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Obsoleted by:5730 DRAFT STANDARD
Network Working Group                                      S. HollenbeckRequest for Comments: 4930                                VeriSign, Inc.Obsoletes:3730                                                 May 2007Category: Standards TrackExtensible Provisioning Protocol (EPP)Status of This Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The IETF Trust (2007).Abstract   This document describes an application layer client-server protocol   for the provisioning and management of objects stored in a shared   central repository.  Specified in XML, the protocol defines generic   object management operations and an extensible framework that maps   protocol operations to objects.  This document includes a protocol   specification, an object mapping template, and an XML media type   registration.  This document obsoletesRFC 3730.Hollenbeck                  Standards Track                     [Page 1]

RFC 4930                          EPP                           May 2007Table of Contents1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .31.1.  Conventions Used in This Document  . . . . . . . . . . . .32.  Protocol Description . . . . . . . . . . . . . . . . . . . . .42.1.  Transport Mapping Considerations . . . . . . . . . . . . .72.2.  Protocol Identification  . . . . . . . . . . . . . . . . .82.3.  Hello Format . . . . . . . . . . . . . . . . . . . . . . .82.4.  Greeting Format  . . . . . . . . . . . . . . . . . . . . .82.5.  Command Format . . . . . . . . . . . . . . . . . . . . . .122.6.  Response Format  . . . . . . . . . . . . . . . . . . . . .132.7.  Protocol Extension Framework . . . . . . . . . . . . . . .182.7.1.  Protocol Extension . . . . . . . . . . . . . . . . . .182.7.2.  Object Extension . . . . . . . . . . . . . . . . . . .182.7.3.  Command-Response Extension . . . . . . . . . . . . . .192.8.  Object Identification  . . . . . . . . . . . . . . . . . .202.9.  Protocol Commands  . . . . . . . . . . . . . . . . . . . .212.9.1.  Session Management Commands  . . . . . . . . . . . . .212.9.1.1.  EPP <login> Command  . . . . . . . . . . . . . . .212.9.1.2.  EPP <logout> Command . . . . . . . . . . . . . . .242.9.2.  Query Commands . . . . . . . . . . . . . . . . . . . .252.9.2.1.  EPP <check> Command  . . . . . . . . . . . . . . .252.9.2.2.  EPP <info> Command . . . . . . . . . . . . . . . .272.9.2.3.  EPP <poll> Command . . . . . . . . . . . . . . . .282.9.2.4.  EPP <transfer> Query Command . . . . . . . . . . .322.9.3.  Object Transform Commands  . . . . . . . . . . . . . .342.9.3.1.  EPP <create> Command . . . . . . . . . . . . . . .342.9.3.2.  EPP <delete> Command . . . . . . . . . . . . . . .362.9.3.3.  EPP <renew> Command  . . . . . . . . . . . . . . .372.9.3.4.  EPP <transfer> Command . . . . . . . . . . . . . .392.9.3.5.  EPP <update> Command . . . . . . . . . . . . . . .413.  Result Codes . . . . . . . . . . . . . . . . . . . . . . . . .424.  Formal Syntax  . . . . . . . . . . . . . . . . . . . . . . . .484.1.  Base Schema  . . . . . . . . . . . . . . . . . . . . . . .484.2.  Shared Structure Schema  . . . . . . . . . . . . . . . . .585.  Internationalization Considerations  . . . . . . . . . . . . .606.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .617.  Security Considerations  . . . . . . . . . . . . . . . . . . .628.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .639.  References . . . . . . . . . . . . . . . . . . . . . . . . . .639.1.  Normative References . . . . . . . . . . . . . . . . . . .639.2.  Informative References . . . . . . . . . . . . . . . . . .64Appendix A.  Object Mapping Template . . . . . . . . . . . . . . .66Appendix B.  Media Type Registration: application/epp+xml  . . . .68Appendix C.  Changes fromRFC 3730 . . . . . . . . . . . . . . . .69Hollenbeck                  Standards Track                     [Page 2]

RFC 4930                          EPP                           May 20071.  Introduction   This document describes specifications for the Extensible   Provisioning Protocol (EPP) version 1.0, an XML text protocol that   permits multiple service providers to perform object provisioning   operations using a shared central object repository.  EPP is   specified using the Extensible Markup Language (XML) 1.0 as described   in [W3C.REC-xml-20040204] and XML Schema notation as described in   [W3C.REC-xmlschema-1-20041028] and [W3C.REC-xmlschema-2-20041028].   EPP meets and exceeds the requirements for a generic registry   registrar protocol as described in [RFC3375].  This document   obsoletesRFC 3730 [RFC3730].   EPP content is identified by MIME media type application/epp+xml.   Registration information for this media type is included in an   appendix to this document.   EPP is intended for use in diverse operating environments where   transport and security requirements vary greatly.  It is unlikely   that a single transport or security specification will meet the needs   of all anticipated operators, so EPP was designed for use in a   layered protocol environment.  Bindings to specific transport and   security protocols are outside the scope of this specification.   The original motivation for this protocol was to provide a standard   Internet domain name registration protocol for use between domain   name registrars and domain name registries.  This protocol provides a   means of interaction between a registrar's applications and registry   applications.  It is expected that this protocol will have additional   uses beyond domain name registration.   XML is case sensitive.  Unless stated otherwise, XML specifications   and examples provided in this document MUST be interpreted in the   character case presented to develop a conforming implementation.1.1.  Conventions Used in This Document   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 [RFC2119].   In examples, "C:" represents lines sent by a protocol client and "S:"   represents lines returned by a protocol server.  Indentation and   white space in examples are provided only to illustrate element   relationships and are not a REQUIRED feature of this protocol.Hollenbeck                  Standards Track                     [Page 3]

RFC 4930                          EPP                           May 20072.  Protocol Description   EPP is a stateful XML protocol that can be layered over multiple   transport protocols.  Protected using lower-layer security protocols,   clients exchange identification, authentication, and option   information, and then engage in a series of client-initiated command-   response exchanges.  All EPP commands are atomic (there is no partial   success or partial failure) and designed so that they can be made   idempotent (executing a command more than once has the same net   effect on system state as successfully executing the command once).   EPP provides four basic service elements: service discovery,   commands, responses, and an extension framework that supports   definition of managed objects and the relationship of protocol   requests and responses to those objects.   An EPP server MUST respond to client-initiated communication (which   can be either a lower-layer connection request or an EPP service   discovery message) by returning a greeting to a client.  A server   MUST promptly respond to each EPP command with a coordinated response   that describes the results of processing the command.  The following   server state machine diagram illustrates the message exchange process   in detail:Hollenbeck                  Standards Track                     [Page 4]

RFC 4930                          EPP                           May 2007              |              V      +-----------------+                  +-----------------+      |   Waiting for   |     Connected    |     Prepare     |      |      Client     |----------------->|     Greeting    |      +-----------------+    or <hello>    +-----------------+         ^                                           |         | Close Connection                     Send |         |     or Idle                      Greeting |      +-----------------+                            V      |       End       |     Timeout      +-----------------+      |     Session     |<-----------------|   Waiting for   |      +-----------------+                  |      Client     |         ^    ^    ^        Send +-------->|  Authentication |         |    |    |    Response |         +-----------------+         |    |    |     +--------------+            |         |    |    |     | Prepare Fail |            | <login>         |    |    +-----|   Response   |            | Received         |    |    Send  +--------------+            V         |    |    2501          ^         +-----------------+         |    |   Response       |         |   Processing    |         |    |                  +---------|     <login>     |         |    |                  Auth Fail +-----------------+         |    |       Timeout                         |         |    +-------------------------------+       | Auth OK         |                                    |       V         |   +-----------------+  <hello>  +-----------------+         |   |     Prepare     |<----------|   Waiting for   |         |   |     Greeting    |---------->|   Command or    |         |   +-----------------+   Send    |     <hello>     |         | Send x5xx             Greeting  +-----------------+         | Response  +-----------------+  Send    ^  |         +-----------|     Prepare     | Response |  | Command                     |     Response    |----------+  | Received                     +-----------------+             V                                ^          +-----------------+                        Command |          |   Processing    |                      Processed +----------|     Command     |                                           +-----------------+   Figure 1: EPP Server State Machine   EPP commands fall into three categories: session management commands,   query commands, and object transform commands.  Session management   commands are used to establish and end persistent sessions with an   EPP server.  Query commands are used to perform read-only object   information retrieval operations.  Transform commands are used to   perform read-write object management operations.Hollenbeck                  Standards Track                     [Page 5]

RFC 4930                          EPP                           May 2007   Commands are processed by a server in the order they are received   from a client.  Though an immediate response confirming receipt and   processing of the command is produced by the server, the protocol   includes features that allow for offline review of transform commands   before the requested action is actually completed.  In such   situations, the response from the server MUST clearly note that the   command has been received and processed, but the requested action is   pending.  The state of the corresponding object MUST clearly reflect   processing of the pending action.  The server MUST also notify the   client when offline processing of the action has been completed.   Object mappings SHOULD describe standard formats for notices that   describe completion of offline processing.   EPP uses XML namespaces to provide an extensible object management   framework and to identify schemas required for XML instance parsing   and validation.  These namespaces and schema definitions are used to   identify both the base protocol schema and the schemas for managed   objects.  The XML namespace prefixes used in examples (such as the   string "foo" in "xmlns:foo") are solely for illustrative purposes.  A   conforming implementation MUST NOT require the use of these or any   other specific namespace prefixes.   All XML instances SHOULD begin with an <?xml?> declaration to   identify the version of XML that is being used, optionally identify   use of the character encoding used, and optionally provide a hint to   an XML parser that an external schema file is needed to validate the   XML instance.  Conformant XML parsers recognize both UTF-8 (defined   inRFC 3629 [RFC3629]) and UTF-16 (defined inRFC 2781 [RFC2781]);   perRFC 2277 [RFC2277] UTF-8 is the RECOMMENDED character encoding   for use with EPP.   Character encodings other than UTF-8 and UTF-16 are allowed by XML.   UTF-8 is the default encoding assumed by XML in the absence of an   "encoding" attribute or a byte order mark (BOM); thus, the "encoding"   attribute in the XML declaration is OPTIONAL if UTF-8 encoding is   used.  EPP clients and servers MUST accept a UTF-8 BOM if present,   though emitting a UTF-8 BOM is NOT RECOMMENDED.   Example XML declarations:   <?xml version="1.0" encoding="UTF-8" standalone="no"?>   <?xml version="1.0" standalone="no"?>   <?xml version="1.0" encoding="UTF-8"?>   <?xml version="1.0"?>Hollenbeck                  Standards Track                     [Page 6]

