Extension Mechanisms for DNS (EDNS) EXPIRE Option
RFC 7314
| Document | Type |
RFC - Experimental
(July 2014; No errata)
Was draft-andrews-dnsext-expire (individual)
|
|
|---|---|---|---|
| Last updated | 2014-07-17 | ||
| Stream | ISE | ||
| Formats | plain text pdf html bibtex | ||
| IETF conflict review | conflict-review-andrews-dnsext-expire | ||
| Stream | ISE state | Published RFC | |
| Consensus Boilerplate | Unknown | ||
| Document shepherd | Nevil Brownlee | ||
| Shepherd write-up | Show (last changed 2014-03-27) | ||
| IESG | IESG state | RFC 7314 (Experimental) | |
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA action state | RFC-Ed-Ack | ||
Independent Submission M. Andrews
Request for Comments: 7314 ISC
Category: Experimental July 2014
ISSN: 2070-1721
Extension Mechanisms for DNS (EDNS) EXPIRE Option
Abstract
This document specifies a method for secondary DNS servers to honour
the SOA EXPIRE field as if they were always transferring from the
primary, even when using other secondaries to perform indirect
transfers and refresh queries.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This is a contribution to the RFC Series, independently
of any other RFC stream. The RFC Editor has chosen to publish this
document at its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7314.
Copyright Notice
Copyright (c) 2014 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
to this document.
Andrews Experimental [Page 1]
RFC 7314 Extension Mechanisms for DNS (EDNS) EXPIRE Option July 2014
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Reserved Words . . . . . . . . . . . . . . . . . . . . . 2
2. Expire EDNS Option (Query) . . . . . . . . . . . . . . . . . 3
3. Expire EDNS Option (Response) . . . . . . . . . . . . . . . . 3
3.1. Primary Server . . . . . . . . . . . . . . . . . . . . . 3
3.2. Secondary Server . . . . . . . . . . . . . . . . . . . . 3
3.3. Non-authoritative Server . . . . . . . . . . . . . . . . 3
4. Secondary Behaviour . . . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The expire field of a DNS zone's SOA record [RFC1035] is supposed to
indicate when a secondary server shall discard the contents of the
zone when it has been unable to contact the primary [RFC1034].
Current practice only works when all the secondaries contact the
primary directly to perform refresh queries and zone transfers.
While secondaries are expected to be able to, and often are
configured to, transfer from other secondaries for robustness reasons
as well as reachability constraints, there is no mechanism provided
to preserve the expiry behaviour when using a secondary. Instead,
secondaries have to know whether they are talking directly to the
primary or another secondary and use that to decide whether or not to
update the expire timer. This, however, fails to take into account
delays in transferring from one secondary to another.
There are also zone-transfer graphs in which the secondary never
talks to the primary, so the effective expiry period becomes
multiplied by the length of the zone-transfer graph, which is
infinite when it contains loops.
This document provides a mechanism to preserve the expiry behaviour
regardless of what zone-transfer graph is constructed and whether the
secondary is talking to the primary or another secondary.
1.1. Reserved Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
Andrews Experimental [Page 2]
RFC 7314 Extension Mechanisms for DNS (EDNS) EXPIRE Option July 2014
2. Expire EDNS Option (Query)
The EDNS [RFC6891] EXPIRE option has the value <9>. The EDNS EXPIRE
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