DNS Catalog Zones
draft-ietf-dnsop-dns-catalog-zones-04
DNSOP Working Group P. van Dijk
Internet-Draft PowerDNS
Intended status: Standards Track L. Peltan
Expires: 28 April 2022 CZ.NIC
O. Sury
Internet Systems Consortium
W. Toorop
NLnet Labs
L. Vandewoestijne
P. Thomassen
deSEC, Secure Systems Engineering
25 October 2021
DNS Catalog Zones
draft-ietf-dnsop-dns-catalog-zones-04
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
van Dijk, et al. Expires 28 April 2022 [Page 1]
Internet-Draft dns-catalog-zones October 2021
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
and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Description . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Catalog Zone Structure . . . . . . . . . . . . . . . . . . . 4
4.1. SOA and NS Records . . . . . . . . . . . . . . . . . . . 4
4.2. Catalog Zone Schema Version . . . . . . . . . . . . . . . 5
4.3. List of Member Zones . . . . . . . . . . . . . . . . . . 5
5. Properties . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. The Change of Ownership (coo) Property . . . . . . . . . 6
5.2. The Group Property . . . . . . . . . . . . . . . . . . . 7
5.2.1. Group Property Example . . . . . . . . . . . . . . . 7
5.3. The Serial Property . . . . . . . . . . . . . . . . . . . 8
5.3.1. The SERIAL Resource Record . . . . . . . . . . . . . 9
5.3.2. SERIAL RDATA Wire Format . . . . . . . . . . . . . . 9
5.3.3. SERIAL Presentation Format . . . . . . . . . . . . . 9
5.3.4. SERIAL RR Usage . . . . . . . . . . . . . . . . . . . 9
5.4. Custom properties . . . . . . . . . . . . . . . . . . . . 10
6. Nameserver Behavior . . . . . . . . . . . . . . . . . . . . . 10
6.1. General Requirements . . . . . . . . . . . . . . . . . . 10
6.2. Member zone name clash . . . . . . . . . . . . . . . . . 11
6.3. Member zone removal . . . . . . . . . . . . . . . . . . . 11
6.4. Member node name change . . . . . . . . . . . . . . . . . 11
6.5. Migrating member zones between catalogs . . . . . . . . . 11
6.6. Zone associated state reset . . . . . . . . . . . . . . . 12
7. Implementation Notes . . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9.1. SERIAL RR type . . . . . . . . . . . . . . . . . . . . . 13
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11. Normative References . . . . . . . . . . . . . . . . . . . . 14
12. Informative References . . . . . . . . . . . . . . . . . . . 15
Appendix A. Implementation Status . . . . . . . . . . . . . . . 15
Appendix B. Change History (to be removed before final
publication) . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
van Dijk, et al. Expires 28 April 2022 [Page 2]
Internet-Draft dns-catalog-zones October 2021
1. Introduction
The content of a DNS zone is synchronized amongst 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 the
zone from all secondaries, either manually or via an external
application. This can be both inconvenient and error-prone; it is
also dependent on the nameserver implementation.
This document describes a method in which the catalog is represented
as a regular DNS zone (called a "catalog zone" here), and transferred
using DNS zone transfers. As zones are added to or removed from the
catalog zone, these changes are distributed to the secondary
nameservers in the normal way. The secondary nameservers 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 The 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 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
van Dijk, et al. Expires 28 April 2022 [Page 3]
Internet-Draft dns-catalog-zones October 2021
catalog zone (such as a DNS server that configures itself
according to the catalog zone's contents).
3. Description
A catalog zone is a DNS zone whose contents are specially crafted.
Its records 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 SHOULD ignore any RR in the catalog zone which is
meaningless or useless to the implementation.
Authoritative servers may be preconfigured 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 such zones.
A catalog zone is primarily intended for the management of a farm of
authoritative nameservers. The content of catalog zones may not be
accessible from any recursive nameserver.
4. Catalog Zone Structure
4.1. SOA and NS Records
As with any other DNS zone, a catalog zone MUST have a syntactically
correct SOA record and at least one NS record at its apex.