RFC 4930                          EPP                           May 20072.1.  Transport Mapping Considerations   As described previously, EPP can be layered over multiple transport   protocols.  There are, however, a common set of considerations that   MUST be addressed by any transport mapping defined for EPP.  These   include:   -  The transport mapping MUST preserve command order.   -  The transport mapping MUST address the relationship between      sessions and the client-server connection concept.   -  The transport mapping MUST preserve the stateful nature of the      protocol.   -  The transport mapping MUST frame data units.   -  The transport mapping MUST be onto a transport such as TCP      [RFC0793] or Stream Control Transmission Protocol (SCTP) [RFC2960]      that provides congestion avoidance that followsRFC 2914      [RFC2914], or if it maps onto a protocol such as SMTP [RFC2821] or      Blocks Extensible Exchange Protocol (BEEP) [RFC3080], then the      performance issues need to take into account issues of overload,      server availability, and so forth.   -  The transport mapping MUST ensure reliability.   -  The transport mapping MUST explicitly allow or prohibit      pipelining.   Pipelining, also known as command streaming, is when a client sends   multiple commands to a server without waiting for each corresponding   response.  After sending the commands, the client waits for the   responses to arrive in the order corresponding to the completed   commands.  Performance gains can sometimes be realized with   pipelining, especially with high-latency transports, but there are   additional considerations associated with defining a transport   mapping that supports pipelining:   -  Commands MUST be processed independent of each other.   -  Depending on the transport, pipelining MAY be possible in the form      of sending a complete session in a well-defined "batch".Hollenbeck                  Standards Track                     [Page 7]

RFC 4930                          EPP                           May 2007   -  The transport mapping MUST describe how an error in processing a      command affects continued operation of the session.   A transport mapping MUST explain how all of these requirements are   met given the transport protocol being used to exchange data.2.2.  Protocol Identification   All EPP XML instances MUST begin with an <epp> element.  This element   identifies the start of an EPP protocol element and the namespace   used within the protocol.  The <epp> start element and the associated   </epp> ending element MUST be applied to all structures sent by both   clients and servers.   Example "start" and "end" EPP elements:   <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   </epp>2.3.  Hello Format   EPP MAY be carried over both connection-oriented and connection-less   transport protocols.  An EPP client MAY request a <greeting> from an   EPP server at any time between a successful <login> command and a   <logout> command by sending a <hello> to a server.  Use of this   element is essential in a connection-less environment where a server   cannot return a <greeting> in response to a client-initiated   connection.  An EPP <hello> MUST be an empty element with no child   elements.   Example <hello>:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <hello/>   C:</epp>2.4.  Greeting Format   An EPP server responds to a successful connection and <hello> element   by returning a <greeting> element to the client.  An EPP greeting   contains the following elements:   -  An <svID> element that contains the name of the server.Hollenbeck                  Standards Track                     [Page 8]

RFC 4930                          EPP                           May 2007   -  An <svDate> element that contains the server's current date and      time in UTC.   -  An <svcMenu> element that identifies the services supported by the      server, including:      -  One or more <version> elements that identify the protocol         versions supported by the server.      -  One or more <lang> elements that contain the identifiers of the         text response languages known by the server.  Language         identifiers MUST be structured as documented in [RFC3066].      -  One or more <objURI> elements that contain namespace URIs         representing the objects that the server is capable of         managing.  A server MAY limit object management privileges on a         per-client basis.      -  An OPTIONAL <svcExtension> element that contains one or more         <extURI> elements that contain namespace URIs representing         object extensions supported by the server.      -  A <dcp> (data collection policy) element that contains child         elements used to describe the server's privacy policy for data         collection and management.  Policy implications usually extend         beyond the client-server relationship.  Both clients and         servers can have relationships with other entities that need to         know the server operator's data collection policy to make         informed provisioning decisions.  Policy information MUST be         disclosed to provisioning entities, though the method of         disclosing policy data outside of direct protocol interaction         is beyond the scope of this specification.  Child elements         include the following:         -  An <access> element that describes the access provided by            the server to the client on behalf of the originating data            source.  The <access> element MUST contain one of the            following child elements:            -  <all/>: Access is given to all identified data.            -  <none/>: No access is provided to identified data.            -  <null/>: Data is not persistent, so no access is               possible.Hollenbeck                  Standards Track                     [Page 9]

RFC 4930                          EPP                           May 2007            -  <personal/>: Access is given to identified data relating               to individuals and organizational entities.            -  <personalAndOther/>: Access is given to identified data               relating to individuals, organizational entities, and               other data of a non-personal nature.            -  <other/>: Access is given to other identified data of a               non-personal nature.         -  One or more <statement> elements that describe data            collection purposes, data recipients, and data retention.            Each <statement> element MUST contain a <purpose> element, a            <recipient> element, and a <retention> element.  The            <purpose> element MUST contain one or more of the following            child elements that describe the purposes for which data is            collected:            -  <admin/>: Administrative purposes.  Information can be               used for administrative and technical support of the               provisioning system.            -  <contact/>: Contact for marketing purposes.  Information               can be used to contact individuals, through a               communications channel other than the protocol, for the               promotion of a product or service.            -  <prov/>: Object provisioning purposes.  Information can               be used to identify objects and inter-object               relationships.            -  <other/>: Other purposes.  Information may be used in               other ways not captured by the above definitions.         -  The <recipient> element MUST contain one or more of the            following child elements that describes the recipients of            collected data:            -  <other/>: Other entities following unknown practices.            -  <ours>: Server operator and/or entities acting as agents               or entities for whom the server operator is acting as an               agent.  An agent in this instance is defined as a third               party that processes data only on behalf of the service               provider for the completion of the stated purposes.  The               <ours> element contains an OPTIONAL <recDesc> element               that can be used to describe the recipient.Hollenbeck                  Standards Track                    [Page 10]

RFC 4930                          EPP                           May 2007            -  <public/>: Public forums.            -  <same/>: Other entities following server practices.            -  <unrelated/>: Unrelated third parties.         -  The <retention> element MUST contain one of the following            child elements that describes data retention practices:            -  <business/>: Data persists per business practices.            -  <indefinite/>: Data persists indefinitely.            -  <legal/>: Data persists per legal requirements.            -  <none/>: Data is not persistent and is not retained for               more than a brief period of time necessary to make use of               it during the course of a single online interaction.            -  <stated/>: Data persists to meet the stated purpose.         -  An OPTIONAL <expiry> element that describes the lifetime of            the policy.  The <expiry> element MUST contain one of the            following child elements:            -  <absolute/>: The policy is valid from the current date               and time until it expires on the specified date and time.            -  <relative/>: The policy is valid from the current date               and time until the end of the specified duration.   Data collection policy elements are based on work described in the   World Wide Web Consortium's Platform for Privacy Preferences   [W3C.REC-P3P-20020416] specification.Hollenbeck                  Standards Track                    [Page 11]

RFC 4930                          EPP                           May 2007   Example greeting:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <greeting>   S:    <svID>Example EPP server epp.example.com</svID>   S:    <svDate>2000-06-08T22:00:00.0Z</svDate>   S:    <svcMenu>   S:      <version>1.0</version>   S:      <lang>en</lang>   S:      <lang>fr</lang>   S:      <objURI>urn:ietf:params:xml:ns:obj1</objURI>   S:      <objURI>urn:ietf:params:xml:ns:obj2</objURI>   S:      <objURI>urn:ietf:params:xml:ns:obj3</objURI>   S:      <svcExtension>   S:        <extURI>http://custom/obj1ext-1.0</extURI>   S:      </svcExtension>   S:    </svcMenu>   S:    <dcp>   S:      <access><all/></access>   S:      <statement>   S:        <purpose><admin/><prov/></purpose>   S:        <recipient><ours/><public/></recipient>   S:        <retention><stated/></retention>   S:      </statement>   S:    </dcp>   S:  </greeting>   S:</epp>2.5.  Command Format   An EPP client interacts with an EPP server by sending a command to   the server and receiving a response from the server.  In addition to   the standard EPP elements, an EPP command contains the following   elements:   -  A command element whose tag corresponds to one of the valid EPP      commands described in this document.  The command element MAY      contain either protocol-specified or object-specified child      elements.   -  An OPTIONAL <extension> element that MAY be used for server-      defined command extensions.Hollenbeck                  Standards Track                    [Page 12]

RFC 4930                          EPP                           May 2007   -  An OPTIONAL <clTRID> (client transaction identifier) element that      MAY be used to uniquely identify the command to the client.      Clients are responsible for maintaining their own transaction      identifier space to ensure uniqueness.   Example command with object-specified child elements:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <info>   C:      <obj:info xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <obj:name>example</obj:name>   C:      </obj:info>   C:    </info>   C:    <clTRID>ABC-12345</clTRID>   C:  </command>   C:</epp>2.6.  Response Format   An EPP server responds to a client command by returning a response to   the client.  EPP commands are atomic, so a command will either   succeed completely or fail completely.  Success and failure results   MUST NOT be mixed.  In addition to the standard EPP elements, an EPP   response contains the following elements:   -  One or more <result> elements that document the success or failure      of command execution.  If the command was processed successfully,      only one <result> element MUST be returned.  If the command was      not processed successfully, multiple <result> elements MAY be      returned to document failure conditions.  Each <result> element      contains the following attribute and child elements:      -  A "code" attribute whose value is a four-digit, decimal number         that describes the success or failure of the command.      -  A <msg> element containing a human-readable description of the         response code.  The language of the response is identified via         an OPTIONAL "lang" attribute.  If not specified, the default         attribute value MUST be "en" (English).      -  Zero or more OPTIONAL <value> elements that identify a client-         provided element (including XML tag and value) or other         information that caused a server error condition.Hollenbeck                  Standards Track                    [Page 13]

