Aggressive Use of DNSSEC-Validated Cache
RFC 8198

Document Type RFC - Proposed Standard (July 2017; No errata)
Updates RFC 4035
Last updated 2017-07-25
Replaces draft-fujiwara-dnsop-nsec-aggressiveuse
Stream IETF
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Reviews GENART will not review this version
Stream WG state Submitted to IESG for Publication
Document shepherd Tim Wicinski
Shepherd write-up Show (last changed 2017-05-09)
IESG IESG state RFC 8198 (Proposed Standard)
Consensus Boilerplate Yes
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Responsible AD Terry Manderson
Send notices to "Tim Wicinski" <tjw.ietf@gmail.com>
IANA IANA review state IANA OK - No Actions Needed
IANA action state No IC
Internet Engineering Task Force (IETF)                       K. Fujiwara
Request for Comments: 8198                                          JPRS
Updates: 4035                                                    A. Kato
Category: Standards Track                                      Keio/WIDE
ISSN: 2070-1721                                                W. Kumari
                                                                  Google
                                                               July 2017

                Aggressive Use of DNSSEC-Validated Cache

Abstract

   The DNS relies upon caching to scale; however, the cache lookup
   generally requires an exact match.  This document specifies the use
   of NSEC/NSEC3 resource records to allow DNSSEC-validating resolvers
   to generate negative answers within a range and positive answers from
   wildcards.  This increases performance, decreases latency, decreases
   resource utilization on both authoritative and recursive servers, and
   increases privacy.  Also, it may help increase resilience to certain
   DoS attacks in some circumstances.

   This document updates RFC 4035 by allowing validating resolvers to
   generate negative answers based upon NSEC/NSEC3 records and positive
   answers in the presence of wildcards.

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
   http://www.rfc-editor.org/info/rfc8198.

Fujiwara, et al.             Standards Track                    [Page 1]
RFC 8198                    NSEC/NSEC3 Usage                   July 2017

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
   (http://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.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Aggressive Use of DNSSEC-Validated Cache  . . . . . . . . . .   6
     5.1.  NSEC  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  NSEC3 . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Wildcards . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.4.  Consideration on TTL  . . . . . . . . . . . . . . . . . .   7
   6.  Benefits  . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   7.  Update to RFC 4035  . . . . . . . . . . . . . . . . . . . . .   8
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     10.2.  Informative References . . . . . . . . . . . . . . . . .  10
   Appendix A.  Detailed Implementation Notes  . . . . . . . . . . .  11
   Appendix B.  Procedure for Determining ENT vs. NXDOMAIN with NSEC  11
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

Fujiwara, et al.             Standards Track                    [Page 2]
RFC 8198                    NSEC/NSEC3 Usage                   July 2017

1.  Introduction

   A DNS negative cache exists, and is used to cache the fact that an
   RRset does not exist.  This method of negative caching requires exact
   matching; this leads to unnecessary additional lookups, increases
   latency, leads to extra resource utilization on both authoritative
   and recursive servers, and decreases privacy by leaking queries.

   This document updates RFC 4035 to allow resolvers to use NSEC/NSEC3
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