The SOA record's SERIAL, REFRESH, RETRY and EXPIRE fields [RFC1035]
are used during zone transfer. A catalog zone's SOA SERIAL field
MUST increase when an update is made to the catalog zone's contents
as per serial number arithmetic defined in [RFC1982]. Otherwise,
catalog consumers might not notice updates to the catalog zone's
contents.
There is no requirement to be able to query the catalog zone via
recursive nameservers. Catalog consumers MUST ignore and MUST NOT
assume or require NS records at the apex. However, at least one is
still required so that catalog zones are syntactically correct DNS
zones. A single NS RR with a NSDNAME field containing the absolute
name "invalid." is RECOMMENDED [RFC2606].
van Dijk, et al. Expires 28 April 2022 [Page 4]
Internet-Draft dns-catalog-zones October 2021
4.2. Catalog Zone Schema Version
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.$CATZ with at least one RR. Catalog
consumers MUST NOT apply catalog zone processing to zones without the
expected value in one of the RRs in the version.$CATZ TXT RRset, but
they may be transferred as ordinary zones. For this memo, the value
of one of the RRs in the version.CATZ TXT RRset MUST be set to "2",
i.e.
version.$CATZ 0 IN TXT "2"
NB: Version 1 was used in a draft version of this memo and reflected
the implementation first found in BIND 9.11.
4.3. List of Member Zones
The list of member zones is specified as a collection of member
nodes, represented by domain names under the owner name "zones" where
"zones" is a direct child domain of the catalog zone.
The names of member zones are represented on the RDATA side (instead
of as a part of owner names) of a PTR record, so that all valid
domain names may be represented regardless of their length [RFC1035].
This PTR record MUST be the only record in the PTR RRset with the
same name. More than one record in the RRset denotes a broken
catalog zone which MUST NOT be processed (see Section 6.1).
For example, if a catalog zone lists three zones "example.com.",
"example.net." and "example.org.", the member node RRs would appear
as follows:
<unique-1>.zones.$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 an unique value in the collection.
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 6.6).
Having the zones uniquely tagged with the <unique-N> label ensures
that additional RRs can be added below the member node (see
Section 5).
van Dijk, et al. Expires 28 April 2022 [Page 5]
Internet-Draft dns-catalog-zones October 2021
The CLASS field of every RR in a catalog zone MUST be IN (1).
The TTL field's value is not defined by this memo. Catalog zones are
for authoritative nameserver management only and are not intended for
general querying via recursive resolvers.
5. Properties
Each member zone MAY have one or more additional properties,
described in this chapter. These properties are completely optional
and catalog consumers SHOULD ignore those it does not understand.
Properties are represented by RRsets below the corresponding member
node.
5.1. The 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 in
the value of a PTR record 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. More than one
record in the RRset denotes a broken catalog zone which MUST NOT be
processed (see Section 6.1).
When a consumer of catalog zone $OLDCATZ receives an update which
adds or changes a coo property for a member zone in $OLDCATZ
signalling a new owner $NEWCATZ, it does _not_ migrate the member
zone immediately.
This is because the catalog consumer may not have the <unique-N>
identifier associated with the member zone in $NEWCATZ and because
name servers do not index Resource Records by RDATA, it may not know
wether or not the member zone is configured in $NEWCATZ at all. It
may have to wait for an update of $NEWCATZ adding or changing that
member zone. When a consumer of catalog zone $NEWCATZ receives an
update of $NEWCATZ which adds or changes a member zone, _and_ that
consumer had the member zone associated with $OLDCATZ, _and_ there is
a coo property of the member zone in $OLDCATZ pointing to $NEWCATZ,
_only then_ it will reconfigure the member zone with the for $NEWCATZ
preconfigured settings.
van Dijk, et al. Expires 28 April 2022 [Page 6]
Internet-Draft dns-catalog-zones October 2021
Unless the member node label (i.e. <unique-N>) for the member is the
same in $NEWCATZ, all associated state for a just migrated zone MUST
be reset (see Section 6.6). 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, the owner of $OLDCATZ
has to enforce a zone state reset by changing the member node label
(see Section 6.6) before or simultaneous with adding the coo
property. (see also Section 8)
The old owner may remove the member zone containing the coo property
from $OLDCATZ once it has been established that all its consumers
have processed the Change of Ownership.