RFC 4930                          EPP                           May 2007      -  Zero or more OPTIONAL <extValue> elements that can be used to         provide additional error diagnostic information, including:         -  A <value> element that identifies a client-provided element            (including XML tag and value) that caused a server error            condition.         -  A <reason> element containing a human-readable message that            describes the reason for the error.  The language of the            response is identified via an OPTIONAL "lang" attribute.  If            not specified, the default attribute value MUST be "en"            (English).   -  An OPTIONAL <msgQ> element that describes messages queued for      client retrieval.  A <msgQ> element MUST NOT be present if there      are no messages queued for client retrieval.  A <msgQ> element MAY      be present in responses to EPP commands other than the <poll>      command if messages are queued for retrieval.  A <msgQ> element      MUST be present in responses to the EPP <poll> command if messages      are queued for retrieval.  The <msgQ> element contains the      following attributes:      -  A "count" attribute that describes the number of messages that         exist in the queue.      -  An "id" attribute used to uniquely identify the message at the         head of the queue.      The <msgQ> element contains the following OPTIONAL child elements      that MUST be returned in response to a <poll> request command and      MUST NOT be returned in response to any other command, including a      <poll> acknowledgement:      -  A <qDate> element that contains the date and time that the         message was enqueued.      -  A <msg> element containing a human-readable message.  The         language of the response is identified via an OPTIONAL "lang"         attribute.  If not specified, the default attribute value MUST         be "en" (English).  This element MAY contain XML content for         formatting purposes, but the XML content is not specified by         the protocol and will thus not be processed for validity.   -  An OPTIONAL <resData> (response data) element that contains child      elements specific to the command and associated object.Hollenbeck                  Standards Track                    [Page 14]

RFC 4930                          EPP                           May 2007   -  An OPTIONAL <extension> element that MAY be used for server-      defined response extensions.   -  A <trID> (transaction identifier) element containing the      transaction identifier assigned by the server to the command for      which the response is being returned.  The transaction identifier      is formed using the <clTRID> associated with the command if      supplied by the client and a <svTRID> (server transaction      identifier) that is assigned by and unique to the server.   Transaction identifiers provide command-response synchronization   integrity.  They SHOULD be logged, retained, and protected to ensure   that both the client and the server have consistent temporal and   state management records.   Example response without <value> or <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg lang="en">Command completed successfully</msg>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>Hollenbeck                  Standards Track                    [Page 15]

RFC 4930                          EPP                           May 2007   Example response with <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:creData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:name>example</obj:name>   S:      </obj:creData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>Hollenbeck                  Standards Track                    [Page 16]

RFC 4930                          EPP                           May 2007   Example response with error value elements:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="2004">   S:      <msg>Parameter value range error</msg>   S:      <value xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:elem1>2525</obj:elem1>   S:      </value>   S:    </result>   S:    <result code="2005">   S:      <msg>Parameter value syntax error</msg>   S:      <value xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:elem2>ex(ample</obj:elem2>   S:      </value>   S:      <extValue>   S:        <value xmlns:obj="urn:ietf:params:xml:ns:obj">   S:          <obj:elem3>abc.ex(ample</obj:elem3>   S:        </value>   S:        <reason>Invalid character found.</reason>   S:      </extValue>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   Example response with notice of waiting server messages:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <msgQ count="5"/>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>Hollenbeck                  Standards Track                    [Page 17]

RFC 4930                          EPP                           May 2007   Command success or failure MUST NOT be assumed if no response is   returned or if a returned response is malformed.  Protocol   idempotency ensures the safety of retrying a command in cases of   response delivery failure.2.7.  Protocol Extension Framework   EPP provides an extension framework that allows features to be added   at the protocol, object, and command-response levels.2.7.1.  Protocol Extension   The EPP extension framework allows for definition of new protocol   elements identified using XML namespace notation with a reference to   an XML schema that defines the namespace.  The <epp> element that   identifies the beginning of a protocol instance includes multiple   child element choices, one of which is an <extension> element whose   children define the extension.  For example, a protocol extension   element would be described in generic terms as follows:   C:<epp>   C:  <extension>   C:    <!-- One or more extension elements. -->   C:    <ext:foo xmlns:ext="urn:ietf:params:xml:ns:ext">   C:      <!-- One or more extension child elements. -->   C:    </ext:foo>   C:  </extension>   C:</epp>   This document does not define mappings for specific extensions.   Extension specifications MUST be described in separate documents that   define the objects and operations subject to the extension.2.7.2.  Object Extension   EPP provides an extensible object management framework that defines   the syntax and semantics of protocol operations applied to a managed   object.  This framework pushes the definition of each protocol   operation into the context of a specific object, providing the   ability to add mappings for new objects without having to modify the   base protocol.   Protocol elements that contain data specific to objects are   identified using XML namespace notation with a reference to an XML   schema that defines the namespace.  The schema for EPP supports use   of dynamic object schemas on a per-command and per-response basis.   For example, the start of an object-specific command element would be   described in generic terms as follows:Hollenbeck                  Standards Track                    [Page 18]

RFC 4930                          EPP                           May 2007   C:<EPPCommandName>   C:  <object:command xmlns:object="urn:ietf:params:xml:ns:object">   C:    <!-- One or more object-specific command elements. -->   C:  </object:command>   C:</EPPCommandName>   An object-specific response element would be described similarly:   S:<resData>   S:  <object:resData xmlns:object="urn:ietf:params:xml:ns:object">   S:    <!-- One or more object-specific response elements. -->   S:  </object:resData>   S:</resData>   This document does not define mappings for specific objects.  The   mapping of EPP to an object MUST be described in separate documents   that specifically address each command and response in the context of   the object.  A suggested object mapping outline is included as an   appendix to this document.2.7.3.  Command-Response Extension   EPP provides a facility for protocol command and response extensions.   Protocol commands and responses MAY be extended by an <extension>   element that contains additional elements whose syntax and semantics   are not explicitly defined by EPP or an EPP object mapping.  This   element is OPTIONAL.  Extensions are typically defined by agreement   between client and server and MAY be used to extend EPP for unique   operational needs.  A server-extended command element would be   described in generic terms as follows:   C:<command>   C:  <!-- EPPCommandName can be "create", "update", etc. -->   C:  <EPPCommandName>   C:    <object:command xmlns:object="urn:ietf:params:xml:ns:object">   C:      <!-- One or more object-specific command elements. -->   C:    </object:command>   C:  </EPPCommandName>   C:  <extension>   C:    <!-- One or more server-defined elements. -->   C:  </extension>   C:</command>   An server-extended response element would be described similarly:Hollenbeck                  Standards Track                    [Page 19]

RFC 4930                          EPP                           May 2007   S:<response>   S:  <result code="1000">   S:    <msg lang="en">Command completed successfully</msg>   S:  </result>   S:  <extension>   S:    <!-- One or more server-defined elements. -->   S:  </extension>   S:  <trID>   S:    <clTRID>ABC-12345</clTRID>   S:    <svTRID>54321-XYZ</svTRID>   S:  </trID>   S:</response>   This document does not define any specific server extensions.  The   mapping of server extensions to EPP MUST be described in separate   documents that specifically address extended commands and responses   in the server's operational context.2.8.  Object Identification   Some objects, such as name servers and contacts, can have utility in   multiple repositories.  However, maintaining disjoint copies of   object information in multiple repositories can lead to   inconsistencies that have adverse consequences for the Internet.  For   example, changing a name server name in one repository, but not in a   second repository that refers to the server for domain name   delegation, can produce unexpected DNS query results.   Globally unique identifiers can help facilitate object information   sharing between repositories.  A globally unique identifier MUST be   assigned to every object when the object is created; the identifier   MUST be returned to the client as part of any request to retrieve the   detailed attributes of an object.  Specific identifier values are a   matter of repository policy, but they SHOULD be constructed according   to the following algorithm:   a.  Divide the provisioning repository world into a number of object       repository classes.   b.  Each repository within a class is assigned an identifier that is       maintained by IANA.   c.  Each repository is responsible for assigning a unique local       identifier for each object within the repository.   d.  The globally unique identifier is a concatenation of the local       identifier, followed by a hyphen ("-", ASCII value 0x002D),       followed by the repository identifier.Hollenbeck                  Standards Track                    [Page 20]

RFC 4930                          EPP                           May 20072.9.  Protocol Commands   EPP provides commands to manage sessions, retrieve object   information, and perform transformation operations on objects.  All   EPP commands are atomic and designed so that they can be made   idempotent, either succeeding completely or failing completely and   producing predictable results in case of repeated executions.  This   section describes each EPP command, including examples with   representative server responses.2.9.1.  Session Management Commands   EPP provides two commands for session management: <login> to   establish a session with a server, and <logout> to end a session with   a server.  The <login> command establishes an ongoing server session   that preserves client identity and authorization information during   the duration of the session.2.9.1.1.  EPP <login> Command   The EPP <login> command is used to establish a session with an EPP   server in response to a greeting issued by the server.  A <login>   command MUST be sent to a server before any other EPP command to   establish an ongoing session.  A server operator MAY limit the number   of failed login attempts N, 1 <= N <= infinity, after which a login   failure results in the connection to the server (if a connection   exists) being closed.   A client identifier and initial password MUST be created on the   server before a client can successfully complete a <login> command.   The client identifier and initial password MUST be delivered to the   client using an out-of-band method that protects the identifier and   password from inadvertent disclosure.   In addition to the standard EPP command elements, the <login> command   contains the following child elements:   -  A <clID> element that contains the client identifier assigned to      the client by the server.   -  A <pw> element that contains the client's plain text password.      The value of this element is case sensitive.   -  An OPTIONAL <newPW> element that contains a new plain text      password to be assigned to the client for use with subsequent      <login> commands.  The value of this element is case sensitive.Hollenbeck                  Standards Track                    [Page 21]

RFC 4930                          EPP                           May 2007   -  An <options> element that contains the following child elements:      -  A <version> element that contains the protocol version to be         used for the command or ongoing server session.      -  A <lang> element that contains the text response language to be         used for the command or ongoing server session commands.      The values of the <version> and <lang> elements MUST exactly match      one of the values presented in the EPP greeting.   -  A <svcs> element that contains one or more <objURI> elements that      contain namespace URIs representing the objects to be managed      during the session.  The <svcs> element MAY contain an OPTIONAL      <svcExtension> element that contains one or more <extURI> elements      that identify object extensions to be used during the session.   The PLAIN Simple Authentication and Security Layer (SASL) mechanism   presented in [RFC2595] describes a format for providing a user   identifier, an authorization identifier, and a password as part of a   single plain text string.  The EPP authentication mechanism is   similar, though EPP does not require a session-level authorization   identifier and the user identifier and password are separated into   distinct XML elements.  Additional identification and authorization   schemes MUST be provided at other protocol layers to provide more   robust security services.Hollenbeck                  Standards Track                    [Page 22]

