Internet DRAFT - draft-pfrc-2181-soa-records
draft-pfrc-2181-soa-records
INTERNET-DRAFT Declan Ma, Ed.
Intended Status: Proposed Standard zDNS Ltd.
Expires: 2015-10-15 2015-05-27
Issues Concerning DNS SOA Resource Records
draft-pfrc-2181-soa-records-00
Abstract
RFC 2181 collected eight independent considerations and created a single
docuement to address each of them in turn. Over the following two decades
it has become clear that each of these items should be considered and evovolve
in its own right, as suggested in RFC 2181. This document extracts the exact
text from RFC 2181 and places it into its own track.
Status of this Memo
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Internet-Drafts are working documents of the Internet Engineering
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Copyright and License Notice
Copyright (c) 2015 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
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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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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Placement of SOA RRs in authoritative answers . . . . . . . . . 3
4 TTLs on SOA RRs . . . . . . . . . . . . . . . . . . . . . . . . 3
5 The SOA.MNAME field . . . . . . . . . . . . . . . . . . . . . . 3
6 Security Considerations . . . . . . . . . . . . . . . . . . . . 3
7 References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 4
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1 Introduction
This document is intended to state three minor issues concerning DNS
SOA resource records and their use.
2 Terminology
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 RFC 2119 [RFC2119].
3 Placement of SOA RRs in authoritative answers
RFC1034, in section 3.7, indicates that the authority section of an
authoritative answer may contain the SOA record for the zone from
which the answer was obtained. When discussing negative caching,
RFC1034 section 4.3.4 refers to this technique but mentions the
additional section of the response. The former is correct, as is
implied by the example shown in section 6.2.5 of RFC1034. SOA
records, if added, are to be placed in the authority section.
4 TTLs on SOA RRs
the format of a Resource Record, that the definition of the TTL field
contains a throw away line which states that the TTL of an SOA record
should always be sent as zero to prevent caching. This is mentioned
nowhere else, and has not generally been implemented. Implementations
should not assume that SOA records will have a TTL of zero, nor are
they required to send SOA records with a TTL of zero.
5 The SOA.MNAME field
It is quite clear in the specifications, yet seems to have been
widely ignored, that the MNAME field of the SOA record should contain
the name of the primary (master) server for the zone identified by
the SOA. It should not contain the name of the zone itself. That
information would be useless, as to discover it, one needs to start
with the domain name of the SOA record - that is the name of the
zone.
6 Security Considerations
It may be observed that in section 3.2.1 of RFC1035, which defines
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the format of a Resource Record, that the definition of the TTL field
contains a throw away line which states that the TTL of an SOA record
should always be sent as zero to prevent caching. This is mentioned
nowhere else, and has not generally been implemented. Implementations
should not assume that SOA records will have a TTL of zero, nor are
they required to send SOA records with a TTL of zero.
7 References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2199] Ramos, A., "Request for Comments Summary RFC Numbers 2100-
2199", RFC 2199, January 1998.
8 Authors' Addresses
Declan Ma, Ed.
ZDNS Ltd.
4, South 4th Street, Zhongguancun,
Haidian, Beijing 100190,
China
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