Recursive to Authoritative DNS with Opportunistic Encryption
draft-pp-recursive-authoritative-opportunistic-04

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Network Working Group                                         P. Hoffman
Internet-Draft                                                     ICANN
Intended status: Standards Track                         13 January 2021
Expires: 17 July 2021

      Recursive to Authoritative DNS with Opportunistic Encryption
             draft-pp-recursive-authoritative-opportunistic-04

Abstract

   This document describes a use case and a method for a DNS recursive
   resolver to use opportunistic encryption (that is, encryption with
   optional authentication) when communicating with authoritative
   servers.  The motivating use case for this method is that more
   encryption on the Internet is better, and opportunistic encryption is
   better than no encryption at all.  The method here is optional for
   both the recursive resolver and the authoritative server.  Nothing in
   this method prevents use cases and methods that can use, or require,
   authenticated encryption.

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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   This Internet-Draft will expire on 17 July 2021.

Copyright Notice

   Copyright (c) 2021 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
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   Please review these documents carefully, as they describe your rights
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Hoffman                   Expires 17 July 2021                  [Page 1]
Internet-Draft  Opportunistic Recursive to Authoritative    January 2021

   extracted from this document must include Simplified BSD License text
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Use Case  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Summary of Protocol . . . . . . . . . . . . . . . . . . .   3
     1.3.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Method for Opportunistic Encryption . . . . . . . . . . . . .   4
     2.1.  Resolvers . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Authoritative Servers . . . . . . . . . . . . . . . . . .   5
   3.  Discovering Whether an Authoritative Server Uses
           Encryption  . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  The Transport Cache . . . . . . . . . . . . . . . . . . . . .   6
   5.  Authentication  . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   A recursive resolver using traditional DNS over port 53 may wish
   instead to use encrypted communication with authoritative servers in
   order to prevent passive snooping of its DNS traffic.  The recursive
   resolver can use opportunistic encryption (defined in [RFC7435] to
   achieve this goal.

   This document describes a use case and a method for recursive
   resolvers to use opportunistic encryption.  The use case is described
   in Section 1.1.  The method uses DNS-over-TLS [RFC7858] (DoT) with
   authoritative servers in an efficient manner; it is called "ADoT", as
   described in [I-D.ietf-dnsop-rfc8499bis]. (( A later version of this
   document will probably also describe the use of DNS-over-QUIC
   [I-D.ietf-dprive-dnsoquic] (DoQ). ))

   Because opportunistic encryption means encryption with optional
   authentication, a resolver using the mechanism described here could
   achieve authenticated encryption with some authoritative servers,
   depending on how authentication for ADoT is defined.  To date, there
   have been no definition of how a resolver can take advantage of DNS
   features that require authentication of authoritative servers.  If
   those advantages are defined in the future, this document would need