RFC 4930                          EPP                           May 2007   Example <login> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <login>   C:      <clID>ClientX</clID>   C:      <pw>foo-BAR2</pw>   C:      <newPW>bar-FOO2</newPW>   C:      <options>   C:        <version>1.0</version>   C:        <lang>en</lang>   C:      </options>   C:      <svcs>   C:        <objURI>urn:ietf:params:xml:ns:obj1</objURI>   C:        <objURI>urn:ietf:params:xml:ns:obj2</objURI>   C:        <objURI>urn:ietf:params:xml:ns:obj3</objURI>   C:        <svcExtension>   C:          <extURI>http://custom/obj1ext-1.0</extURI>   C:        </svcExtension>   C:      </svcs>   C:    </login>   C:    <clTRID>ABC-12345</clTRID>   C:  </command>   C:</epp>   When a <login> command has been processed successfully, a server MUST   respond with an EPP response with no <resData> element.  If   successful, the server will respond by creating and maintaining a new   session that SHOULD be terminated by a future <logout> command.   Example <login> response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>Hollenbeck                  Standards Track                    [Page 23]

RFC 4930                          EPP                           May 2007   The EPP <login> command is used to establish a session with an EPP   server.  A <login> command MUST be rejected if received within the   bounds of an existing session.  This action MUST be open to all   authorized clients.2.9.1.2.  EPP <logout> Command   The EPP <logout> command is used to end a session with an EPP server.   The <logout> command MUST be represented as an empty element with no   child elements.   A server MAY end a session due to client inactivity or excessive   client session longevity.  The parameters for determining excessive   client inactivity or session longevity are a matter of server policy   and are not specified by this protocol.   Transport mappings MUST explicitly describe any connection-oriented   processing that takes place after processing a <logout> command and   ending a session.   Example <logout> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <logout/>   C:    <clTRID>ABC-12345</clTRID>   C:  </command>   C:</epp>   When a <logout> command has been processed successfully, a server   MUST respond with an EPP response with no <resData> element.  If   successful, the server MUST also end the current session.   Example <logout> response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1500">   S:      <msg>Command completed successfully; ending session</msg>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>Hollenbeck                  Standards Track                    [Page 24]

RFC 4930                          EPP                           May 2007   The EPP <logout> command is used to end a session with an EPP server.   A <logout> command MUST be rejected if the command has not been   preceded by a successful <login> command.  This action MUST be open   to all authorized clients.2.9.2.  Query Commands2.9.2.1.  EPP <check> Command   The EPP <check> command is used to determine if an object can be   provisioned within a repository.  It provides a hint that allows a   client to anticipate the success or failure of provisioning an object   using the <create> command as object provisioning requirements are   ultimately a matter of server policy.   The elements needed to identify an object are object-specific, so the   child elements of the <check> command are specified using the EPP   extension framework.  In addition to the standard EPP command   elements, the <check> command contains the following child elements:   -  An object-specific <obj:check> element that identifies the objects      to be queried.  Multiple objects of the same type MAY be queried      within a single <check> command.   Example <check> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <check>   C:      <obj:check xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <obj:name>example1</obj:name>   C:        <obj:name>example2</obj:name>   C:        <obj:name>example3</obj:name>   C:      </obj:check>   C:    </check>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When a <check> command has been processed successfully, a server MUST   respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific, though the EPP <resData>   element MUST contain a child <obj:chkData> element that contains one   or more <obj:cd> (check data) elements.  Each <obj:cd> element   contains the following child elements:Hollenbeck                  Standards Track                    [Page 25]

RFC 4930                          EPP                           May 2007   -  An object-specific element that identifies the queried object.      This element MUST contain an "avail" attribute whose value      indicates object availability (can it be provisioned or not) at      the moment the <check> command was completed.  A value of "1" or      "true" means that the object can be provisioned.  A value of "0"      or "false" means that the object cannot be provisioned.   -  An OPTIONAL <obj:reason> element that MAY be provided when an      object cannot be provisioned.  If present, this element contains      server-specific text to help explain why the object cannot be      provisioned.  This text MUST be represented in the response      language previously negotiated with the client; an OPTIONAL "lang"      attribute MAY be present to identify the language if the      negotiated value is something other than the default value of "en"      (English).   Example <check> response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:chkData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:cd>   S:          <obj:name avail="1">example1</obj:name>   S:        </obj:cd>   S:        <obj:cd>   S:          <obj:name avail="0">example2</obj:name>   S:          <obj:reason>In use</obj:reason>   S:        </obj:cd>   S:        <obj:cd>   S:          <obj:name avail="1">example3</obj:name>   S:        </obj:cd>   S:      </obj:chkData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <check> command is used to determine if an object can be   provisioned within a repository.  This action MUST be open to all   authorized clients.Hollenbeck                  Standards Track                    [Page 26]

RFC 4930                          EPP                           May 20072.9.2.2.  EPP <info> Command   The EPP <info> command is used to retrieve information associated   with an existing object.  The elements needed to identify an object   and the type of information associated with an object are both   object-specific, so the child elements of the <info> command are   specified using the EPP extension framework.  In addition to the   standard EPP command elements, the <info> command contains the   following child elements:   -  An object-specific <obj:info> element that identifies the object      to be queried.   Example <info> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <info>   C:      <obj:info xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:info>   C:    </info>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When an <info> command has been processed successfully, a server MUST   respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace and the Repository   Object IDentifier (ROID) that was assigned to the object when the   object was created.  Other child elements of the <resData> element   are object-specific.Hollenbeck                  Standards Track                    [Page 27]

RFC 4930                          EPP                           May 2007   Example <info> response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:infData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:roid>EXAMPLE1-REP</obj:roid>   S:        <!-- Object-specific elements. -->   S:      </obj:infData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <info> command is used to retrieve information associated   with an existing object.  This action SHOULD be limited to authorized   clients; restricting this action to the sponsoring client is   RECOMMENDED.2.9.2.3.  EPP <poll> Command   The EPP <poll> command is used to discover and retrieve service   messages queued by a server for individual clients.  If the message   queue is not empty, a successful response to a <poll> command MUST   return the first message from the message queue.  Each response   returned from the server includes a server-unique message identifier   that MUST be provided to acknowledge receipt of the message, and a   counter that indicates the number of messages in the queue.  After a   message has been received by the client, the client MUST respond to   the message with an explicit acknowledgement to confirm that the   message has been received.  A server MUST dequeue the message and   decrement the queue counter after receiving acknowledgement from the   client, making the next message in the queue (if any) available for   retrieval.   Servers can occasionally perform actions on objects that are not in   direct response to a client request, or an action taken by one client   can indirectly involve a second client.  Examples of such actions   include deletion upon expiration, automatic renewal upon expiration,   and transfer coordination; other types of service information MAY be   defined as a matter of server policy.  Service messages SHOULD beHollenbeck                  Standards Track                    [Page 28]

RFC 4930                          EPP                           May 2007   created for passive clients affected by an action on an object.   Service messages MAY also be created for active clients that request   an action on an object, though such messages MUST NOT replace the   normal protocol response to the request.  For example, <transfer>   actions SHOULD be reported to the client that has the authority to   approve or reject a transfer request.  Other methods of server-client   action notification, such as offline reporting, are also possible and   are beyond the scope of this specification.   Message queues can consume server resources if clients do not   retrieve and acknowledge messages on a regular basis.  Servers MAY   implement other mechanisms to dequeue and deliver messages if queue   maintenance needs exceed server resource consumption limits.  Server   operators SHOULD consider time-sensitivity and resource management   factors when selecting a delivery method for service information   because some message types can be reasonably delivered using non-   protocol methods that require fewer server resources.   Some of the information returned in response to a <poll> command can   be object-specific, so some child elements of the <poll> response MAY   be specified using the EPP extension framework.  The <poll> command   MUST be represented as an empty element with no child elements.  An   "op" attribute with value "req" is REQUIRED to retrieve the first   message from the server message queue.  An "op" attribute (with value   "ack") and a "msgID" attribute (whose value corresponds to the value   of the "id" attribute copied from the <msg> element in the message   being acknowledged) are REQUIRED to acknowledge receipt of a message.   Example <poll> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <poll op="req"/>   C:    <clTRID>ABC-12345</clTRID>   C:  </command>   C:</epp>   The returned result code notes that a message has been dequeued and   returned in response to a <poll> command.Hollenbeck                  Standards Track                    [Page 29]

RFC 4930                          EPP                           May 2007   Example <poll> response with object-specific information:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1301">   S:      <msg>Command completed successfully; ack to dequeue</msg>   S:    </result>   S:    <msgQ count="5">   S:      <qDate>2000-06-08T22:00:00.0Z</qDate>   S:      <msg>Transfer requested.</msg>   S:    </msgQ>   S:    <resData>   S:      <obj:trnData   S:       xmlns:obj="urn:ietf:params:xml:ns:obj-1.0">   S:        <obj:name>example.com</obj:name>   S:        <obj:trStatus>pending</obj:trStatus>   S:        <obj:reID>ClientX</obj:reID>   S:        <obj:reDate>2000-06-08T22:00:00.0Z</obj:reDate>   S:        <obj:acID>ClientY</obj:acID>   S:        <obj:acDate>2000-06-13T22:00:00.0Z</obj:acDate>   S:        <obj:exDate>2002-09-08T22:00:00.0Z</obj:exDate>   S:      </obj:trnData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   A client MUST acknowledge each response to dequeue the message and   make subsequent messages available for retrieval.   Example <poll> acknowledgement command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <poll op="ack" msgID="12345"/>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   A <poll> acknowledgement response notes the ID of the message that   has been acknowledged and the number of messages remaining in the   queue.Hollenbeck                  Standards Track                    [Page 30]

RFC 4930                          EPP                           May 2007   Example <poll> acknowledgement response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <msgQ count="4"/>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   Service messages can also be returned without object information.   Example <poll> response with mixed message content and without   object-specific information:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1301">   S:      <msg>Command completed successfully; ack to dequeue</msg>   S:    </result>   S:    <msgQ count="4">   S:      <qDate>2000-06-08T22:10:00.0Z</qDate>   S:      <msg lang="en">Credit balance low.   S:        <limit>100</limit><bal>5</bal>   S:      </msg>   S:    </msgQ>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The returned result code and message is used to note an empty server   message queue.Hollenbeck                  Standards Track                    [Page 31]

