safer) description of resetting refresh timers of member
| zones with the serial property
|
| Removing a member MUST remove zone associated state
|
| Make authentication requirements a bit less prescriptive in
| security considerations
|
| Updated implementation status for KnotDNS
|
| Describe member node name changes and update "Zone associated
| state reset" to use that as the mechanism for it.
|
| Add Peter Thomassen as co-author
|
| Complete removal of the epoch property. We consider consumer
| optimizations with predictable member node labels (for example
| based on a hash) out of the scope of this document.
|
| Miscellaneous editorial improvements
* draft-toorop-dnsop-dns-catalog-zones-05
| Add Kees Monshouwer as co-author
|
| Removed the "serial" property
|
| Allow custom properties on the global level
* draft-toorop-dnsop-dns-catalog-zones-06
| Move administrative control explanation to Security Considerations
|
| Move comment on query methods to Implementation Notes
|
| Clarify what happens on expiry
|
| Clarify catalog consumer behavior when MUST condition is violated
|
| Better text on ordering of operations for Change of Ownership
|
| Suggest to namespace custom properties
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|
| Clarify how to handle property record with wrong type
|
| Cover the case of multiple different <unique-N>'s having the same
| value
|
| Recommendations for naming catalog zones
|
| Add and operational note about notifies for not yet existing zones
|
| Add text about name server restarts with broken zones
|
| Great power comes with great responsibility (Thanks Klaus!)
|
| Mention the new BIND implementation
|
| All invalid properties cause a broken catalog zone, including
| invalid group and version properties.
|
| Add Aram Sargsyan as author (he did the BIND9 implementation)
|
| group properties can have more than one value
* draft-toorop-dnsop-dns-catalog-zones-07
| Some spelling fixes from Tim Wicinski and Josh Soref
|
| Replace SHOULDs with MUSTs for ignoring things that are
| meaningless to a catalog consumer (Thanks Michael StJohns)
|
| Update the list of people to thank in the Acknowledgements section
|
| Mention PowerDNS support of catalog zones from version 4.7.0
| onwards
* draft-toorop-dnsop-dns-catalog-zones-08
| Address AD Review comments (editorial only)
|
| When DoT is mentioned, also mention now-standardized DoQ
* draft-toorop-dnsop-dns-catalog-zones-08
| Editorial nits from David Blacka, Lars Eggert, Russ Housley, Erik
| Kline, É (U+00C9)ric Vyncke and Paul Wouters
|
| Addes a Catalog Zone Exampla
|
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| Mention that the document uses DNS specific terminology and
| reference RFC8499
|
| Added IANA Considerations sections, with a registry for Catalog
| Zones properties
|
| Updated Implementation status also with respect to Catalog zones
| version "1" support
|
| Updates to Rename "group properties" to "group property values" or
| "group values" to reduce confusion about who will determine those
| values (operators and not implementations)
|
| Change example group values in non descriptive names
|
| Add some more clarifications on that and how group values are
| determined in producer/consumer agreements
|
| Stronger checking suggestion (SHOULD instead of MAY) in accepting
| member zones by consumers in the Security section
|
| Added mistake recovery text to the Member zone removal section
|
| Replace vague language ("meaningless") with more precise wording
|
| Catalog consumers that know only version "2" MUST not process
| version "1" catalog zones and consider it broken.
|
| The entire RDATA of a group property is it's value
Authors' Addresses
Peter van Dijk
PowerDNS
Den Haag
Netherlands
Email: peter.van.dijk@powerdns.com
Libor Peltan
CZ.NIC
Czechia
Email: libor.peltan@nic.cz
Ondrej Sury
Internet Systems Consortium
Czechia
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Email: ondrej@isc.org
Willem Toorop
NLnet Labs
Science Park 400
1098 XH Amsterdam
Netherlands
Email: willem@nlnetlabs.nl
Kees Monshouwer
Netherlands
Email: mind@monshouwer.eu
Peter Thomassen
deSEC, SSE - Secure Systems Engineering
Berlin
Germany
Email: peter@desec.io
Aram Sargsyan
Internet Systems Consortium
Email: aram@isc.org
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