5.2. The Group Property
With a group property, consumer(s) can be signalled to treat some
member zones within the catalog zone differently.
The consumer MAY apply different configuration options when
processing member zones, based on the value of the group property.
The exact handling of configuration referred to by the group property
value is left to the consumer's implementation and configuration.
The property is defined by a TXT record in the sub-node labelled
group.
The producer MAY assign a group property to all, some, or none of the
member zones within a catalog zone. The producer MUST NOT assign
more than one group property to one member zone.
The consumer MUST ignore either all or none of the group properties
in a catalog zone.
The value of the TXT record MUST be at most 255 octets long and MUST
NOT contain whitespace characters. The consumer MUST interpret the
value case-sensitively.
5.2.1. Group Property Example
<unique-1>.zones.$CATZ 0 IN PTR example.com.
group.<unique-1>.zones.$CATZ 0 IN TXT sign-with-nsec3
<unique-2>.zones.$CATZ 0 IN PTR example.net.
group.<unique-2>.zones.$CATZ 0 IN TXT nodnssec
In this case, the consumer might be implemented and configured in the
way that the member zones with "nodnssec" group assigned will not be
signed with DNSSEC, and the zones with "sign-with-nsec3" group
assigned will be signed with DNSSEC with NSEC3 chain.
van Dijk, et al. Expires 28 April 2022 [Page 7]
Internet-Draft dns-catalog-zones October 2021
By generating the catalog zone (snippet) above, the producer signals
how the consumer shall treat DNSSEC for the zones example.net. and
example.com., respectively.
5.3. The Serial Property
The serial property helps in increasing reliability of zone update
signaling and may help in reducing NOTIFY and SOA query traffic.
The current default mechanism for prompting notifications of zone
changes from a primary nameserver to the secondaries via DNS NOTIFY
[RFC1996], can be unreliable due to packet loss, or secondary
nameservers temporarily not being reachable. In such cases the
secondary might pick up the change only after the refresh timer runs
out, which might take long and be out of the control of the primary
nameserver operator. Low refresh values in the zones being served
can alleviate update delays, but burden both the primary and
secondary nameservers with more refresh queries, especially with
larger numbers of secondary nameservers serving large numbers of
zones. To mitigate this, updates of zones MAY be signalled via
catalog zones with the help of a serial property.
The serial number in the SOA record of the most recent version of a
member zone MAY be provided by a serial property. When a serial
property is present for a member zone, catalog consumers MAY assume
this number to be the current serial number in the SOA record of the
most recent version of the member zone.
Catalog consumers which are secondary for that member zone, MAY
compare the serial property with the SOA serial since the last time
the zone was fetched. When the serial property is larger, the
secondary MAY initiate a zone transfer immediately without doing a
SOA query first. The SOA query may be omitted, because the SOA
serial has been obtained reliably via the catalog zone already.
Secondary nameservers MAY be configured to postpone the next refresh
by the SOA refresh value of the member zone (counted since the
transfer of the catalog zone) when the value of the serial property
was found to be equal to the served zone, the same way as if it had
queried the primary SOA directly and found it equal. Note that for
this mechanism it is essential that the catalog producer is keeping
the serial property up to date with the SOA serial value of the
member zone at all times. The catalog may not be lagging behind.
Increased robustness in having the latest version of a zone may be a
reason to *not* configure a secondary nameserver with this mechanism.
van Dijk, et al. Expires 28 April 2022 [Page 8]
Internet-Draft dns-catalog-zones October 2021
Primary nameservers MAY be configured to omit sending DNS NOTIFY
messages to secondary nameservers which are known to process the
serial property of the member zones in the associated catalog.
However they MAY also combine signalling of zone changes with the
serial property of a member zone, as well as sending DNS NOTIFY
messages, to anticipate slow updates of the catalog zone (due to
packet loss or other reasons) and to cater for secondaries that are
not a catalog consumer processing the serial property.
