Independent Submission T. Manderson
Request for Comments: 7745 ICANN
Category: Informational January 2016
ISSN: 2070-1721
XML Schemas for Reverse DNS Management
Abstract
This document defines an Extensible Markup Language (XML) schema for
reverse DNS management in a tightly controlled Representational State
Transfer (REST) environment. This document describes a schema that
has been developed and deployed by ICANN in a "RESTful" system since
2011 and is being used by the registries responsible for reverse DNS
(rDNS) delegations underneath IN-ADDR.ARPA and IP6.ARPA through an
HTTPS transaction that is mediated by an X.509 certificate.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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/rfc7745.
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Manderson Informational [Page 1]
RFC 7745 XML Schemas for rDNS Management January 2016 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 3. Implementation . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Normative References . . . . . . . . . . . . . . . . . . 5 5.2. Informative References . . . . . . . . . . . . . . . . . 6 Appendix A. Schema Definition for rDNS Updates . . . . . . . . . 7 Appendix B. Schema Definition for rDNS Queue Entries . . . . . . 8 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 10 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction This document defines an Extensible Markup Language (XML) schema for reverse DNS management in a tightly controlled Representational State Transfer (REST) [REST] environment. This document describes a schema that has been developed and deployed by ICANN in a "RESTful" system since 2011 and is being used by the registries responsible for reverse DNS (rDNS) delegations underneath IN-ADDR.ARPA [RFC1034] and IP6.ARPA [RFC3596] through an HTTPS [RFC2818] transaction that is mediated by an X.509 [RFC5280] certificate. As DNSSEC [RFC4033] adoption progresses, the necessity to interact with a delegation in the IN-ADDR.ARPA and IP6.APRA zones becomes more frequent given that updates to DS records in the parent zone for child delegations follow the key rollover and expiry of the child zone. The modification of such critical areas at a relative high frequency requires a system that allows the administrative holders of such delegations to make such changes in a secure and trustworthy manner where the chain of trust for submitting the necessary information remains unbroken between the IN-ADDR.ARPA and IP6.APRA zone maintainers and the zone customers. At the request of the Regional Internet Registries (RIRs) to automate reverse DNS updates with ICANN, a REST-based HTTPS service was deployed that: o Provides for a secure, authenticated mechanism to update zone data (NS and DS records) o Provides a well-formed data structure for both the IN-ADDR.ARPA and IP6.ARPA zones o Allows for "out-of-band" acknowledgement and notification of updates Manderson Informational [Page 2]
RFC 7745 XML Schemas for rDNS Management January 2016 2. 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]. 3. Implementation The implemented system allows the entity responsible for its rDNS delegations to effect changes in the reverse DNS zones IN-ADDR.ARPA and IP6.ARPA by submitting an XML document to an atomic RESTful service via an HTTPS [RFC2818] connection. In this service, the HTTPS layer provides the end-to-end security of the transaction, and it further provides authentication by use of mandatory X.509 [RFC5280] client certificates with a known server certificate issued by a Certification Authority administered by the service operator. Certificates for use in this system, issued by the system operator, are specific to the entity responsible for the delegations in the zone. Updates are made to the system by using the HTTP GET, PUT, and DELETE operations over HTTP 1.1 [RFC7231] via HTTPS [RFC2818] only. These operations are sent to a resource Uniform Resource Identifier (URI) in the form of: https://host.example.org/<ipversion>/<zone> A synthetic example of an XML document submitted to the deployed system might take the following form (including all optional attributes) as per the schema in Appendix A. Manderson Informational [Page 3]