RFC 4930                          EPP                           May 2007   Example <poll> response to note an empty message queue:      S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>      S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">      S:  <response>      S:    <result code="1300">      S:      <msg>Command completed successfully; no messages</msg>      S:    </result>      S:    <trID>      S:      <clTRID>ABC-12346</clTRID>      S:      <svTRID>54321-XYZ</svTRID>      S:    </trID>      S:  </response>      S:</epp>   The EPP <poll> command is used to discover and retrieve client   service messages from a server.  This action SHOULD be limited to   authorized clients; queuing service messages and limiting queue   access on a per-client basis is RECOMMENDED.2.9.2.4.  EPP <transfer> Query Command   The EPP <transfer> command provides a query operation that allows a   client to determine real-time status of pending and completed   transfer requests.  The elements needed to identify an object that is   the subject of a transfer request are object-specific, so the child   elements of the <transfer> query command are specified using the EPP   extension framework.  In addition to the standard EPP command   elements, the <transfer> command contains an "op" attribute with   value "query", and the following child elements:   -  An object-specific <obj:transfer> element that identifies the      object whose transfer status is requested.   Transfer status is typically considered sensitive information by the   clients involved in the operation.  Object mappings MUST provide   features to restrict transfer queries to authorized clients, such as   by requiring authorization information as part of the request.Hollenbeck                  Standards Track                    [Page 32]

RFC 4930                          EPP                           May 2007   Example <transfer> query command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <transfer op="query">   C:      <obj:transfer xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:transfer>   C:    </transfer>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When a <transfer> query command has been processed successfully, a   server MUST respond with an EPP <resData> element that MUST contain a   child element that identifies the object namespace.  The child   elements of the <resData> element are object-specific, but they MUST   include elements that identify the object, the status of the   transfer, the identifier of the client that requested the transfer,   the date and time that the request was made, the identifier of the   client that is authorized to act on the request, the date and time by   which an action is expected, and an OPTIONAL date and time noting   changes in the object's validity period (if applicable) that occur as   a result of the transfer.Hollenbeck                  Standards Track                    [Page 33]

RFC 4930                          EPP                           May 2007   Example <transfer> query response:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:trnData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:name>example</obj:name>   S:        <obj:trStatus>pending</obj:trStatus>   S:        <obj:reID>ClientX</obj:reID>   S:        <obj:reDate>2000-06-08T22:00:00.0Z</obj:reDate>   S:        <obj:acID>ClientY</obj:acID>   S:        <obj:acDate>2000-06-13T22:00:00.0Z</obj:acDate>   S:        <obj:exDate>2002-09-08T22:00:00.0Z</obj:exDate>   S:      </obj:trnData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <transfer> command provides a query operation that allows a   client to determine real-time status of pending and completed   transfer requests.  This action SHOULD be limited to authorized   clients; restricting queries to the requesting and responding clients   is RECOMMENDED.  Object transfer MAY be unavailable or limited by   object-specific policies.2.9.3.  Object Transform Commands   EPP provides five commands to transform objects: <create> to create   an instance of an object with a server, <delete> to remove an   instance of an object from a server, <renew> to extend the validity   period of an object, <transfer> to manage changes in client   sponsorship of an object, and <update> to change information   associated with an object.2.9.3.1.  EPP <create> Command   The EPP <create> command is used to create an instance of an object.   An object can be created for an indefinite period of time, or an   object can be created for a specific validity period.  The EPP   mapping for an object MUST describe the status of an object withHollenbeck                  Standards Track                    [Page 34]

RFC 4930                          EPP                           May 2007   respect to time, to include expected client and server behavior if a   validity period is used.   The elements needed to identify an object and associated attributes   are object-specific, so the child elements of the <create> command   are specified using the EPP extension framework.  In addition to the   standard EPP command elements, the <create> command contains the   following child elements:   -  An object-specific <obj:create> element that identifies the object      to be created and the elements that are required to create the      object.   Example <create> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <create>   C:      <obj:create xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:create>   C:    </create>   C:    <clTRID>ABC-12345</clTRID>   C:  </command>   C:</epp>   When a <create> command has been processed successfully, a server MAY   respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific.Hollenbeck                  Standards Track                    [Page 35]

RFC 4930                          EPP                           May 2007   Example <create> response with <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:creData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <!-- Object-specific elements. -->   S:      </obj:creData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12345</clTRID>   S:      <svTRID>54321-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <create> command is used to create an instance of an object.   This action SHOULD be limited to authorized clients and MAY be   restricted on a per-client basis.2.9.3.2.  EPP <delete> Command   The EPP <delete> command is used to remove an instance of an existing   object.  The elements needed to identify an object are object-   specific, so the child elements of the <delete> command are specified   using the EPP extension framework.  In addition to the standard EPP   command elements, the <delete> command contains the following child   elements:   -  An object-specific <obj:delete> element that identifies the object      to be deleted.Hollenbeck                  Standards Track                    [Page 36]

RFC 4930                          EPP                           May 2007   Example <delete> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <delete>   C:      <obj:delete xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:delete>   C:    </delete>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When a <delete> command has been processed successfully, a server MAY   respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific.   Example <delete> response without <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <delete> command is used to remove an instance of an existing   object.  This action SHOULD be limited to authorized clients;   restricting this action to the sponsoring client is RECOMMENDED.2.9.3.3.  EPP <renew> Command   The EPP <renew> command is used to extend the validity period of an   existing object.  The elements needed to identify and extend the   validity period of an object are object-specific, so the child   elements of the <renew> command are specified using the EPP extension   framework.  In addition to the standard EPP command elements, the   <renew> command contains the following child elements:Hollenbeck                  Standards Track                    [Page 37]

RFC 4930                          EPP                           May 2007   -  An object-specific <obj:renew> element that identifies the object      to be renewed and the elements that are required to extend the      validity period of the object.   Example <renew> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <renew>   C:      <obj:renew xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:renew>   C:    </renew>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When a <renew> command has been processed successfully, a server MAY   respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific.   Example <renew> response with <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <resData>   S:      <obj:renData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <!-- Object-specific elements. -->   S:      </obj:renData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <renew> command is used to extend the validity period of an   existing object.  This action SHOULD be limited to authorized   clients; restricting this action to the sponsoring client is   RECOMMENDED.  Object renewal MAY be unavailable or limited by object-   specific policies.Hollenbeck                  Standards Track                    [Page 38]

RFC 4930                          EPP                           May 20072.9.3.4.  EPP <transfer> Command   The EPP <transfer> command is used to manage changes in client   sponsorship of an existing object.  Clients can initiate a transfer   request, cancel a transfer request, approve a transfer request, and   reject a transfer request using the "op" command attribute.   A client who wishes to assume sponsorship of a known object from   another client uses the <transfer> command with the value of the "op"   attribute set to "request".  Once a transfer has been requested, the   same client can cancel the request using a <transfer> command with   the value of the "op" attribute set to "cancel".  A request to cancel   the transfer MUST be sent to the server before the current sponsoring   client either approves or rejects the transfer request and before the   server automatically processes the request due to responding client   inactivity.   Once a transfer request has been received by the server, the server   MUST notify the current sponsoring client of the requested transfer   either by queuing a service message for retrieval via the <poll>   command or by using an out-of-band mechanism to inform the client of   the request.  The current status of a pending <transfer> command for   any object can be found using the <transfer> query command.  Transfer   service messages MUST include the object-specific elements specified   for <transfer> command responses.   The current sponsoring client MAY explicitly approve or reject the   transfer request.  The client can approve the request using a   <transfer> command with the value of the "op" attribute set to   "approve".  The client can reject the request using a <transfer>   command with the value of the "op" attribute set to "reject".   A server MAY automatically approve or reject all transfer requests   that are not explicitly approved or rejected by the current   sponsoring client within a fixed amount of time.  The amount of time   to wait for explicit action and the default server behavior are local   matters not specified by EPP, but they SHOULD be documented in a   server-specific profile document that describes default server   behavior for client information.   Objects eligible for transfer MUST have associated authorization   information that MUST be provided to complete a <transfer> command.   The type of authorization information required is object-specific;   passwords or more complex mechanisms based on public key cryptography   are typical.Hollenbeck                  Standards Track                    [Page 39]

RFC 4930                          EPP                           May 2007   The elements needed to identify and complete the transfer of an   object are object-specific, so the child elements of the <transfer>   command are specified using the EPP extension framework.  In addition   to the standard EPP command elements, the <transfer> command contains   the following child elements:   -  An object-specific <obj:transfer> element that identifies the      object to be transferred and the elements that are required to      process the transfer command.   Example <transfer> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <transfer op="request">   C:      <obj:transfer xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:transfer>   C:    </transfer>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When a <transfer> command has been processed successfully, a server   MUST respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific, but they MUST include   elements that identify the object, the status of the transfer, the   identifier of the client that requested the transfer, the date and   time that the request was made, the identifier of the client that is   authorized to act on the request, the date and time by which an   action is expected, and an OPTIONAL date and time noting changes in   the object's validity period (if applicable) that occur as a result   of the transfer.Hollenbeck                  Standards Track                    [Page 40]

RFC 4930                          EPP                           May 2007   Example <transfer> response with <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1001">   S:      <msg>Command completed successfully; action pending</msg>   S:    </result>   S:    <resData>   S:      <obj:trnData xmlns:obj="urn:ietf:params:xml:ns:obj">   S:        <obj:name>example</obj:name>   S:        <obj:trStatus>pending</obj:trStatus>   S:        <obj:reID>ClientX</obj:reID>   S:        <obj:reDate>2000-06-08T22:00:00.0Z</obj:reDate>   S:        <obj:acID>ClientY</obj:acID>   S:        <obj:acDate>2000-06-13T22:00:00.0Z</obj:acDate>   S:        <obj:exDate>2002-09-08T22:00:00.0Z</obj:exDate>   S:      </obj:trnData>   S:    </resData>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <transfer> command is used to manage changes in client   sponsorship of an existing object.  This action SHOULD be limited to   authorized clients; restricting <transfer> requests to a client other   than the current sponsoring client, <transfer> approval requests to   the current sponsoring client, and <transfer> cancellation requests   to the original requesting client is RECOMMENDED.  Object transfer   MAY be unavailable or limited by object-specific policies.2.9.3.5.  EPP <update> Command   The EPP <update> command is used to change information associated   with an existing object.  The elements needed to identify and modify   an object are object-specific, so the child elements of the <update>   command are specified using the EPP extension framework.  In addition   to the standard EPP command elements, the <update> command contains   the following child elements:   -  An object-specific <obj:update> element that identifies the object      to be updated and the elements that are required to modify the      object.  Object-specific elements MUST identify values to be      added, values to be removed, or values to be changed.Hollenbeck                  Standards Track                    [Page 41]

