[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00

Internet Engineering Task Force                    M. Parthasarathy, Ed.
Internet-Draft                                                Apple Inc.
Intended status: Standards Track                                P. Vixie
Expires: March 30, 2012                                              ISC
                                                      September 27, 2011



                      draft-mohan-dns-query-xml-00

Abstract

   This memo presents a technique for representing DNS messages using
   XML.  This enables DNS query transactions to be transported over
   HTTP/HTTPS.

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 http://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."

   This Internet-Draft will expire on March 30, 2012.

Copyright Notice

   Copyright (c) 2011 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.  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.




Parthasarathy & Vixie    Expires March 30, 2012                 [Page 1]


Internet-Draft                DNS QUERY XML               September 2011


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  3
   2.  Protocol Overview  . . . . . . . . . . . . . . . . . . . . . .  3
   3.  DNS XML Query  . . . . . . . . . . . . . . . . . . . . . . . .  3
   4.  XML Representation of DNS Message  . . . . . . . . . . . . . .  4
   5.  DNS Message Format . . . . . . . . . . . . . . . . . . . . . .  4
   6.  DNS Resource Record Format . . . . . . . . . . . . . . . . . .  7
   7.  Message Compression  . . . . . . . . . . . . . . . . . . . . .  8
   8.  Message Update . . . . . . . . . . . . . . . . . . . . . . . .  8
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  8
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   11. Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     12.1. Normative References . . . . . . . . . . . . . . . . . . .  9
     12.2. Informative References . . . . . . . . . . . . . . . . . .  9
   Appendix A.  Appendix A  . . . . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
































Parthasarathy & Vixie    Expires March 30, 2012                 [Page 2]


Internet-Draft                DNS QUERY XML               September 2011


1.  Introduction

   Domain Name System (DNS) is specified in RFC 1035 [RFC1035] and its
   security extensions (DNSSEC) are specified in RFC 4034 [RFC4034] and
   RFC 4035 [RFC4035].  DNSSEC provides origin authentication and
   integrity protection for DNS data.  While signing the authority data
   and verifying such signatures in recursive or stub validators are
   well understood and well solved problems, the channel between
   authority servers and validators is commonly unusable for DNSSEC-
   secured transactions due to overreach in customer premises equipment,
   firewalls, intrusion detection systems, and non-DNSSEC-aware
   recursive name servers operated by enterprises or service providers.
   HTTP [RFC2616] is known to work in such environments and has become
   the de facto tunneling protocol in the Internet.  To facilitate
   tunneling DNS messages over HTTP, this document describes a method of
   encoding a DNS message, including the resource records, as an XML
   object [XML].

1.1.  Requirements Language

   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].


2.  Protocol Overview

   In traditional DNS communication, the DNS stub resolver communicates
   with a recursive server which in turn communicates with the
   authoritative servers to fetch the DNS data.  To fetch the DNS XML
   data, the resolver communicates with a web server using HTTP/HTTPS.
   It issues a GET request with parameters using the URI format in
   [RFC2396] indicating the attributes of the query as it would do in a
   normal DNS query.  The web server on receiving the request retrieves
   the DNS data and formats in XML before sending it back to the
   resolver.  The resolver may issue multiple DNS queries either using a
   single or multiple TCP connection to the server whose details are
   beyond the scope of this document.


3.  DNS XML Query

   The resolver issues a HTTP GET request with parameters to fetch the
   DNS XML data.  The structure of the query is as follows:







Parthasarathy & Vixie    Expires March 30, 2012                 [Page 3]


Internet-Draft                DNS QUERY XML               September 2011


      https://server_address/dns_service/
      query?name=NAME&type=TYPE&ID=VALUE&RD=VALUE&CD=VALUE&DO=VALUE

         dns_service - tells the web server that the GET request is to
         fetch the DNS records

         query - indicates that this GET request is a DNS query and it
         should return the DNS Response formatted in XML

         name - The domain name being looked up

         type - Type of the query as specified under "TYPE" field in the
         RRTYPE registry in [IANA_DNS].

         ID - Corresponds to the ID value in the DNS query.  When there
         are multiple queries in flight, the ID in the response can be
         used to match the request.

         RD - Corresponds to the "RD" bit in the DNS query.  Set to 1 if
         recursion is desired or 0 otherwise.

         CD - Corresponds to the "CD" bit in the DNS query.  Set to 1 if
         validation will be done by the end host or 0 otherwise.

         DO - Corresponds to the "DNSSEC OK" bit in the DNS query.  It
         reflects the setting of the DNSSEC OK bit in EDNS0 option.


4.  XML Representation of DNS Message

   The XML representation of the DNS message maps the DNS header
   specified in section 4.1.1 of [RFC1035] to XML representation.


5.  DNS Message Format

   The DNS message is enclosed under the root element "response", under
   which all the other elements appear.

   <response>

         All the other elements are enclosed within this element.

   </response>

   The XML representation of the DNS header does not represent all the
   fields.  Only RCODE, the AA bit and the CD bit of the second sixteen
   bit field (that follows the ID field) is represented.  The fields



Parthasarathy & Vixie    Expires March 30, 2012                 [Page 4]


Internet-Draft                DNS QUERY XML               September 2011


   QDCOUNT and the question section are omitted.  If the resolver
   converts the XML representation into binary format for processing,
   the omitted fields should be inferred appropriately.  Rest of the
   fields are described below.

   <id>

         The value of this field is copied from the HTTP request
         parameters.  It is used by the resolver to match the response
         to the request.