RFC 7745 XML Schemas for rDNS Management January 2016 <zone xmlns="http://download.research.icann.org/rdns/1.1" name="10.in-addr.arpa" cust="IANA" ipversion="ipv4" version="1.1" modified="2012-01-18T01:00:06" state="active" href="https://host.example.org/ipv4/10"> <nserver> <fqdn>BLACKHOLE-1.IANA.ORG.</fqdn> </nserver> <nserver> <fqdn>BLACKHOLE-2.IANA.ORG.</fqdn> </nserver> <ds> <rdata>33682 5 1 ea8afb5fce7caf381ab101039</rdata> </ds> <ds> <rdata>33682 5 2 7d44874f1d93aaceb793a88001739a</rdata> </ds> </zone> When PUT and DELETE operations are used, the well-formed XML is required to be sent with the appropriate content-length headers. The GET operation requires only the URI. One requirement of the system was to allow the separation of update and approval with an out-of-band notification mechanism. When such options are configured for a customer of the service, submitted updates may be queued for later approval. When a customer has queued updates pending approval, the customer may submit a GET request to retrieve either an individual entry or a full listing of all queued entries. To fetch a listing of the customer's queue, the customer would GET a URI in the form of: https://host.example.org/queuelist To fetch an individual queue entry, the customer would GET the canonical URL (as per the schema) for this queue record: https://host.example.org/queue/<identifier> Where <identifier> is a system-generated and system-specific value that identifies this particular queue entry. All XML returned from queue-based operations ('queue' and 'queuelist') would return an XML document following the specification in Appendix B. A synthetic example from a GET of 'queuelist' would be: Manderson Informational [Page 4]
RFC 7745 XML Schemas for rDNS Management January 2016 <queuelist xmlns="http://download.research.icann.org/rq/1.0" version="1.0"> <queue xmlns="http://download.research.icann.org/rq/1.0" name="10.in-addr.arpa" cust="IANA" ipversion="ipv4" version="1.0" submitted="2013-01-11T05:22:15" state="pending" method="PUT" ack="https://host.example.org/ack/25a531f50e5ba45" href="https://host.example.org/queue/25a531f50e5ba45"> <nserver> <fqdn>BLACKHOLE-1.IANA.ORG.</fqdn> </nserver> <nserver> <fqdn>BLACKHOLE-2.IANA.ORG.</fqdn> </nserver> <ds> <rdata>33682 5 1 ea8afb5fce7caf381ab101039</rdata> </ds> <ds> <rdata>33682 5 2 7d44874f1d93aaceb793a88001739a</rdata> </ds> </queue> </queuelist> 4. Security Considerations This document provides an XML schema for facilitating the management of reverse DNS delegations in the IN-ADDR.ARPA and IP6.APRA zones. The schema itself contains no authentication data, and all other information contained is considered public data as it is either published in DNS or propagated to other public information sources like WHOIS. The system that implements this XML schema requires HTTPS to be used and also uses known server and client X.509 certificates for authentication to protect against message modification, message insertion/deletion, man-in-the-middle, and replay attacks. Any DoS-type attack vectors and the authorisation of which delegations the X.509 certificate authentication sessions can affect are out of scope for this document. 5. References 5.1. Normative References [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, <http://www.rfc-editor.org/info/rfc1034>. Manderson Informational [Page 5]
RFC 7745 XML Schemas for rDNS Management January 2016 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, DOI 10.17487/RFC2818, May 2000, <http://www.rfc-editor.org/info/rfc2818>. [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS Extensions to Support IP Version 6", RFC 3596, DOI 10.17487/RFC3596, October 2003, <http://www.rfc-editor.org/info/rfc3596>. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, DOI 10.17487/RFC4033, March 2005, <http://www.rfc-editor.org/info/rfc4033>. [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, <http://www.rfc-editor.org/info/rfc5280>. [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content", RFC 7231, DOI 10.17487/RFC7231, June 2014, <http://www.rfc-editor.org/info/rfc7231>. 5.2. Informative References [RELAXNG] The Organization for the Advancement of Structured Information Standards (OASIS), "RELAX NG Compact Syntax", November 2002, <https://www.oasis-open.org/committees/ relax-ng/compact-20021121.html>. [REST] Fielding, R., "Architectural Styles and the Design of Network-based Software Architectures", PhD Dissertation, University of California, Irvine, ISBN 0-599-87118-0, 2000. Manderson Informational [Page 6]