RFC 4930                          EPP                           May 2007   Example <update> command:   C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   C:  <command>   C:    <update>   C:      <obj:update xmlns:obj="urn:ietf:params:xml:ns:obj">   C:        <!-- Object-specific elements. -->   C:      </obj:update>   C:    </update>   C:    <clTRID>ABC-12346</clTRID>   C:  </command>   C:</epp>   When an <update> command has been processed successfully, a server   MAY respond with an EPP <resData> element that MUST contain a child   element that identifies the object namespace.  The child elements of   the <resData> element are object-specific.   Example <update> response without <resData>:   S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>   S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">   S:  <response>   S:    <result code="1000">   S:      <msg>Command completed successfully</msg>   S:    </result>   S:    <trID>   S:      <clTRID>ABC-12346</clTRID>   S:      <svTRID>54322-XYZ</svTRID>   S:    </trID>   S:  </response>   S:</epp>   The EPP <update> command is used to change information associated   with an existing object.  This action SHOULD be limited to authorized   clients; restricting this action to the sponsoring client is   RECOMMENDED.3.  Result Codes   EPP result codes are based on the theory of reply codes described insection 4.2.1 of [RFC2821].  EPP uses four decimal digits to describe   the success or failure of each EPP command.  Each of the digits of   the reply have special significance.Hollenbeck                  Standards Track                    [Page 42]

RFC 4930                          EPP                           May 2007   The first digit denotes command success or failure.  The second digit   denotes the response category, such as command syntax or security.   The third and fourth digits provide explicit response detail within   each response category.   There are two values for the first digit of the reply code:   1yzz    Positive completion reply.  The command was accepted and           processed by the system without error.   2yzz    Negative completion reply.  The command was not accepted, and           the requested action did not occur.   The second digit groups responses into one of six specific   categories:   x0zz    Protocol Syntax   x1zz    Implementation-specific Rules   x2zz    Security   x3zz    Data Management   x4zz    Server System   x5zz    Connection Management   The third and fourth digits provide response detail within the   categories defined by the first and second digits.  Specific result   codes are listed in the table below.   Every EPP response MUST include a result code and a human-readable   description of the result code.  The language used to represent the   description MAY be identified using an instance of the "lang"   attribute within the <msg> element.  If not specified, the default   language is English, identified as "en".  A description of the   structure of valid values for the "lang" attribute is described in   [RFC3066].   Response text MAY be translated into other languages, though the   translation MUST preserve the meaning of the code as described here.   Response code values MUST NOT be changed when translating text.   Response text in the table below is enclosed in quotes to clearly   mark the beginning and ending of each response string.  Quotes MUST   NOT be used to delimit these strings when returning response text via   the protocol.   Successful command completion responses:Hollenbeck                  Standards Track                    [Page 43]

RFC 4930                          EPP                           May 2007   Code    Response text in English   ____    ________________________   1000    "Command completed successfully"           This is the usual response code for a successfully completed           command that is not addressed by any other 1xxx-series           response code.   1001    "Command completed successfully; action pending"           This response code MUST be returned when responding to a           command that requires offline activity before the requested           action can be completed.  SeeSection 2 for a description of           other processing requirements.   1300    "Command completed successfully; no messages"           This response code MUST be returned when responding to a           <poll> request command and the server message queue is empty.   1301    "Command completed successfully; ack to dequeue"           This response code MUST be returned when responding to a           <poll> request command and a message has been retrieved from           the server message queue.   1500    "Command completed successfully; ending session"           This response code MUST be returned when responding to a           successful <logout> command.   Command error responses:   Code    Response text in English   ____    ________________________   2000    "Unknown command"           This response code MUST be returned when a server receives a           command element that is not defined by EPP.   2001    "Command syntax error"           This response code MUST be returned when a server receives an           improperly formed command element.   2002    "Command use error"           This response code MUST be returned when a server receives a           properly formed command element, but the command cannot be           executed due to a sequencing or context error.  For example,           a <logout> command cannot be executed without having first           completed a <login> command.Hollenbeck                  Standards Track                    [Page 44]

RFC 4930                          EPP                           May 2007   2003    "Required parameter missing"           This response code MUST be returned when a server receives a           command for which a required parameter value has not been           provided.   2004    "Parameter value range error"           This response code MUST be returned when a server receives a           command parameter whose value is outside the range of values           specified by the protocol.  The error value SHOULD be           returned via a <value> element in the EPP response.   2005    "Parameter value syntax error"           This response code MUST be returned when a server receives a           command containing a parameter whose value is improperly           formed.  The error value SHOULD be returned via a <value>           element in the EPP response.   2100    "Unimplemented protocol version"           This response code MUST be returned when a server receives a           command element specifying a protocol version that is not           implemented by the server.   2101    "Unimplemented command"           This response code MUST be returned when a server receives a           valid EPP command element that is not implemented by the           server.  For example, a <transfer> command can be           unimplemented for certain object types.   2102    "Unimplemented option"           This response code MUST be returned when a server receives a           valid EPP command element that contains a protocol option           that is not implemented by the server.   2103    "Unimplemented extension"           This response code MUST be returned when a server receives a           valid EPP command element that contains a protocol command           extension that is not implemented by the server.   2104    "Billing failure"           This response code MUST be returned when a server attempts to           execute a billable operation and the command cannot be           completed due to a client billing failure.   2105    "Object is not eligible for renewal"           This response code MUST be returned when a client attempts to           <renew> an object that is not eligible for renewal in           accordance with server policy.Hollenbeck                  Standards Track                    [Page 45]

RFC 4930                          EPP                           May 2007   2106    "Object is not eligible for transfer"           This response code MUST be returned when a client attempts to           <transfer> an object that is not eligible for transfer in           accordance with server policy.   2200    "Authentication error"           This response code MUST be returned when a server notes an           error when validating client credentials.   2201    "Authorization error"           This response code MUST be returned when a server notes a           client authorization error when executing a command.  This           error is used to note that a client lacks privileges to           execute the requested command.   2202    "Invalid authorization information"           This response code MUST be returned when a server receives           invalid command authorization information required to confirm           authorization to execute a command.  This error is used to           note that a client has the privileges required to execute the           requested command, but the authorization information provided           by the client does not match the authorization information           archived by the server.   2300    "Object pending transfer"           This response code MUST be returned when a server receives a           command to transfer of an object that is pending transfer due           to an earlier transfer request.   2301    "Object not pending transfer"           This response code MUST be returned when a server receives a           command to confirm, reject, or cancel the transfer an object           when no command has been made to transfer the object.   2302    "Object exists"           This response code MUST be returned when a server receives a           command to create an object that already exists in the           repository.   2303    "Object does not exist"           This response code MUST be returned when a server receives a           command to query or transform an object that does not exist           in the repository.Hollenbeck                  Standards Track                    [Page 46]

RFC 4930                          EPP                           May 2007   2304    "Object status prohibits operation"           This response code MUST be returned when a server receives a           command to transform an object that cannot be completed due           to server policy or business practices.  For example, a           server can disallow <transfer> commands under terms and           conditions that are matters of local policy, or the server           might have received a <delete> command for an object whose           status prohibits deletion.   2305    "Object association prohibits operation"           This response code MUST be returned when a server receives a           command to transform an object that cannot be completed due           to dependencies on other objects that are associated with the           target object.  For example, a server can disallow <delete>           commands while an object has active associations with other           objects.   2306    "Parameter value policy error"           This response code MUST be returned when a server receives a           command containing a parameter value that is syntactically           valid, but semantically invalid due to local policy.  For           example, the server can support a subset of a range of valid           protocol parameter values.  The error value SHOULD be           returned via a <value> element in the EPP response.   2307    "Unimplemented object service"           This response code MUST be returned when a server receives a           command to operate on an object service that is not supported           by the server.   2308    "Data management policy violation"           This response code MUST be returned when a server receives a           command whose execution results in a violation of server data           management policies.  For example, removing all attribute           values or object associations from an object might be a           violation of a server's data management policies.   2400    "Command failed"           This response code MUST be returned when a server is unable           to execute a command due to an internal server error that is           not related to the protocol.  The failure can be transient.           The server MUST keep any ongoing session active.Hollenbeck                  Standards Track                    [Page 47]

RFC 4930                          EPP                           May 2007   2500    "Command failed; server closing connection"           This response code MUST be returned when a server receives a           command that cannot be completed due to an internal server           error that is not related to the protocol.  The failure is           not transient and will cause other commands to fail as well.           The server MUST end the active session and close the existing           connection.   2501    "Authentication error; server closing connection"           This response code MUST be returned when a server notes an           error when validating client credentials and a server-defined           limit on the number of allowable failures has been exceeded.           The server MUST close the existing connection.   2502    "Session limit exceeded; server closing connection"           This response code MUST be returned when a server receives a           <login> command, and the command cannot be completed because           the client has exceeded a system-defined limit on the number           of sessions that the client can establish.  It might be           possible to establish a session by ending existing unused           sessions and closing inactive connections.4.  Formal Syntax   EPP is specified in XML Schema notation.  The formal syntax presented   here is a complete schema representation of EPP suitable for   automated validation of EPP XML instances.   Two schemas are presented here.  The first schema is the base EPP   schema.  The second schema defines elements and structures that can   be used by both the base EPP schema and object mapping schemas.  The   BEGIN and END tags are not part of the schema; they are used to note   the beginning and ending of the schema for URI registration purposes.4.1.  Base Schema   BEGIN   <?xml version="1.0" encoding="UTF-8"?>   <schema targetNamespace="urn:ietf:params:xml:ns:epp-1.0"           xmlns:epp="urn:ietf:params:xml:ns:epp-1.0"           xmlns:eppcom="urn:ietf:params:xml:ns:eppcom-1.0"           xmlns="http://www.w3.org/2001/XMLSchema"           elementFormDefault="qualified">   <!--   Import common element types.   -->Hollenbeck                  Standards Track                    [Page 48]

