Returning extra answers in DNS responses.
draft-wkumari-dnsop-multiple-responses-05

Document Type Active Internet-Draft (dnsop WG)
Last updated 2017-07-03
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dnsop                                                          W. Kumari
Internet-Draft                                                    Google
Intended status: Standards Track                                  Z. Yan
Expires: January 4, 2018                                           CNNIC
                                                             W. Hardaker
                                                                 USC/ISI
                                                             D. Lawrence
                                                     Akamai Technologies
                                                            July 3, 2017

               Returning extra answers in DNS responses.
               draft-wkumari-dnsop-multiple-responses-05

Abstract

   This document (re)introduces the ability to provide multiple answers
   in a DNS response.  This is especially useful as, in many cases, the
   entity making the request has no a prori knowledge of what other
   questions it will need to ask.

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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   This Internet-Draft will expire on January 4, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (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

Kumari, et al.           Expires January 4, 2018                [Page 1]
Internet-Draft              DNS Extra Answers                  July 2017

   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
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   3
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Returning multiple answers  . . . . . . . . . . . . . . . . .   4
   5.  The EXTRA Resource Record . . . . . . . . . . . . . . . . . .   5
     5.1.  File Format . . . . . . . . . . . . . . . . . . . . . . .   5
     5.2.  Wire Format . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Signaling support . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Stub-Resolver Considerations  . . . . . . . . . . . . . . . .   6
   8.  Use of Additional information . . . . . . . . . . . . . . . .   6
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   10. Security Considerations . . . . . . . . . . . . . . . . . . .   7
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   12. Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Appendix A.  Changes / Author Notes.  . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   In many cases a name being resolved in the DNS provides the reason
   behind why the name is being resolved.  This may allow the
   authoritative nameserver to predict what other answers a recursive
   resolver will soon query for.  By providing multiple answers in the
   response, the authoritative name server operator can assist a caching
   recursive resolver in pre-populating its cache before a stub resolver
   or other client asks for the subsequent queries.  Apart from
   decreasing the latency for end users [RFC6555], this also decreases
   the total number of queries that the recursive resolver needs to send
   and the authoritative server needs to answer.

   For example, the domain name administrator of Example Widgets, Inc
   (example.com) knows that the web page at www.example.com contains
   various other resources, including some images (served from
   images.example.com), some Cascading Style Sheets (served from
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