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

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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 . . . . . . . . . . . . . . . . . .