RFC 4930                          EPP                           May 2007     <import namespace="urn:ietf:params:xml:ns:eppcom-1.0"/>     <annotation>       <documentation>         Extensible Provisioning Protocol v1.0 schema.       </documentation>     </annotation>   <!--   Every EPP XML instance must begin with this element.   -->     <element name="epp" type="epp:eppType"/>   <!--   An EPP XML instance must contain a greeting, hello, command,   response, or extension.   -->     <complexType name="eppType">       <choice>         <element name="greeting" type="epp:greetingType"/>         <element name="hello"/>         <element name="command" type="epp:commandType"/>         <element name="response" type="epp:responseType"/>         <element name="extension" type="epp:extAnyType"/>       </choice>     </complexType>   <!--   A greeting is sent by a server in response to a client connection   or <hello>.   -->     <complexType name="greetingType">       <sequence>         <element name="svID" type="epp:sIDType"/>         <element name="svDate" type="dateTime"/>         <element name="svcMenu" type="epp:svcMenuType"/>         <element name="dcp" type="epp:dcpType"/>       </sequence>     </complexType>   <!--   Server IDs are strings with minimum and maximum length restrictions.   -->     <simpleType name="sIDType">       <restriction base="normalizedString">         <minLength value="3"/>         <maxLength value="64"/>       </restriction>Hollenbeck                  Standards Track                    [Page 49]

RFC 4930                          EPP                           May 2007     </simpleType>   <!--   A server greeting identifies available object services.   -->     <complexType name="svcMenuType">       <sequence>         <element name="version" type="epp:versionType"          maxOccurs="unbounded"/>         <element name="lang" type="language"          maxOccurs="unbounded"/>         <element name="objURI" type="anyURI"          maxOccurs="unbounded"/>         <element name="svcExtension" type="epp:extURIType"          minOccurs="0"/>       </sequence>     </complexType>   <!--   Data Collection Policy types.   -->     <complexType name="dcpType">       <sequence>         <element name="access" type="epp:dcpAccessType"/>         <element name="statement" type="epp:dcpStatementType"          maxOccurs="unbounded"/>         <element name="expiry" type="epp:dcpExpiryType"          minOccurs="0"/>       </sequence>     </complexType>     <complexType name="dcpAccessType">       <choice>         <element name="all"/>         <element name="none"/>         <element name="null"/>         <element name="other"/>         <element name="personal"/>         <element name="personalAndOther"/>       </choice>     </complexType>     <complexType name="dcpStatementType">       <sequence>         <element name="purpose" type="epp:dcpPurposeType"/>         <element name="recipient" type="epp:dcpRecipientType"/>         <element name="retention" type="epp:dcpRetentionType"/>       </sequence>Hollenbeck                  Standards Track                    [Page 50]

RFC 4930                          EPP                           May 2007     </complexType>     <complexType name="dcpPurposeType">       <sequence>         <element name="admin"          minOccurs="0"/>         <element name="contact"          minOccurs="0"/>         <element name="other"          minOccurs="0"/>         <element name="prov"          minOccurs="0"/>       </sequence>     </complexType>     <complexType name="dcpRecipientType">       <sequence>         <element name="other"          minOccurs="0"/>         <element name="ours" type="epp:dcpOursType"          minOccurs="0" maxOccurs="unbounded"/>         <element name="public"          minOccurs="0"/>         <element name="same"          minOccurs="0"/>         <element name="unrelated"          minOccurs="0"/>       </sequence>     </complexType>     <complexType name="dcpOursType">       <sequence>         <element name="recDesc" type="epp:dcpRecDescType"          minOccurs="0"/>       </sequence>     </complexType>     <simpleType name="dcpRecDescType">       <restriction base="token">         <minLength value="1"/>         <maxLength value="255"/>       </restriction>     </simpleType>     <complexType name="dcpRetentionType">       <choice>         <element name="business"/>         <element name="indefinite"/>Hollenbeck                  Standards Track                    [Page 51]

RFC 4930                          EPP                           May 2007         <element name="legal"/>         <element name="none"/>         <element name="stated"/>       </choice>     </complexType>     <complexType name="dcpExpiryType">       <choice>         <element name="absolute" type="dateTime"/>         <element name="relative" type="duration"/>       </choice>     </complexType>   <!--   Extension framework types.   -->     <complexType name="extAnyType">       <sequence>         <any namespace="##other"          maxOccurs="unbounded"/>       </sequence>     </complexType>     <complexType name="extURIType">       <sequence>         <element name="extURI" type="anyURI"          maxOccurs="unbounded"/>       </sequence>     </complexType>   <!--   An EPP version number is a dotted pair of decimal numbers.   -->     <simpleType name="versionType">       <restriction base="token">         <pattern value="[1-9]+\.[0-9]+"/>         <enumeration value="1.0"/>       </restriction>     </simpleType>   <!--   Command types.   -->     <complexType name="commandType">       <sequence>         <choice>           <element name="check" type="epp:readWriteType"/>           <element name="create" type="epp:readWriteType"/>Hollenbeck                  Standards Track                    [Page 52]

RFC 4930                          EPP                           May 2007           <element name="delete" type="epp:readWriteType"/>           <element name="info" type="epp:readWriteType"/>           <element name="login" type="epp:loginType"/>           <element name="logout"/>           <element name="poll" type="epp:pollType"/>           <element name="renew" type="epp:readWriteType"/>           <element name="transfer" type="epp:transferType"/>           <element name="update" type="epp:readWriteType"/>         </choice>         <element name="extension" type="epp:extAnyType"          minOccurs="0"/>         <element name="clTRID" type="epp:trIDStringType"          minOccurs="0"/>       </sequence>     </complexType>   <!--   The <login> command.   -->     <complexType name="loginType">       <sequence>         <element name="clID" type="eppcom:clIDType"/>         <element name="pw" type="epp:pwType"/>         <element name="newPW" type="epp:pwType"          minOccurs="0"/>         <element name="options" type="epp:credsOptionsType"/>         <element name="svcs" type="epp:loginSvcType"/>       </sequence>     </complexType>     <complexType name="credsOptionsType">       <sequence>         <element name="version" type="epp:versionType"/>         <element name="lang" type="language"/>       </sequence>     </complexType>     <simpleType name="pwType">       <restriction base="token">         <minLength value="6"/>         <maxLength value="16"/>       </restriction>     </simpleType>     <complexType name="loginSvcType">       <sequence>         <element name="objURI" type="anyURI"          maxOccurs="unbounded"/>Hollenbeck                  Standards Track                    [Page 53]

RFC 4930                          EPP                           May 2007         <element name="svcExtension" type="epp:extURIType"          minOccurs="0"/>       </sequence>     </complexType>   <!--   The <poll> command.   -->     <complexType name="pollType">       <attribute name="op" type="epp:pollOpType"        use="required"/>       <attribute name="msgID" type="token"/>     </complexType>     <simpleType name="pollOpType">       <restriction base="token">         <enumeration value="ack"/>         <enumeration value="req"/>       </restriction>     </simpleType>   <!--   The <transfer> command.  This is object-specific, and uses attributes   to identify the requested operation.   -->     <complexType name="transferType">       <sequence>         <any namespace="##other"/>       </sequence>       <attribute name="op" type="epp:transferOpType"        use="required"/>     </complexType>     <simpleType name="transferOpType">       <restriction base="token">         <enumeration value="approve"/>         <enumeration value="cancel"/>         <enumeration value="query"/>         <enumeration value="reject"/>         <enumeration value="request"/>       </restriction>     </simpleType>   <!--   All other object-centric commands.  EPP doesn't specify the syntax or   semantics of object-centric command elements.  The elements MUST be   described in detail in another schema specific to the object.   -->Hollenbeck                  Standards Track                    [Page 54]

RFC 4930                          EPP                           May 2007     <complexType name="readWriteType">       <sequence>         <any namespace="##other"/>       </sequence>     </complexType>     <complexType name="trIDType">       <sequence>         <element name="clTRID" type="epp:trIDStringType"          minOccurs="0"/>         <element name="svTRID" type="epp:trIDStringType"/>       </sequence>     </complexType>     <simpleType name="trIDStringType">       <restriction base="token">         <minLength value="3"/>         <maxLength value="64"/>       </restriction>     </simpleType>   <!--   Response types.   -->     <complexType name="responseType">       <sequence>         <element name="result" type="epp:resultType"          maxOccurs="unbounded"/>         <element name="msgQ" type="epp:msgQType"          minOccurs="0"/>         <element name="resData" type="epp:extAnyType"          minOccurs="0"/>         <element name="extension" type="epp:extAnyType"          minOccurs="0"/>         <element name="trID" type="epp:trIDType"/>       </sequence>     </complexType>     <complexType name="resultType">       <sequence>         <element name="msg" type="epp:msgType"/>         <choice minOccurs="0" maxOccurs="unbounded">           <element name="value" type="epp:errValueType"/>           <element name="extValue" type="epp:extErrValueType"/>         </choice>       </sequence>       <attribute name="code" type="epp:resultCodeType"        use="required"/>Hollenbeck                  Standards Track                    [Page 55]

RFC 4930                          EPP                           May 2007     </complexType>     <complexType name="errValueType" mixed="true">       <sequence>         <any namespace="##any" processContents="skip"/>       </sequence>       <anyAttribute namespace="##any" processContents="skip"/>     </complexType>     <complexType name="extErrValueType">       <sequence>         <element name="value" type="epp:errValueType"/>         <element name="reason" type="epp:msgType"/>       </sequence>     </complexType>     <complexType name="msgQType">       <sequence>         <element name="qDate" type="dateTime"          minOccurs="0"/>         <element name="msg" type="epp:mixedMsgType"          minOccurs="0"/>       </sequence>       <attribute name="count" type="unsignedLong"        use="required"/>       <attribute name="id" type="eppcom:minTokenType"        use="required"/>     </complexType>     <complexType name="mixedMsgType" mixed="true">       <sequence>         <any processContents="skip"          minOccurs="0" maxOccurs="unbounded"/>       </sequence>       <attribute name="lang" type="language"        default="en"/>     </complexType>   <!--   Human-readable text may be expressed in languages other than English.   -->     <complexType name="msgType">       <simpleContent>         <extension base="normalizedString">           <attribute name="lang" type="language"            default="en"/>         </extension>       </simpleContent>Hollenbeck                  Standards Track                    [Page 56]

