Serving Stale Data to Improve DNS Resiliency
draft-ietf-dnsop-serve-stale-05
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Active Internet-Draft (dnsop WG)
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2019-07-02
(latest revision 2019-04-16)
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draft-tale-dnsop-serve-stale
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IETF
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(None)
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WG state
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WG Document
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Document shepherd |
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Suzanne Woolf
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Send notices to |
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Suzanne Woolf <suzworldwide@gmail.com>
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DNSOP Working Group D. Lawrence
Internet-Draft Oracle
Updates: 1034, 1035 (if approved) W. Kumari
Intended status: Standards Track P. Sood
Expires: October 18, 2019 Google
April 16, 2019
Serving Stale Data to Improve DNS Resiliency
draft-ietf-dnsop-serve-stale-05
Abstract
This draft defines a method (serve-stale) for recursive resolvers to
use stale DNS data to avoid outages when authoritative nameservers
cannot be reached to refresh expired data. It updates the definition
of TTL from [RFC1034], [RFC1035], and [RFC2181] to make it clear that
data can be kept in the cache beyond the TTL expiry and used for
responses when a refreshed answer is not readily available. One of
the motivations for serve-stale is to make the DNS more resilient to
DoS attacks, and thereby make them less attractive as an attack
vector.
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."
Lawrence, et al. Expires October 18, 2019 [Page 1]
Internet-Draft DNS Serve Stale April 2019
This Internet-Draft will expire on October 18, 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
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Standards Action . . . . . . . . . . . . . . . . . . . . . . 4
5. Example Method . . . . . . . . . . . . . . . . . . . . . . . 4
6. Implementation Considerations . . . . . . . . . . . . . . . . 6
7. Implementation Caveats . . . . . . . . . . . . . . . . . . . 8
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 9
9. EDNS Option . . . . . . . . . . . . . . . . . . . . . . . . . 10
10. Security Considerations . . . . . . . . . . . . . . . . . . . 10
11. Privacy Considerations . . . . . . . . . . . . . . . . . . . 10
12. NAT Considerations . . . . . . . . . . . . . . . . . . . . . 11
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
15.1. Normative References . . . . . . . . . . . . . . . . . . 11
15.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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
Lawrence, et al. Expires October 18, 2019 [Page 2]
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