A Common Operational Problem in DNS Servers - Failure To Respond.
draft-ietf-dnsop-no-response-issue-00

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Document Type Active Internet-Draft (dnsop WG)
Author Mark Andrews 
Last updated 2015-11-28
Replaces draft-andrews-dns-no-response-issue
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Network Working Group                                         M. Andrews
Internet-Draft                                                       ISC
Intended status: Best Current Practice                 November 28, 2015
Expires: May 31, 2016

   A Common Operational Problem in DNS Servers - Failure To Respond.
                 draft-ietf-dnsop-no-response-issue-00

Abstract

   The DNS is a query / response protocol.  Failure to respond or to
   respond correctly to queries causes both immediate operational
   problems and long term problems with protocol development.

   This document identifies a number of common classes of queries to
   which some servers either fail to respond or else respond
   incorrectly.  This document also suggests procedures for TLD and
   other similar zone operators to apply to help reduce / eliminate the
   problem.

   The document does not look at the DNS data itself, just the structure
   of the responses.

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
   working documents as Internet-Drafts.  The list of current Internet-
   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 31, 2016.

Copyright Notice

   Copyright (c) 2015 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

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   (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
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Common queries class that result in non responses.  . . . . .   3
     2.1.  EDNS Queries - Version Independent  . . . . . . . . . . .   4
     2.2.  EDNS Queries - Version Specific . . . . . . . . . . . . .   4
     2.3.  EDNS Options  . . . . . . . . . . . . . . . . . . . . . .   4
     2.4.  EDNS Flags  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.5.  DNS Flags . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.6.  Unknown / Unsupported Type Queries  . . . . . . . . . . .   5
     2.7.  Unknown DNS opcodes . . . . . . . . . . . . . . . . . . .   5
     2.8.  TCP Queries . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Remediating . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Firewalls and Load Balancers  . . . . . . . . . . . . . . . .   7
   5.  Scrubbing Services  . . . . . . . . . . . . . . . . . . . . .   8
   6.  Whole Answer Caches . . . . . . . . . . . . . . . . . . . . .   9
   7.  Response Code Selection . . . . . . . . . . . . . . . . . . .   9
   8.  Testing . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Testing - Basic DNS . . . . . . . . . . . . . . . . . . .  10
     8.2.  Testing - Extended DNS  . . . . . . . . . . . . . . . . .  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   The DNS [RFC1034], [RFC1035] is a query / response protocol.  Failure
   to respond to queries or to respond incorrectly causes both immediate
   operational problems and long term problems with protocol
   development.

   Failure to respond to a query is indistinguishable from a packet loss
   without doing a analysis of query response patterns and results in
   unnecessary additional queries being made by DNS clients and
   unnecessary delays being introduced to the resolution process.

   Due to the inability to distinguish between packet loss and
   nameservers dropping EDNS [RFC6891] queries, packet loss is sometimes

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   misclassified as lack of EDNS support which can lead to DNSSEC
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