Internet DRAFT - draft-dsawp-notify
draft-dsawp-notify
Network Working Group J. Levine
Internet-Draft Standcore LLC
Updates: 1996 (if approved) 29 May 2023
Intended status: Standards Track
Expires: 30 November 2023
NOTIFY for DNSSEC updates
draft-dsawp-notify-00
Abstract
This document specifes a new usage of DNS NOTIFY to install and
update DNSSEC key information.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 30 November 2023.
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Copyright (c) 2023 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. NOTIFY usage for key updates . . . . . . . . . . . . . . . . 2
3. Identifying the parent to notify . . . . . . . . . . . . . . 3
4. Security considerations . . . . . . . . . . . . . . . . . . . 3
5. Normative References . . . . . . . . . . . . . . . . . . . . 3
6. Informative References . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
[RFC1996] defines the NOTIFY opcode for DNS and its use to alert
secondary name servers that the contents of a zone has changed.
[RFC7344] specifies the method to pass DNSSEC key changes from child
to parent zones using CDS and CDNSKEY records. [RFC8078] describes a
method to pass initial DNSSEC key records from child to parent using
CDS and CDNSKEY records, while [I-D.ietf-dnsop-dnssec-bootstrapping]
describes a more secure alternative.
All three of these methods currently depend on a parent zone
periodically scanning child zones to check for updates, which limits
the speed of DNSSEC updates and potentially puts a large load on
parent zones with many child zones. A new usage of DNS NOTIFY allows
a child zone to tell the parent zone that DNSSEC key information has
changed, so the parent can promptly scan the child zone and perform
updates.
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.
2. NOTIFY usage for key updates
In Section 2 of [RFC1996], the server sending the NOTIFY queries is
called the Master and the one receiving and answering them is called
the Slave. In this application, a server for a child zone sends the
queries, and a server for the parent zone receives and answers them.
The format of a NOTIFY query and answer is unchanged from that in
Section 3 of [RFC1996]. The QTYPE of the request MUST be CDS or
CDNSKEY, to indicate that CDS or CDNSKEY records in the child zone
have been added or updated. The answer section SHOULD contain copies
of the new CDS or CDNSKEY records, which the parent can use to
disregard duplicate requests, as in Section 3.7 of [RFC1996].
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When the parent receives a non-duplicate request, if it already has
DNSSEC key records for the child zone, it scans for updates as in
[RFC7344]. If it does not, it uses the process from [RFC8078] or
[I-D.ietf-dnsop-dnssec-bootstrapping] to possibly install new key
records.
A parent MUST ignore DNSSEC NOTIFY messages that are not for zones
that are immediate children of the parent, other than optionally
logging an error message.
In some cases a zone may have multiple signers. The multiple signers
have to coordinate CDS and CDNSKEY updates as described in Section 8
of [RFC8901] and it is up to them to coordinate which of them sends
NOTIFY queries, or whether they both can do so.
3. Identifying the parent to notify
In some cases, NOTIFY messages are sent to one of the DNS servers for
the parent zone, but in other cases they may be sent to a different
host that manages the parent zone, analogous to Stealth servers in
Section 2.1 of [RFC1996].
This specification does not describe how to select or find the
correct target of the NOTIFY.
4. Security considerations
The NOTIFY messages are only a hint to do a scan that the parent
would eventually have done anyway, so they introduce no new DNSSEC
security issues.
Large numbers of NOTIFY messages could cause a denial of service
attack, just like any other unwanted traffic. Child servers MUST
limit the number of NOTIFY queries they send and parents MUST limit
the number of answers they send to avoid direct or reflection DoS
attacks.
5. Normative References
[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>.
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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>.
6. Informative References
[I-D.ietf-dnsop-dnssec-bootstrapping]
Thomassen, P. and N. Wisiol, "Automatic DNSSEC
Bootstrapping using Authenticated Signals from the Zone's
Operator", Work in Progress, Internet-Draft, draft-ietf-
dnsop-dnssec-bootstrapping-04, 1 May 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-
dnssec-bootstrapping-04>.
[RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating
DNSSEC Delegation Trust Maintenance", RFC 7344,
DOI 10.17487/RFC7344, September 2014,
<https://www.rfc-editor.org/info/rfc7344>.
[RFC8078] Gudmundsson, O. and P. Wouters, "Managing DS Records from
the Parent via CDS/CDNSKEY", RFC 8078,
DOI 10.17487/RFC8078, March 2017,
<https://www.rfc-editor.org/info/rfc8078>.
[RFC8901] Huque, S., Aras, P., Dickinson, J., Vcelak, J., and D.
Blacka, "Multi-Signer DNSSEC Models", RFC 8901,
DOI 10.17487/RFC8901, September 2020,
<https://www.rfc-editor.org/info/rfc8901>.
Author's Address
John Levine
Standcore LLC
Email: standards@standcore.com
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