All comparisons of serial numbers MUST use "Serial number
arithmetic", as defined in [RFC1982]
5.3.1. The SERIAL Resource Record
The serial property value is provided with a SERIAL Resource Record.
The Type value for the SERIAL RR is TBD. The SERIAL RR is class
independent. The RDATA of the resource record consist of a single
field: Serial.
5.3.2. SERIAL RDATA Wire Format
The SERIAL RDATA wire format is encoded as follows:
1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Serial |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5.3.2.1. The Serial Field
The Serial field is a 32-bit unsigned integer in network byte order.
It is the serial number of the member zone's SOA record ([RFC1035]
section 3.3.13).
5.3.3. SERIAL Presentation Format
The presentation format of the RDATA portion is as follows:
The Serial fields is represented as an unsigned decimal integer.
5.3.4. SERIAL RR Usage
The serial property of a member zone is provided by a SERIAL RRset
with a single SERIAL RR named serial.<unique-N>.zones.$CATZ.
van Dijk, et al. Expires 28 April 2022 [Page 9]
Internet-Draft dns-catalog-zones October 2021
For example, if a catalog zone lists three zones "example.com.",
"example.net." and "example.org.", and a serial property is provided
for each of them, the RRs would appear as follows:
<unique-1>.zones.$CATZ 0 IN PTR example.com.
serial.<unique-1>.zones.$CATZ 0 IN SERIAL 3
<unique-2>.zones.$CATZ 0 IN PTR example.net.
serial.<unique-2>.zones.$CATZ 0 IN SERIAL 1634730530
<unique-3>.zones.$CATZ 0 IN PTR example.org.
serial.<unique-3>.zones.$CATZ 0 IN SERIAL 2020112405
5.4. Custom properties
More properties may be defined in future documents. These future
properties will be represented by RRsets directly below the name of a
member node.
Implementations and operators of catalog zones may choose to provide
their own properties. To prevent a name clash with future
properties, private properties should be represented below the label
ext.<unique-N>.zones.$CATZ. ext is not a placeholder, so a custom
property would have the domain name <your-label>.ext.<unique-
N>.zones.$CATZ
6. Nameserver Behavior
6.1. General Requirements
As it is a regular DNS zone, a catalog zone can be transferred using
DNS zone transfers among nameservers.
Although they are regular DNS zones, catalog zones contain only
information for the management of a set of authoritative nameservers.
For this reason, operators may want to limit the systems able to
query these zones. It may be inconvenient to serve some contents of
catalog zones via DNS queries anyway due to the nature of their
representation. A separate method of querying entries inside the
catalog zone may be made available by nameserver implementations (see
Section 7).
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.
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 catalog consumer to
van Dijk, et al. Expires 28 April 2022 [Page 10]
Internet-Draft dns-catalog-zones October 2021
synchronize catalog zones from the primary, but the primary's
administrators may not have any administrative access to the
secondaries.
Nameservers MAY allow loading and transfer of broken zones with
incorrect catalog zone syntax (as they are treated as regular zones),
but catalog consumers MUST NOT process such broken zones as catalog
zones. For the purpose of catalog processing, the broken catalogs
MUST be ignored.
6.2. 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 {#cooproperty}.
6.3. Member zone removal
When a member zone is removed from a specific catalog zone, an
authoritative server 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.
6.4. 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 6.3), immediately followed by processing the member as a
newly to be configured zone in the same catalog.
6.5. 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 5.1. Otherwise a
migration of 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.
van Dijk, et al. Expires 28 April 2022 [Page 11]
Internet-Draft dns-catalog-zones October 2021
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 down time or otherwise),
but did already see the update of $NEWCATZ, they may consider the
update adding the member zone in $NEWCATZ to be a name clash (see
Section 6.2) 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.
6.6. 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 6.4).
7. Implementation Notes
Catalog zones on secondary nameservers would have to be setup
manually, perhaps as static configuration, similar to how ordinary
DNS zones are configured. 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
synchronized of the member zones for secondary service.
An administrator may want to look at data inside a catalog zone.
