Title
draft-bellis-dnsext-multi-qtypes-00

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Document Type Active Internet-Draft (individual)
Author Ray Bellis 
Last updated 2012-03-27
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Network Working Group                                          R. Bellis
Internet-Draft                                                Nominet UK
Intended status: Standards Track                          March 27, 2012
Expires: September 28, 2012

                                 Title
                  draft-bellis-dnsext-multi-qtypes-00

Abstract

   This document specifies a method for a DNS client to request
   additional DNS record types to be delivered alongside the primary
   record type specified in the question section of a DNS query.

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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   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 September 28, 2012.

Copyright Notice

   Copyright (c) 2012 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
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   described in the Simplified BSD License.

Bellis                 Expires September 28, 2012               [Page 1]
Internet-Draft                    Title                       March 2012

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3

   2.  Terminology used in this document . . . . . . . . . . . . . . . 3

   3.  Description . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  Multiple QTYPE EDNS Option Format . . . . . . . . . . . . . 3
     3.2.  Response Generation . . . . . . . . . . . . . . . . . . . . 4
       3.2.1.  Server Side Processing  . . . . . . . . . . . . . . . . 4
       3.2.2.  Client Side Processing  . . . . . . . . . . . . . . . . 5
       3.2.3.  DNSSEC  . . . . . . . . . . . . . . . . . . . . . . . . 5

   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6

   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6

   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6

   7.  Normative References  . . . . . . . . . . . . . . . . . . . . . 6

   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . . . 7

   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7

Bellis                 Expires September 28, 2012               [Page 2]
Internet-Draft                    Title                       March 2012

1.  Introduction

   A commonly requested DNS [RFC1035] feature is the ability to receive
   multiple related resource records (RRs) in a single DNS response.

   For example, it may be desirable to receive both the A and AAAA
   records for a domain name together, rather than having to issue
   multiple queries.

   The DNS wire protocol in theory supports having multiple questions in
   a single packet, but in practise this does not work:

   o  Each question consists of the tuple (QNAME, QTYPE, QCLASS).  Since
      each question has its own QNAME field it would be possible for one
      name to exist and another to not exist, resulting in an
      inconsistent response code.
   o  The idea that only a single question is allowed is sufficiently
      entrenched that many DNS servers will simply return an error (or
      fail to response at all) if they receive a query with a question
      count (QDCOUNT) of more than one.

   To resolve both of these issues, this document constraints the
   problem to those cases where only the QTYPE varies by specifying a
   new option for the Extension Mechanisms for DNS (EDNS [RFC2671]) that
   contains an additional list of QTYPE values that the client wishes to
   receive in addition to that in the primary question.

   TODO: why not "ANY" ?

2.  Terminology used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

3.  Description

3.1.  Multiple QTYPE EDNS Option Format

   The overall format of an EDNS option is shown for reference below,
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