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

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
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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
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   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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