DNS Transport over TCP - Operational Requirements
draft-ietf-dnsop-dns-tcp-requirements-05

Document Type Active Internet-Draft (dnsop WG)
Last updated 2019-11-02
Replaces draft-kristoff-dnsop-dns-tcp-requirements
Stream IETF
Intended RFC status Best Current Practice
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Domain Name System Operations                                J. Kristoff
Internet-Draft                                         DePaul University
Updates: 1123 (if approved)                                   D. Wessels
Intended status: Best Current Practice                          Verisign
Expires: May 4, 2020                                    November 1, 2019

           DNS Transport over TCP - Operational Requirements
                draft-ietf-dnsop-dns-tcp-requirements-05

Abstract

   This document encourages the practice of permitting DNS messages to
   be carried over TCP on the Internet.  This includes both DNS over
   unencrypted TCP, as well as over an encrypted TLS session.  The
   document also considers the consequences with this form of DNS
   communication and the potential operational issues that can arise
   when this best common practice is not upheld.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 4, 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
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of

Kristoff & Wessels         Expires May 4, 2020                  [Page 1]
Internet-Draft           DNS Transport over TCP            November 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Uneven Transport Usage and Preference . . . . . . . . . .   4
     2.2.  Waiting for Large Messages and Reliability  . . . . . . .   5
     2.3.  EDNS0 . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.4.  Fragmentation and Truncation  . . . . . . . . . . . . . .   6
     2.5.  "Only Zone Transfers Use TCP" . . . . . . . . . . . . . .   7
   3.  DNS over TCP Requirements . . . . . . . . . . . . . . . . . .   7
   4.  Network and System Considerations . . . . . . . . . . . . . .   8
     4.1.  Connection Admission  . . . . . . . . . . . . . . . . . .   8
     4.2.  Connection Management . . . . . . . . . . . . . . . . . .   9
     4.3.  Connection Termination  . . . . . . . . . . . . . . . . .  10
   5.  DNS over TCP Filtering Risks  . . . . . . . . . . . . . . . .  11
     5.1.  DNS Wedgie  . . . . . . . . . . . . . . . . . . . . . . .  11
     5.2.  DNS Root Zone KSK Rollover  . . . . . . . . . . . . . . .  11
     5.3.  DNS-over-TLS  . . . . . . . . . . . . . . . . . . . . . .  12
   6.  Logging and Monitoring  . . . . . . . . . . . . . . . . . . .  12
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   10. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  13
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     11.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Appendix A.  Standards Related to DNS Transport over TCP  . . . .  20
     A.1.  IETF RFC 1035 - DOMAIN NAMES - IMPLEMENTATION AND
           SPECIFICATION . . . . . . . . . . . . . . . . . . . . . .  20
     A.2.  IETF RFC 1536 - Common DNS Implementation Errors and
           Suggested Fixes . . . . . . . . . . . . . . . . . . . . .  20
     A.3.  IETF RFC 1995 - Incremental Zone Transfer in DNS  . . . .  20
     A.4.  IETF RFC 1996 - A Mechanism for Prompt Notification of
           Zone Changes (DNS NOTIFY) . . . . . . . . . . . . . . . .  20
     A.5.  IETF RFC 2181 - Clarifications to the DNS Specification .  21
     A.6.  IETF RFC 2694 - DNS extensions to Network Address
           Translators (DNS_ALG) . . . . . . . . . . . . . . . . . .  21
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