Authoritative DNS-over-TLS Operational Considerations
draft-hal-adot-operational-considerations-00

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dprive or dnsop                                             K. Henderson
Internet-Draft                                                  Verisign
Intended status: Informational                                  T. April
Expires: January 9, 2020                                          Akamai
                                                            J. Livingood
                                                                 Comcast
                                                            July 8, 2019

         Authoritative DNS-over-TLS Operational Considerations
               draft-hal-adot-operational-considerations-00

Abstract

   DNS over TLS (DoT) has been gaining attention, primarily as a means
   of communication between stub resolvers and recursive resolvers.
   There have also been discussions and experiments involving the use of
   DoT to communicate with authoritative nameservers (Authoritative DNS
   over TLS or "ADoT"), including communication between recursive and
   authoritative resolvers.  However, we have identified a number of
   operational concerns with ADoT.  These operational concerns need to
   be addressed prior to ADoT's deployment at scale by DNS operators in
   order to maintain the stability and resilience of the global DNS.
   The document also provides some suggested next steps to advance the
   operator community's understanding of ADoT's operational impact.

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 January 9, 2020.

Copyright Notice

   Copyright (c) 2019 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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  Background and Motivation
       1.1.1.  Why operational considerations are so important for
               ADoT
       1.1.2.  Other considerations related to ADoT
   2.  Terminology
     2.1.  Requirements Language
     2.2.  Definitions
   3.  Key Issues and Questions
     3.1.  Signaling Support for ADoT
     3.2.  Port number
     3.3.  TLS version
     3.4.  Resumptions
     3.5.  Operational Monitoring
     3.6.  Architecture
     3.7.  Socket efficiency/tuning considerations
     3.8.  Post-Quantum Security
   4.  Suggestions for further research and development
     4.1.  Required studies and analysis
     4.2.  Authoritative DNS over TLS (ADoT) Profile
   5.  Security Considerations
   6.  References
     6.1.  Informative References
     6.2.  URIs
   Appendix A.  Acknowledgements
   Appendix B.  Change Log
   Authors' Addresses

1.  Introduction

   Typically, DNS communication between stub resolvers, recursive
   resolvers, and authoritative servers is not encrypted.  Some argue
   that this can pose a privacy challenge for Internet users, because
   their access to named network resources can potentially be tracked
   through their DNS communication.  In principle, any network element
   along the path between the user and resolving or authoritative
   nameservers could observe this unencrypted traffic.  Many of these
   concerns are addressed in [RFC7626].

   [RFC8310] proposes using DNS over TLS (DoT) in order to encrypt DNS
   traffic.

   Historically, much of the work on DNS encryption has focused on the
   stub-to-recursive path as the recursive-to-authoritative server path
   does not leak user specific information.  However, with the increased
   deployment of EDNS0 Client Subnet [RFC7871], recursive-to-
   authoritative encryption is becoming an area of interest.  Therefore,
   this document focuses on the recursive-to-authoritative aspect of DoT
   and we use the term Authoritative DNS over TLS (ADoT) in order to
   differentiate it from the stub-to-recursive path.

   The addition of ADoT, while providing encryption for DNS
   communication, also introduces other factors that might impact the