Network Working Group                                         M. Andrews
Internet-Draft                                                       ISC
Expires: April 12, 2014                                  October 9, 2013


                         Updating Parent Zones
               draft-andrews-dnsop-update-parent-zones-01

Abstract

   DNS UPDATE was developed to allow DNS zones to be updated.

   There is a perception that UPDATE can not be used in conjuction with
   the Registry, Registar, Registrant (RRR) model to update a zone.

   This document explains how UPDATE can be used in the RRR model.

Status of this Memo

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   This Internet-Draft will expire on April 12, 2014.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Translation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Authentication  . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Direct to Registrar . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Indirect to Registrar . . . . . . . . . . . . . . . . . . . . . 4
   6.  UPDATE Server Discovery . . . . . . . . . . . . . . . . . . . . 4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   8.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 5








































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1.  Introduction

   UPDATE [RFC2136]is designed to update any zone in the DNS.  This
   includes updating delegating NS records, glue address records and DS
   record.

   While UPDATE is primarily designed to UPDATE a zone directly there in
   no reason why UPDATE requests cannot be translated to the EPP
   requests to perform the changes.

   This would provide a uniform model to update parent zone regardless
   of where they are in the DNS heirachy.


2.  Translation

   The Registrar would host a server that authenticates UPDATE requests
   received directly or relayed by the Registry using TSIG [RFC2845],
   then translate the actions in the UPDATE request into EPP transaction
   requests.  The results of those EPP transactions would be relayed to
   the UPDATE client.

   Requests that are not TSIG signed are rejected.

   The translating server would handle a restricted subset of UPDATE
   requests, possibly ignoring the prerequiste section.  UPDATE requests
   would be limited to those supported by EPP.

   e.g.  Add NS record.  Delete all NS records.  Add A record.  Delete
   AAAA record.  Add DS record.  Delete DS record.

   The translating server may also override/ignore the TTL in the UPDATE
   request.


3.  Authentication

   Authentication would be done using TSIG.  TSIG was designed to be
   used in a environment where requests are relayed.

   Authentication can be done down to the <NAME,TYPE> tuple.  There
   exist nameservers that already implement access contols down to this
   level of granuality based on the presented TSIG.

   This would allow nameservers to update their own address records as
   they get renumbered without being able to update anything else.

   This would allow DNSSEC key management software to update DS records



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   without being able to update anything else.

   As Registrars do all the authentication and generate the signed
   responses there is no need for the Registry to have access to the
   private material using in TSIG.  Registrars already handle shared
   keys in these numbers with their web interfaces.


4.  Direct to Registrar

   The hardest part of Direct to Registrar is finding where to send the
   UPDATE request.  This would most probably just be advised to the
   Registrant.


5.  Indirect to Registrar

   In the indirect model the Registry would host a UPDATE relay server
   which would examine the first record of the UPDATE section and relay
   the request to the Registrar of record for the owner name of that
   record.  The response would be relayed back.

   The relay can use either TCP or UDP when forwarding UPDATE requests
   as TSIG supports changes to the DNS id field when a request/response
   is relayed.

   This is consistent with how tools like nsupdate work out where to
   send a UPDATE request.  They look at the ownername of the first
   record and use it to discover the containing zone.


6.  UPDATE Server Discovery

   UPDATE server discovery is a issue when the RRR model is in use as
   the UPDATE may need to be directed through EPP and/or a sent to a
   Registrar.  There are a number of way this could be done.

   Adding a underscore infix labels to the zone which contain SRV
   records at pointing to Registar/Registry servers for each child.

   e.g. <child>._update._tcp.<parent> SRV 0 0 0 server.example.tld

   The servers pointed could be be a relay server, as described above,
   or a UDPATE to EPP translating server.  A relay server would allow
   for slower zone growth.

   Using underscore infix labels requires no changes to nameservers
   operated by Registries but does require the zone content to be



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   updated.

   Extend UDPATE to return the update server.  Currently the Zone
   section of the UPDATE refers to the zone to be update and is
   identified by the <QNAME,SOA,QCLASS> tuple.  Replacing SOA with one
   or more of DS, NS, A and AAAA would allow a nameserver to distingish
   between a traditional UPDATE request and a request to find the UPDATE
   servers.  The tuple would contain the resource to be updated and the
   reply would contain SRV records pointing to the UPDATE servers.  As
   there would possibly more than one parent the owner records would
   refer to the parent zone being updated.

   One could use a new OPCODE for UPDATE server discovery.


7.  Security Considerations

   The UPDATE requests are all TSIG signed.  This is a proven method for
   securing UPDATE requests in the DNS.


8.  Normative References

   [RFC2136]  Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
              "Dynamic Updates in the Domain Name System (DNS UPDATE)",
              RFC 2136, April 1997.

   [RFC2845]  Vixie, P., Gudmundsson, O., Eastlake, D., and B.
              Wellington, "Secret Key Transaction Authentication for DNS
              (TSIG)", RFC 2845, May 2000.


Author's Address

   M. Andrews
   Internet Systems Consortium
   950 Charter Street
   Redwood City, CA  94063
   US

   Email: marka@isc.org










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