DNS Zone Transfer-over-TLS
draft-hzpa-dprive-xfr-over-tls-02

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dprive                                                          H. Zhang
Internet-Draft                                                   P. Aras
Updates: 1995 (if approved)                                   Salesforce
Intended status: Standards Track                               W. Toorop
Expires: January 9, 2020                                      NLnet Labs
                                                            S. Dickinson
                                                              Sinodun IT
                                                               A. Mankin
                                                              Salesforce
                                                            July 8, 2019

                       DNS Zone Transfer-over-TLS
                   draft-hzpa-dprive-xfr-over-tls-02

Abstract

   DNS zone transfers are transmitted in clear text, which gives
   attackers the opportunity to collect the content of a zone by
   eavesdropping on network connections.  The DNS Transaction Signature
   (TSIG) mechanism is specified to restrict direct zone transfer to
   authorized clients only, but it does not add confidentiality.  This
   document specifies use of DNS-over-TLS to prevent zone contents
   collection via passive monitoring of zone transfers.

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
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   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.

Zhang, et al.            Expires January 9, 2020                [Page 1]
Internet-Draft                XFR-over-TLS                     July 2019

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Use Cases for XFR-over-TLS  . . . . . . . . . . . . . . . . .   4
   4.  Connection and Data Flows in Existing XFR Mechanisms  . . . .   5
     4.1.  AXFR Mechanism  . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  IXFR Mechanism  . . . . . . . . . . . . . . . . . . . . .   6
     4.3.  Data Leakage of NOTIFY and SOA Message Exchanges  . . . .   7
       4.3.1.  NOTIFY  . . . . . . . . . . . . . . . . . . . . . . .   7
       4.3.2.  SOA . . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Connection and Data Flows in XoT  . . . . . . . . . . . . . .   8
     5.1.  Performance Considerations  . . . . . . . . . . . . . . .   8
     5.2.  AXoT mechanism  . . . . . . . . . . . . . . . . . . . . .   8
     5.3.  IXoT mechanism  . . . . . . . . . . . . . . . . . . . . .   9
       5.3.1.  Fallback to AXFR  . . . . . . . . . . . . . . . . . .  10
   6.  Zone Transfer with DoT - Authentication . . . . . . . . . . .  10
     6.1.  TSIG  . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     6.2.  TLS . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
       6.2.1.  Opportunistic . . . . . . . . . . . . . . . . . . . .  10
       6.2.2.  Strict  . . . . . . . . . . . . . . . . . . . . . . .  10
       6.2.3.  Mutual  . . . . . . . . . . . . . . . . . . . . . . .  10
     6.3.  IP Based ACL on the Primary . . . . . . . . . . . . . . .  11
     6.4.  ZONEMD  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     6.5.  Comparison of Authentication Methods  . . . . . . . . . .  11
   7.  Policies for Both AXFR and IXFR . . . . . . . . . . . . . . .  12
   8.  Multi-primary Configurations  . . . . . . . . . . . . . . . .  13
   9.  Implementation Considerations . . . . . . . . . . . . . . . .  13
   10. Implementation Status . . . . . . . . . . . . . . . . . . . .  14
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  14