Typical queries might include dumping the list of 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 multi-valued
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.
van Dijk, et al. Expires 28 April 2022 [Page 12]
Internet-Draft dns-catalog-zones October 2021
8. Security Considerations
As catalog zones are transmitted using DNS zone transfers, it is
RECOMMENDED that catalog zone transfer 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 [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 the consumers of the catalog
zone. It is RECOMMENDED to limit the systems able to query these
zones. It is RECOMMENDED to transfer catalog zones confidentially
[RFC9103].
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.
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 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 6.6) before or
simultaneously with adding the coo property.
9. IANA Considerations
9.1. SERIAL RR type
This document defines a new DNS RR type, SERIAL, in the "Resource
Record (RR) TYPEs" subregistry of the "Domain Name System (DNS)
Parameters" registry:
van Dijk, et al. Expires 28 April 2022 [Page 13]
Internet-Draft dns-catalog-zones October 2021
+========+=======+===========================+===========+
| TYPE | Value | Meaning | Reference |
+========+=======+===========================+===========+
| SERIAL | TBD | Version number of the | [this |
| | | original copy of the zone | document] |
+--------+-------+---------------------------+-----------+
Table 1
10. 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.
The initial authors discovered that Paul Vixie's earlier [Metazones]
proposal implemented a similar approach and reviewed it. Catalog
zones borrows some syntax ideas from Metazones, as both share this
scheme of representing the catalog as a regular DNS zone.
Thanks to Brian Conry, Tony Finch, Evan Hunt, Patrik Lundin, Victoria
Risk, Carsten Strotmann, and Kees Monshouwer for reviewing draft
proposals and offering comments and suggestions.
Thanks to Klaus Darilion who came up with the idea for the serial
property during the hackathon at the IETF-109. Thanks also to Shane
Kerr, Petr Spacek, Brian Dickson for further brainstorming and
discussing the serial property and how it would work best with
catalog zones.
11. 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>.
van Dijk, et al. Expires 28 April 2022 [Page 14]
Internet-Draft dns-catalog-zones October 2021
[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>.
[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>.
[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>.
12. Informative References
[Metazones]
Vixie, P., "Federated Domain Name Service Using DNS
Metazones", 2005,
<http://family.redbarn.org/~vixie/mz.pdf>.
Appendix A. Implementation Status
*Note to the RFC Editor*: please remove this entire section before
publication.
In the following implementation status descriptions, "DNS Catalog
Zones" refers to DNS Catalog Zones as described in this document.
* Knot DNS 3.1 (released August 2, 2021) supports full producing and
consuming of catalog zones, including the group property.
van Dijk, et al. Expires 28 April 2022 [Page 15]
Internet-Draft dns-catalog-zones October 2021
* PowerDNS has a proof of concept external program called PowerCATZ
(https://github.com/PowerDNS/powercatz/), that can process DNS
Catalog Zones.
* 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.
Interoperability between the above implementations has been tested
during the hackathon at the IETF-109.
Appendix B. Change History (to be removed before final 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
van Dijk, et al. Expires 28 April 2022 [Page 16]
Internet-Draft dns-catalog-zones October 2021
|
| Remove Open issues and discussion Appendix, which was about zone
| options (including primary/secondary relationships) only.
* draft-toorop-dnsop-dns-catalog-zones-01
| 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
van Dijk, et al. Expires 28 April 2022 [Page 17]
Internet-Draft dns-catalog-zones October 2021
|
| Miscellaneous textual improvements
|
| coo property points to $NEWCATZ (and not zones.$NEWCATZ)
|
| 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
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
van Dijk, et al. Expires 28 April 2022 [Page 18]
Internet-Draft dns-catalog-zones October 2021
Ondrej Sury
Internet Systems Consortium
Czechia
Email: ondrej@isc.org
Willem Toorop
NLnet Labs
Science Park 400
1098 XH Amsterdam
Netherlands
Email: willem@nlnetlabs.nl
Leo Vandewoestijne
Netherlands
Email: leo@dns.company
Peter Thomassen
deSEC, Secure Systems Engineering
Berlin
Germany
Email: peter@desec.io
van Dijk, et al. Expires 28 April 2022 [Page 19]