Serving Stale Data to Improve DNS Resiliency
draft-tale-dnsop-serve-stale-00
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DNSOP Working Group D. Lawrence
Internet-Draft Akamai Technologies
Intended status: Standards Track W. Kumari
Expires: September 14, 2017 Google
March 13, 2017
Serving Stale Data to Improve DNS Resiliency
draft-tale-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 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 September 14, 2017.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
Lawrence & Kumari Expires September 14, 2017 [Page 1]
Internet-Draft DNS Serve Stale March 2017
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
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Description . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Implementation Caveats . . . . . . . . . . . . . . . . . . . 4
5. Implementation Status . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 6
8. NAT Considerations . . . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
11.1. Normative References . . . . . . . . . . . . . . . . . . 6
11.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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].
Specifically, [RFC1035] Section 3.2.1 says that it "specifies the
time interval that the resource record may be cached before the
source of the information should again be consulted".
Notably, the original DNS specification does not say that data past
its expiration cannot be used. This document proposes a method for
how recursive resolvers should handle stale DNS data to balance the
competing needs of resiliency and freshness. 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.
There are a number of reasons why an authoritative server may become
unreachable, including Denial of Service (DoS) attacks, network
issues, and so on. This document suggests that, if the recursive
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