   </id>

   <aa>

         Corresponds to the AA bit in the header.  If AA is set, this
         element is set to 1 and otherwise 0.

   </aa>

   <ad>

         Corresponds to the AD bit in the header.  If AD is set, this
         element is set to 1 and otherwise 0.

   </ad>

   <cd>

         Corresponds to the CD bit in the header.  If CD is set, this
         element is set to 1 and otherwise 0.

   </cd>

   <rcode>

         RCODE of the response represented as specified under "Name"
         field of the RCODE registry in [IANA_DNS].

   </rcode>

   <anscount>

         Number of answers in the answers element described below

   </anscount>

   <answers>



Parthasarathy & Vixie    Expires March 30, 2012                 [Page 5]


Internet-Draft                DNS QUERY XML               September 2011


      This section contains all the records in the answer section of the
      response with each resource record in the answer element.

         <answer>

               Each answer element contains a resource record

         </answer>

   </answers>

   <nscount>

         Number of authorities in the authorities element described
         below

   </nscount>

   <authorities>

      This section contains all the records in the authority section of
      the response with each resource record in the authority element.

         <authority>

               Each authority element contains a resource record

         </authority>

   </authorities>

   <arcount>

         Number of additional records in the additionals element given
         below

   </arcount>

   <additionals>

      This section contains all the records in the additional section of
      the response with each resource record in the additional element.

         <additional>







Parthasarathy & Vixie    Expires March 30, 2012                 [Page 6]


Internet-Draft                DNS QUERY XML               September 2011


               Each additional element contains a resource record

         </additional>

   </additionals>


6.  DNS Resource Record Format

   Every DNS resource record contains a name, type, class, ttl, rdlength
   and type specific rdata.  The XML elements for each of these are
   described below.

   <name>

         Textual representation of the domain name to which this
         resource record pertains as it appears in the master file

   </name>

   <type>

         Type of the RDATA field as specified under "TYPE" field in the
         RRTYPE registry in [IANA_DNS].

   </type>

   <class>

         Class of the RDATA field as specified under "Name" field in the
         Class registry in [IANA_DNS].

   </class>

   <ttl>

         Time to live value of this resource record in seconds

   </ttl>

   <rdlength>

         Length of the RDATA field

   </rdlength>

   <rdata>




Parthasarathy & Vixie    Expires March 30, 2012                 [Page 7]


Internet-Draft                DNS QUERY XML               September 2011


         RDATA is represented as zero or more words of hexadecimal data
         described in RFC 3597 [RFC3597].  The special token \# and
         RDATA length are not included.

   </rdata>


7.  Message Compression

   Message compression is not supported.  All names should be fully
   expanded.


8.  Message Update

   DNS Update RFC 2136 [RFC2136] is not supported.


9.  Acknowledgements

   TBD


10.  IANA Considerations

   This memo includes no request to IANA.


11.  Security Considerations

   In the current DNS system, there is no trust relationship between the
   stub resolver and the rest of the system.  When the users connect to
   the Internet using their ISP that provides the Internet service, they
   expect the ISP to provide trustworthy DNS service.  When they connect
   to the Internet from hotspots and other places, there is no trust
   whatsoever.  There are also many popular open recursive resolvers
   that are available in the Internet today that provide DNS resolution.
   Similarly, the DNS service described in this document may be provided
   via both HTTP and HTTPS.  Depending on the stub resolver's trust
   relationship with the DNS service provider, it can use HTTP or HTTPS.
   When DNSSEC is used, the DNS data can be authenticated independently.

   DNSSEC itself cannot be used to validate the IP address of the server
   that is providing the DNS service using the method described in this
   document.


12.  References



Parthasarathy & Vixie    Expires March 30, 2012                 [Page 8]


Internet-Draft                DNS QUERY XML               September 2011


12.1.  Normative References

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, November 1987.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3597]  Gustafsson, A., "Handling of Unknown DNS Resource Record
              (RR) Types", RFC 3597, September 2003.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, March 2005.

   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", RFC 4035, March 2005.

12.2.  Informative References

   [IANA_DNS]
              "Domain Name System Parameters",
              <http://www.iana.org/assignments/dns-parameters>.

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

   [RFC2396]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifiers (URI): Generic Syntax", RFC 2396,
              August 1998.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [XML]      T, Bray., J, Paoli., and Sperberg-McQueen. C.M.,
              "Extensible Markup Language (XML)", 1998.


Appendix A.  Appendix A

   This section provides a few sample queries and responses







Parthasarathy & Vixie    Expires March 30, 2012                 [Page 9]


Internet-Draft                DNS QUERY XML               September 2011


      QUERY: https://server_address/dns_service/
      query?name=www.isc.org&type=A&ID=2345&RD=1

      RESPONSE:

      <?xml version="1.0" encoding="US-ASCII"?>

      <response>

         <ID>2345</id>

         <aa>1</aa>

         <rcode>0</rcode>

         <anscount>1</anscount>

         <answers>

            <answer>9514402A</answer>

         </answers>

      </response>


Authors' Addresses

   Mohan Parthasarathy (editor)
   Apple Inc.
   1 Infinite loop
   Cupertino,   95014
   USA

   Phone: +1 408 862 7901
   Email: mparthasarathy@apple.com


   Paul Vixie
   ISC
   950 Charter Street
   Redwood City,   94063
   USA

   Phone: +1 650 423 1300
   Email: vixie@isc.org





Parthasarathy & Vixie    Expires March 30, 2012                [Page 10]


Html markup produced by rfcmarkup 1.123, available from https://tools.ietf.org/tools/rfcmarkup/