Serving Stale Data to Improve DNS Resiliency
draft-ietf-dnsop-serve-stale-00

Document Type Active Internet-Draft (dnsop WG)
Last updated 2017-10-30
Replaces draft-tale-dnsop-serve-stale
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DNSOP Working Group                                          D. Lawrence
Internet-Draft                                       Akamai Technologies
Updates: 1034, 1035 (if approved)                              W. Kumari
Intended status: Standards Track                                  Google
Expires: May 3, 2018                                    October 30, 2017

              Serving Stale Data to Improve DNS Resiliency
                    draft-ietf-dnsop-serve-stale-00

Abstract

   This draft defines a method for recursive resolvers to use stale DNS
   data to avoid outages when authoritative nameservers cannot be
   reached to refresh expired data.

Ed note

   Text inside square brackets ([]) is additional background
   information, answers to frequently asked questions, general musings,
   etc.  They will be removed before publication.  This document is
   being collaborated on in GitHub at <https://github.com/vttale/serve-
   stale>.  The most recent version of the document, open issues, etc
   should all be available here.  The authors gratefully accept pull
   requests.

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 May 3, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Lawrence & Kumari          Expires May 3, 2018                  [Page 1]
Internet-Draft               DNS Serve Stale                October 2017

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (https://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Standards Action  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  EDNS Option . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Option Format . . . . . . . . . . . . . . . . . . . . . .   4
     5.2.  Option Usage  . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Example Method  . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Implementation Caveats  . . . . . . . . . . . . . . . . . . .   7
   8.  Implementation Status . . . . . . . . . . . . . . . . . . . .   8
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   10. Privacy Considerations  . . . . . . . . . . . . . . . . . . .   9
   11. NAT Considerations  . . . . . . . . . . . . . . . . . . . . .   9
   12. IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     14.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     14.2.  Informative References . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Traditionally the Time To Live (TTL) of a DNS resource record has
   been understood to represent the maximum number of seconds that a
   record can be used before it must be discarded, based on its
   description and usage in [RFC1035] and clarifications in [RFC2181].

   This document proposes that the definition of the TTL be explicitly
   expanded to allow for expired data to be used in the exceptional
   circumstance that a recursive resolver is unable to refresh the
   information.  It is predicated on the observation that authoritative
   server unavailability can cause outages even when the underlying data
   those servers would return is typically unchanged.

   A method is described for this use of stale data, balancing the
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