Moving DNSSEC Lookaside Validation (DLV) to Historic Status
RFC 8749
Internet Engineering Task Force (IETF) W. Mekking
Request for Comments: 8749 D. Mahoney
Updates: 6698, 6840 ISC
Category: Standards Track March 2020
ISSN: 2070-1721
Moving DNSSEC Lookaside Validation (DLV) to Historic Status
Abstract
This document retires DNSSEC Lookaside Validation (DLV) and
reclassifies RFCs 4431 and 5074 as Historic. Furthermore, this
document updates RFC 6698 by excluding the DLV resource record from
certificates and updates RFC 6840 by excluding the DLV registries
from the trust anchor selection.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8749.
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Table of Contents
1. Introduction
2. Requirements Language
3. Discussion
4. Moving DLV to Historic Status
4.1. Documents That Reference the DLV RFCs
4.1.1. Documents That Reference RFC 4431
4.1.2. Documents That Reference RFC 5074
5. IANA Considerations
6. Security Considerations
7. Normative References
Acknowledgements
Authors' Addresses
1. Introduction
DNSSEC Lookaside Validation (DLV) was introduced to assist with the
adoption of DNSSEC [RFC4033] [RFC4034] [RFC4035] in a time when the
root zone and many top-level domains (TLDs) were unsigned. DLV
allowed entities with signed zones under an unsigned parent zone or
entities with registrars that did not accept DS records to publish
trust anchors outside of the normal DNS delegation chain. The root
zone was signed in July 2010, and as of May 2019, 1389 out of 1531
TLDs have a secure delegation from the root; thus, DLV has served its
purpose and can now retire.
2. Requirements Language
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.
3. Discussion
One could argue that DLV is still useful because there are still some
unsigned TLDs and entities under those zones that will not benefit
from signing their zone. However, keeping the DLV mechanism also has
disadvantages:
* It reduces the pressure to get the parent zone signed.
* It reduces the pressure on registrars to accept DS records.
* It complicates validation code.
In addition, not every validator actually implemented DLV (only BIND
9 and Unbound), so even if an entity can use DLV to set up an
alternate path to its trust anchor, its effect is limited.
Furthermore, there was one well-known DLV registry (dlv.isc.org),
which was deprecated (replaced with a signed empty zone) on September
30, 2017. With the absence of a well-known DLV registry service, it
is unlikely that there is a real benefit for the protocol on the
Internet nowadays.
One other possible reason to keep DLV is to distribute trust anchors
for private enterprises. There are no known uses of DLV for this.
All things considered, it is probably not worth the effort of
maintaining the DLV mechanism.
4. Moving DLV to Historic Status
There are two RFCs that specify DLV:
1. RFC 4431 [RFC4431] specifies the DLV resource record.
2. RFC 5074 [RFC5074] specifies the DLV mechanism for publishing
trust anchors outside the DNS delegation chain and how validators
can use them to validate DNSSEC-signed data.
This document moves both RFC 4431 [RFC4431] and RFC 5074 [RFC5074] to
Historic status. This is a clear signal to implementers that the DLV
resource record and the DLV mechanism SHOULD NOT be implemented or
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