ATR: Additional Truncation Response for Large DNS Response
draft-song-atr-large-resp-03

Document Type Active Internet-Draft (individual)
Last updated 2019-04-23 (latest revision 2019-03-08)
Stream ISE
Intended RFC status Informational
Formats plain text xml pdf html bibtex
Stream ISE state Submission Received
Revised I-D Needed
Consensus Boilerplate Unknown
Document shepherd Adrian Farrel
IESG IESG state I-D Exists::Revised I-D Needed
Telechat date
Responsible AD (None)
Send notices to Adrian Farrel <rfc-ise@rfc-editor.org>
Internet Engineering Task Force                                  L. Song
Internet-Draft                                Beijing Internet Institute
Intended status: Informational                                   S. Wang
Expires: September 9, 2019                     Beijing Normal University
                                                           March 8, 2019

       ATR: Additional Truncation Response for Large DNS Response
                      draft-song-atr-large-resp-03

Abstract

   As the increasing use of DNSSEC and IPv6, there are more public
   evidence and concerns on IPv6 fragmentation issues due to larger DNS
   payloads over IPv6.  This memo introduces an simple improvement on
   DNS server by replying an additional truncated response just after
   the normal fragmented response.  It can be used to relieve users
   suffering on DNS latency and failures due to large DNS response.  An
   ATR Experiment was done to show how well it works and some
   operational issues are discussed in this memo as well.

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 https://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 September 9, 2019.

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

Song & Wang             Expires September 9, 2019               [Page 1]
Internet-DraATR: Additional Truncation Response for Large DN  March 2019

   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.  The ATR mechanism . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Experiment on how well ATR works  . . . . . . . . . . . . . .   5
   4.  Operational considerations  . . . . . . . . . . . . . . . . .   6
     4.1.  ATR timer . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  ATR payload size  . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Less aggressiveness of ATR  . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  IANA considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
   Appendix A.  Considerations on Resolver awareness of ATR  . . . .  11
   Appendix B.  Revision history of this document  . . . . . . . . .  11
     B.1.  draft-song-atr-large-resp-01  . . . . . . . . . . . . . .  11
     B.2.  draft-song-atr-large-resp-02  . . . . . . . . . . . . . .  12
     B.3.  draft-song-atr-large-resp-03  . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   Large DNS response is identified as a issue for a long time.  There
   is an inherent mechanism defined in [RFC1035] to handle large DNS
   response (larger than 512 octets) by indicating (set TrunCation bit)
   the resolver to fall back to query via TCP.  Due to the fear of cost
   of TCP, EDNS(0) [RFC6891] was proposed which encourages server to
   response larger response instead of falling back to TCP.  However, as
   the increasing use of DNSSEC and IPv6, there are more public
   evidence[DNSSEC-impact] and concerns on user's suffering due to
   packets dropping caused by IPv6 fragmentation in DNS due to large DNS
   response.

   It is observed that some IPv6 network devices like firewalls
   intentionally choose to drop the IPv6 packets with fragmentation
   Headers[I-D.taylor-v6ops-fragdrop].  [RFC7872] reported more than 30%
   drop rates for sending fragmented packets.  Regarding IPv6
   fragmentation issue due to larger DNS payloads in response, one
   measurement [IPv6-frag-DNS] reported 35% of endpoints using
   IPv6-capable DNS resolver can not receive a fragmented IPv6 response
Show full document text