Internet DRAFT - draft-pounsett-transferring-automated-dnssec-zones
draft-pounsett-transferring-automated-dnssec-zones
Network Working Group M. Pounsett
Internet-Draft Rightside Group, Ltd.
Updates: 6781 (if approved) September 13, 2017
Intended status: Informational
Expires: March 17, 2018
Change of Operator Procedures for Automatically Published DNSSEC Zones
draft-pounsett-transferring-automated-dnssec-zones-03
Abstract
Section 4.3.5.1 of [RFC6781] "DNSSEC Operational Practices, version
2" describes a procedure for transitioning a DNSSEC signed zone from
one (cooperative) operator to another. The procedure works well in
many situations, but makes the assumption that it is feasible for the
two operators to simultaneously publish slightly different versions
of the zone being transferred. In some cases, such as with TLD
registries, operational considerations require both operators to
publish identical versions of the zone for the duration of the
transition. This document describes a modified transition procedure
which can be used in these cases.
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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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 17, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Changing Between Cooperating DNS Operators . . . . . . . . . 3
3.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Procedure Overview . . . . . . . . . . . . . . . . . . . 3
3.3. Procedure Notation . . . . . . . . . . . . . . . . . . . 3
3.4. The Procedure . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Normative References . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Document Source . . . . . . . . . . . . . . . . . . 7
Appendix B. Changelist . . . . . . . . . . . . . . . . . . . . . 7
B.1. Version pounsett-03 . . . . . . . . . . . . . . . . . . . 7
B.2. Version pounsett-02 . . . . . . . . . . . . . . . . . . . 7
B.3. Version pounsett-01 . . . . . . . . . . . . . . . . . . . 7
B.4. Version pounsett-00 . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The process described in "DNSSEC Operational Practices, version 2"
([RFC6781]), section 4.3.5.1 for cooperating DNS operators to move a
DNSSEC signed zone cannot be followed in all cases. When operators
are moving a zone that is automatically published and/or changes
rapidly, such as with a TLD or any other zone published from a
registration database, it may not be feasible for the operators to
publish different versions of the same zone.
In these cases, it would be necessary for one or both operators to
have the capability to add, remove, or alter arbitrary records inline
along the zone transfer path (such as modifying the NSSet, and
stripping RRSIGs). It cannot be assumed that this capability exists,
since few (if any) common DNS implementations include these
functions, and many custom implementations exist whose feature sets
cannot be predicted.
As a result, it must be assumed that operators moving an
automatically generated or frequently updated zone must be able to
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publish an identical zone while transitioning it from one operator to
another.
2. Applicability
This document is intended for operators intending to transfer
operational responsibility for DNSSEC-signed zones, while publishing
consistent zone data on both sets of name servers throughout the
transition.
Other procedures exist for operators who are unable to consistently
replicate data between both sets of name servers (e.g. through zone
transfer) or who do not require this level of zone consistency during
the transfer.
3. Changing Between Cooperating DNS Operators
3.1. Assumptions
In this scenario, it is assumed that the operators will not exchange
any private key material, but are otherwise fully cooperative. It is
also assumed that the zone publishing process will be transferred
between operators independently of the DNS operations. The simplest
case is to transition the publishing process after the DNS operations
move has been completed, and is the order that is assumed in this
document, although the reverse order is possible. During the
transition, the losing operator will provide the zone contents to the
gaining operator by some automatic means (typically zone transfer).
The transition of the publishing process is out of scope of this
document.
3.2. Procedure Overview
The DNS operations transition uses a modified pre-publish KSK and ZSK
rollover, whereby the losing operator pre-publishes the public KSK
and ZSK of the gaining operator. Part way through the transition,
the losing operator stops signing the zone and begins providing an
unsecure zone to the gaining operator, who begins signing. Once that
is done, the gaining operator continues to post-publish the public
keys of the losing operator until the TTLs of the original RRSIGs
expire.
3.3. Procedure Notation
In the timeline below, the losing operator is operator A, and the
gaining operator is operator B. Records representing data generated
by each operator are appended with the operator letter. DNSKEY
records are appended with the keytype; DNSKEY_Z is a ZSK, and
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DNSKEY_K is a KSK. RRSIGs are appended with the DNSKEY type they
were generated from, as well as the operator who generated them;
RRSIGs include in parentheses the RRSET type that they sign. For
example, RRSIG_Z_A(SOA) is the RRSIG generated with DNSKEY_Z_A and
signs the SOA record.
3.4. The Procedure
The KSK and ZSK rollover from the losing to gaining operator keys
involves six stages as described in Figure 1 and Figure 2.
Initial
The initial version of the zone. This zone is published and
signed by the losing operator. During this stage the gaining
operator should begin serving the zone on its name servers.
Pre-Publish
Operator A begins pre-publishing DNSKEY_K_B and DNSKEY_Z_B. At
the same time, the NS set at the apex of the zone is changed to
NS_B to begin moving traffic to the gaining name servers. The
operators MUST wait at least the time it takes for the data to
propagate to all authoritative servers plus the TTL of the DNSKEY
set before the Signing Migration step can be begun.