RFC 7745 XML Schemas for rDNS Management January 2016 Appendix A. Schema Definition for rDNS Updates The following Schema, used for PUT, GET, and DELETE operations, is an XML document using the RelaxNG Compact [RELAXNG] specification. default namespace = "http://download.research.icann.org/rdns/1.1" # A document may either be a single zone (update) or # a collection of zones (view) start = zone | zonelist | zonereflist # A list of zone names for view only. zonereflist = element zonereflist { attribute version { xsd:decimal { minInclusive="1.1" fractionDigits="1" } }, zoneref* } # A bulk list of zones for view only. zonelist = element zonelist { attribute version { xsd:decimal { minInclusive="1.1" fractionDigits="1" } }, zone* } # A zone reference (accepted by REST engine for query) zoneref = element zoneref { attribute name { text }, attribute href { xsd:anyURI } } # A single zone record zone = element zone { # The zone record's name, e.g., 10.in-addr.arpa attribute name { text }, # The customer (optional); derived from known state. attribute cust { text }?, # The canonical URL for this zone record (optional) attribute href { xsd:anyURI }?, # The IP version of the address for the zone record (optional) attribute ipversion { "ipv4" | "ipv6" }?, # The administrative state of the zone (optional) attribute state { "active" | "pending" | "error" }?, # The last modified timestamp in UTC (optional) attribute modified { xsd:dateTime }?, # The schema version (optional) Manderson Informational [Page 7]
RFC 7745 XML Schemas for rDNS Management January 2016 attribute version { xsd:decimal { minInclusive="1.1" fractionDigits="1" } }?, # A zone NS RRset MUST have at least two NS records nserver, nserver+, # It MAY contain some DS records ds* } # DNS-SEC records ds = element ds { # rdata MUST contain # <Keytag> | <Algorithm> | <Digest type> | <Digest> # as per RFC 4034 # element rdata { text } } # A single name server nserver = element nserver { # An nserver entry MUST contain a DNS FQDN # for a NS RR (RFC 1035) element fqdn { text } } Appendix B. Schema Definition for rDNS Queue Entries The XML schema definition below, in RelaxNG Compact [RELAXNG] form is used for queue interaction operations. default namespace = "http://download.research.icann.org/rq/1.0" # A document MAY either be a single queue entry # or a collection of queued entries start = queue | queuelist # A list of zone names for view only. queuelist = element queuelist { attribute version { xsd:decimal { minInclusive="1.0" fractionDigits="0" } }, queue* } Manderson Informational [Page 8]
RFC 7745 XML Schemas for rDNS Management January 2016 # A single queued zone record queue = element queue { # The zone record's name, e.g., 10.in-addr.arpa attribute name { text }, # The customer (optional); derived from known state. attribute cust { text }?, # The canonical URL for this queue record (optional) attribute href { xsd:anyURI }?, # The acknowledgement URL for this queue record (optional) attribute ack { xsd:anyURI }?, # The IP version of the address for the zone record (optional) attribute ipversion { "ipv4" | "ipv6" }?, # The state of the zone (optional); for a queue, it # SHOULD always be pending attribute state { "pending" }?, # The submitted timestamp (optional) attribute submitted { xsd:dateTime }?, # The HTTP method used to update attribute method { "PUT" | "DELETE" }, # The schema version (1.0) (optional) attribute version { xsd:decimal { minInclusive="1.0" fractionDigits="1" } }?, # A zone NS RRset must have at least two NS records nserver, nserver+, # It MAY contain some DS records ds* } # DNS-SEC records ds = element ds { # rdata MUST contain Flags | Protocol | Algorithm | Public Key # as per RFC 4034 # element rdata { text } } # A single name server nserver = element nserver { # An nserver entry MUST contain a DNS FQDN # for a NS RR (RFC 1035) element fqdn { text } } Manderson Informational [Page 9]
RFC 7745 XML Schemas for rDNS Management January 2016
Acknowledgements
An XML schema was initially provided by APNIC; however, necessity
required a branch, and as such a new namespace and schema have been
created. Recognition goes to APNIC for prior efforts in this area.
The author acknowledges feedback from a collective made up of various
RIR technical folk; however, heartfelt thanks goes to Anand Buddhdev
of the RIPE-NCC and Robert Loomans of APNIC for being both alpha and
beta testers and providing valuable feedback.
Author's Address
Terry Manderson
ICANN
Email: terry.manderson@icann.org
Manderson Informational [Page 10]
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