DNS Zone Transfer-over-TLS
draft-ietf-dprive-xfr-over-tls-04

Document Type Active Internet-Draft (dprive WG)
Authors Willem Toorop  , Sara Dickinson  , Shivan Sahib  , Pallavi Aras  , Allison Mankin 
Last updated 2020-11-23
Replaces draft-hzpa-dprive-xfr-over-tls
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Intended RFC status Proposed Standard
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dprive                                                         W. Toorop
Internet-Draft                                                NLnet Labs
Updates: 1995, 5936, 7766 (if approved)                     S. Dickinson
Intended status: Standards Track                              Sinodun IT
Expires: May 27, 2021                                           S. Sahib
                                                                 P. Aras
                                                               A. Mankin
                                                              Salesforce
                                                       November 23, 2020

                       DNS Zone Transfer-over-TLS
                   draft-ietf-dprive-xfr-over-tls-04

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 TLS, rather then clear text, to prevent
   zone content collection via passive monitoring of zone transfers:
   XFR-over-TLS (XoT).  Additionally, this specification updates
   RFC1995, RFC5936 and RFC7766.

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 May 27, 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Toorop, et al.            Expires May 27, 2021                  [Page 1]
Internet-Draft                XFR-over-TLS                 November 2020

   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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Document work via GitHub  . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Use Cases for XFR-over-TLS  . . . . . . . . . . . . . . . . .   6
     4.1.  Threat model  . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Connection and Data Flows in Existing XFR Mechanisms  . . . .   7
     5.1.  AXFR Mechanism  . . . . . . . . . . . . . . . . . . . . .   7
     5.2.  IXFR Mechanism  . . . . . . . . . . . . . . . . . . . . .   9
     5.3.  Data Leakage of NOTIFY and SOA Message Exchanges  . . . .  11
       5.3.1.  NOTIFY  . . . . . . . . . . . . . . . . . . . . . . .  11
       5.3.2.  SOA . . . . . . . . . . . . . . . . . . . . . . . . .  11
   6.  Updates to existing specifications  . . . . . . . . . . . . .  11
     6.1.  Update to RFC1995 for IXFR-over-TCP . . . . . . . . . . .  12
     6.2.  Update to RFC5936 for AXFR-over-TCP . . . . . . . . . . .  13
     6.3.  Updates to RFC1995 and RFC5936 for XFR-over-TCP . . . . .  13
       6.3.1.  Connection reuse  . . . . . . . . . . . . . . . . . .  13
       6.3.2.  AXFRs and IXFRs on the same connection  . . . . . . .  13
       6.3.3.  XFR limits  . . . . . . . . . . . . . . . . . . . . .  14
       6.3.4.  The edns-tcp-keepalive EDNS0 Option . . . . . . . . .  14
       6.3.5.  Backwards compatibility . . . . . . . . . . . . . . .  15
     6.4.  Update to RFC7766 . . . . . . . . . . . . . . . . . . . .  15
   7.  XoT specification . . . . . . . . . . . . . . . . . . . . . .  16
     7.1.  TLS versions  . . . . . . . . . . . . . . . . . . . . . .  16
     7.2.  Port selection  . . . . . . . . . . . . . . . . . . . . .  16
     7.3.  High level XoT descriptions . . . . . . . . . . . . . . .  16
     7.4.  XoT transfers . . . . . . . . . . . . . . . . . . . . . .  18
     7.5.  XoT connections . . . . . . . . . . . . . . . . . . . . .  19
     7.6.  XoT vs ADoT . . . . . . . . . . . . . . . . . . . . . . .  19
     7.7.  Response RCODES . . . . . . . . . . . . . . . . . . . . .  20
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