Re-Delegation
The parent changes the prent NS set to be NS_B, to match the NS
set at the apex of the child zone. The parent also begins
publishing the DS record for the gaining operator. The operators
MUST wait at least the time it takes for the data to propagate to
all the parent servers plus the TTL of the DS set before the
Signing Migration step can be begun.
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----------------------------------------------------------------
| initial | pre-publish | re-delegation |
----------------------------------------------------------------
| Parent: | Parent: | Parent: |
| NS_A | NS_A | |
| | | NS_B |
| DS_A | DS_A | DS_A |
| | | DS_B |
----------------------------------------------------------------
| Child: | Child: | Child: |
| Published by A | Published by A | Published by A |
| Signed by A | Signed by A | Signed by A |
| SOA_A0 | SOA_A1 | SOA_A1 |
| RRSIG_Z_A(SOA) | RRSIG_Z_A(SOA) | RRSIG_Z_A(SOA) |
| | | |
| NS_A | | |
| | NS_B | NS_B |
| RRSIG_Z_A(NS) | RRSIG_Z_A(NS) | RRSIG_Z_A(NS) |
| | | |
| DNSKEY_Z_A | DNSKEY_Z_A | DNSKEY_Z_A |
| | DNSKEY_Z_B | DNSKEY_Z_B |
| DNSKEY_K_A | DNSKEY_K_A | DNSKEY_K_A |
| | DNSKEY_K_B | DNSKEY_K_B |
| RRSIG_K_A(DNSKEY) | RRSIG_K_A(DNSKEY) | RRSIG_K_A(DNSKEY) |
----------------------------------------------------------------
Figure 1: Rollover for Cooperating Operators, Steps 1-3
Signing Migration
Once the new (pre-published) DNSKEY records and DS_B are in the
caches of validating clients the operators can swap signing
duties; DNSKEY_K_B and DNSKEY_Z_B become the active signing keys.
When the gaining operator begins signing the zone, either they
MUST strip the RRSIGs of the losing operator, or the losing
operator MUST begin producing an unsigned zone. The operators
MUST wait at least the largest TTL of any RRSIG in the zone before
moving on to the Old DS Removal step.
Old DS Removal
The parent now removes the old DS_A from its zone. The operators
MUST wait at least the TTL of the DS set before moving on to the
Post Migration step.
Post Migration
After the old DS set has expired from caches the gaining operator
may remove the losing operator DNSKEYs from the zone. At this
time it is assumed that the gaining operator stops whatever
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process was transferring zone data from the losing operator, and
the gaining operator begins publishing the zone.
----------------------------------------------------------------
| signing migration | old DS removal | post migration |
----------------------------------------------------------------
| Parent: | Parent: | Parent: |
| | | |
| NS_B | NS_B | NS_B |
| DS_A | | |
| DS_B | DS_B | DS_B |
----------------------------------------------------------------
| Child: | Child: | Child: |
| Published by A | Published by A | Published by B |
| Signed by B | Signed by B | Signed by B |
| SOA_A2 | SOA_A2 | SOA_B0 |
| RRSIG_Z_B(SOA) | RRSIG_Z_B(SOA) | RRSIG_Z_B(SOA) |
| | | |
| | | |
| NS_B | NS_B | NS_B |
| RRSIG_Z_B(NS) | RRSIG_Z_B(NS) | RRSIG_Z_B(NS) |
| | | |
| DNSKEY_Z_A | DNSKEY_Z_A | |
| DNSKEY_Z_B | DNSKEY_Z_B | DNSKEY_Z_B |
| DNSKEY_K_A | DNSKEY_K_A | |
| DNSKEY_K_B | DNSKEY_K_B | DNSKEY_K_B |
| RRSIG_K_B(DNSKEY) | RRSIG_K_B(DNSKEY) | RRSIG_K_B(DNSKEY) |
----------------------------------------------------------------
Figure 2: Rollover for Cooperating Operators, Steps 4-6
4. Security Considerations
This document raises no new security considerations. Please see
Section 6 of [RFC6781].
5. IANA Considerations
This document has no actions for IANA.
6. Normative References
[RFC6781] Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC
Operational Practices, Version 2", RFC 6781,
DOI 10.17487/RFC6781, December 2012,
<https://www.rfc-editor.org/info/rfc6781>.
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Appendix A. Document Source
[RFC Editor: Please remove this section before publication.]
This document is maintained at Github at
<https://github.com/mpounsett/operator-transfer>. Issue reports and
pull requests are gratefully accepted here.
The XML and TXT versions of this document are generated from Markdown
using mmark by Miek Gieben. mmark is available at
<https://github.com/miekg/mmark>.
Appendix B. Changelist
[RFC Editor: Please remove this section before publication.]
B.1. Version pounsett-03
o grammar and spelling nits
o fix RRSIG/DNSKEY typo in "Signing Migration" step
B.2. Version pounsett-02
o grammar and spelling nits
o separate procedural section into subsections
o improve notation explanation
o rename procedure steps for clarity
o add prose description of operator key roll
B.3. Version pounsett-01
o grammar and spelling nits
o added Security Considerations section
o added IANA Considerations section
o added Document Source and Changelist
o call out publishing migration as out of scope
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B.4. Version pounsett-00
Initial Submission
Author's Address
Matthew Pounsett
Rightside Group, Ltd.
Toronto, ON
Canada
Email: matt@conundrum.com
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