RFC 4930                          EPP                           May 2007     </complexType>   <!--   EPP result codes.   -->     <simpleType name="resultCodeType">       <restriction base="unsignedShort">         <enumeration value="1000"/>         <enumeration value="1001"/>         <enumeration value="1300"/>         <enumeration value="1301"/>         <enumeration value="1500"/>         <enumeration value="2000"/>         <enumeration value="2001"/>         <enumeration value="2002"/>         <enumeration value="2003"/>         <enumeration value="2004"/>         <enumeration value="2005"/>         <enumeration value="2100"/>         <enumeration value="2101"/>         <enumeration value="2102"/>         <enumeration value="2103"/>         <enumeration value="2104"/>         <enumeration value="2105"/>         <enumeration value="2106"/>         <enumeration value="2200"/>         <enumeration value="2201"/>         <enumeration value="2202"/>         <enumeration value="2300"/>         <enumeration value="2301"/>         <enumeration value="2302"/>         <enumeration value="2303"/>         <enumeration value="2304"/>         <enumeration value="2305"/>         <enumeration value="2306"/>         <enumeration value="2307"/>         <enumeration value="2308"/>         <enumeration value="2400"/>         <enumeration value="2500"/>         <enumeration value="2501"/>         <enumeration value="2502"/>       </restriction>     </simpleType>   <!--   End of schema.   -->   </schema>Hollenbeck                  Standards Track                    [Page 57]

RFC 4930                          EPP                           May 2007   END4.2.  Shared Structure Schema   BEGIN   <?xml version="1.0" encoding="UTF-8"?>   <schema targetNamespace="urn:ietf:params:xml:ns:eppcom-1.0"           xmlns:eppcom="urn:ietf:params:xml:ns:eppcom-1.0"           xmlns="http://www.w3.org/2001/XMLSchema"           elementFormDefault="qualified">     <annotation>       <documentation>         Extensible Provisioning Protocol v1.0         shared structures schema.       </documentation>     </annotation>   <!--   Object authorization information types.   -->     <complexType name="pwAuthInfoType">       <simpleContent>         <extension base="normalizedString">           <attribute name="roid" type="eppcom:roidType"/>         </extension>       </simpleContent>     </complexType>     <complexType name="extAuthInfoType">       <sequence>         <any namespace="##other"/>       </sequence>     </complexType>   <!--   <check> response types.   -->     <complexType name="reasonType">       <simpleContent>         <extension base="eppcom:reasonBaseType">           <attribute name="lang" type="language"/>         </extension>       </simpleContent>     </complexType>     <simpleType name="reasonBaseType">Hollenbeck                  Standards Track                    [Page 58]

RFC 4930                          EPP                           May 2007       <restriction base="token">         <minLength value="1"/>         <maxLength value="32"/>       </restriction>     </simpleType>   <!--   Abstract client and object identifier type.   -->     <simpleType name="clIDType">       <restriction base="token">         <minLength value="3"/>         <maxLength value="16"/>       </restriction>     </simpleType>   <!--   DNS label type.   -->     <simpleType name="labelType">       <restriction base="token">         <minLength value="1"/>         <maxLength value="255"/>       </restriction>     </simpleType>   <!--   Non-empty token type.   -->     <simpleType name="minTokenType">       <restriction base="token">         <minLength value="1"/>       </restriction>     </simpleType>   <!--   Repository Object IDentifier type.   -->     <simpleType name="roidType">       <restriction base="token">         <pattern value="(\w|_){1,80}-\w{1,8}"/>       </restriction>     </simpleType>   <!--   Transfer status identifiers.   -->     <simpleType name="trStatusType">Hollenbeck                  Standards Track                    [Page 59]

RFC 4930                          EPP                           May 2007       <restriction base="token">         <enumeration value="clientApproved"/>         <enumeration value="clientCancelled"/>         <enumeration value="clientRejected"/>         <enumeration value="pending"/>         <enumeration value="serverApproved"/>         <enumeration value="serverCancelled"/>       </restriction>     </simpleType>   <!--   End of schema.   -->   </schema>   END5.  Internationalization Considerations   EPP is represented in XML, which provides native support for encoding   information using the Unicode character set and its more compact   representations including UTF-8.  Conformant XML processors recognize   both UTF-8 and UTF-16.  Though XML includes provisions to identify   and use other character encodings through use of an "encoding"   attribute in an <?xml?> declaration, use of UTF-8 is RECOMMENDED in   environments where parser encoding support incompatibility exists.   EPP includes a provision for returning a human-readable message with   every result code.  This document describes result codes in English,   but the actual text returned with a result MAY be provided in a   language negotiated when a session is established.  Languages other   than English MUST be noted through specification of a "lang"   attribute for each message.  Valid values for the "lang" attribute   and "lang" negotiation elements are described in [RFC3066].   All date-time values presented via EPP MUST be expressed in Universal   Coordinated Time using the Gregorian calendar.  XML Schema allows use   of time zone identifiers to indicate offsets from the zero meridian,   but this option MUST NOT be used with EPP.  The extended date-time   form using upper case "T" and "Z" characters defined in   [W3C.REC-xmlschema-2-20041028] MUST be used to represent date-time   values as XML Schema does not support truncated date-time forms or   lower case "T" and "Z" characters.Hollenbeck                  Standards Track                    [Page 60]

RFC 4930                          EPP                           May 20076.  IANA Considerations   This document uses URNs to describe XML namespaces and XML schemas   conforming to a registry mechanism described in [RFC3688].  Four URI   assignments have been registered by the IANA.   Registration request for the EPP namespace:   URI: urn:ietf:params:xml:ns:epp-1.0   Registrant Contact: See the "Author's Address" section of this   document.   XML: None.  Namespace URIs do not represent an XML specification.   Registration request for the EPP XML schema:   URI: urn:ietf:params:xml:schema:epp-1.0   Registrant Contact: See the "Author's Address" section of this   document.   XML: See the "Base Schema" section of this document.   Registration request for the EPP shared structure namespace:   URI: urn:ietf:params:xml:ns:eppcom-1.0   Registrant Contact: See the "Author's Address" section of this   document.   XML: None.  Namespace URIs do not represent an XML specification.   Registration request for the EPP shared structure XML schema:   URI: urn:ietf:params:xml:schema:eppcom-1.0   Registrant Contact: See the "Author's Address" section of this   document.   XML: See the "Shared Structure Schema" section of this document.Hollenbeck                  Standards Track                    [Page 61]

RFC 4930                          EPP                           May 20077.  Security Considerations   EPP provides only simple client authentication services.  A passive   attack is sufficient to recover client identifiers and passwords,   allowing trivial command forgery.  Protection against most common   attacks and more robust security services MUST be provided by other   protocol layers.  Specifically, EPP instances MUST be protected using   a transport mechanism or application protocol that provides   integrity, confidentiality, and mutual strong client-server   authentication.   EPP uses a variant of the PLAIN SASL mechanism described in [RFC2595]   to provide a simple application-layer authentication service that   augments or supplements authentication and identification services   that might be available at other protocol layers.  Where the PLAIN   SASL mechanism specifies provision of an authorization identifier,   authentication identifier, and password as a single string separated   by ASCII NUL characters, EPP specifies use of a combined   authorization and authentication identifier and a password provided   as distinct XML elements.   Repeated password guessing attempts can be discouraged by limiting   the number of <login> attempts that can be attempted on an open   connection.  A server MAY close an open connection if multiple   <login> attempts are made with either an invalid client identifier,   an invalid password, or both an invalid client identifier and an   invalid password.   EPP uses authentication information associated with objects to   confirm object transfer authority.  Authentication information   exchanged between EPP clients and third-party entities MUST be   exchanged using a facility that provides privacy and integrity   services to protect against unintended disclosure and modification   while in transit.   EPP instances SHOULD be protected using a transport mechanism or   application protocol that provides anti-replay protection.  EPP   provides some protection against replay attacks through command   idempotency and client-initiated transaction identification.   Consecutive command replays will not change the state of an object in   any way.  There is, however, a chance of unintended or malicious   consequence if a command is replayed after intervening commands have   changed the object state and client identifiers are not used to   detect replays.  For example, a replayed <create> command that   follows a <delete> command might succeed without additional   facilities to prevent or detect the replay.Hollenbeck                  Standards Track                    [Page 62]

RFC 4930                          EPP                           May 20078.  Acknowledgements   This document was originally written as an individual submission   Internet-Draft.  The PROVREG working group later adopted it as a   working group document and provided many invaluable comments and   suggested improvements.  The author wishes to acknowledge the efforts   of WG chairs Edward Lewis and Jaap Akkerhuis for their process and   editorial contributions.   Specific suggestions that have been incorporated into this document   were provided by Chris Bason, Eric Brunner-Williams, Jordyn Buchanan,   Roger Castillo Cortazar, Dave Crocker, Ayesha Damaraju, Sheer El-   Showk, Patrik Faltstrom, James Gould, John Immordino, Dan Kohn, Hong   Liu, Klaus Malorny, Dan Manley, Michael Mealling, Patrick Mevzek,   Andrew Newton, Budi Rahardjo, Asbjorn Steira, Rick Wesson, and Jay   Westerdal.9.  References9.1.  Normative References   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and              Languages",BCP 18,RFC 2277, January 1998.   [RFC2914]  Floyd, S., "Congestion Control Principles",BCP 41,RFC 2914, September 2000.   [RFC3066]  Alvestrand, H., "Tags for the Identification of              Languages",RFC 3066, January 2001.   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO              10646", STD 63,RFC 3629, November 2003.   [RFC3688]  Mealling, M., "The IETF XML Registry",BCP 81,RFC 3688,              January 2004.   [W3C.REC-xml-20040204]              Yergeau, F., Maler, E., Sperberg-McQueen, C., Bray, T.,              and J. Paoli, "Extensible Markup Language (XML) 1.0 (Third              Edition)", World Wide Web Consortium FirstEdition REC-xml-              20040204, February 2004,              <http://www.w3.org/TR/2004/REC-xml-20040204>.Hollenbeck                  Standards Track                    [Page 63]

RFC 4930                          EPP                           May 2007   [W3C.REC-xmlschema-1-20041028]              Thompson, H., Maloney, M., Mendelsohn, N., and D. Beech,              "XML Schema Part 1: Structures Second Edition", World Wide              Web Consortium Recommendation REC-xmlschema-1-20041028,              October 2004,              <http://www.w3.org/TR/2004/REC-xmlschema-1-20041028>.   [W3C.REC-xmlschema-2-20041028]              Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes              Second Edition", World Wide Web Consortium              Recommendation REC-xmlschema-2-20041028, October 2004,              <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.9.2.  Informative References   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,RFC 793, September 1981.   [RFC2595]  Newman, C., "Using TLS with IMAP, POP3 and ACAP",RFC 2595, June 1999.   [RFC2781]  Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO              10646",RFC 2781, February 2000.   [RFC2821]  Klensin, J., "Simple Mail Transfer Protocol",RFC 2821,              April 2001.   [RFC2960]  Stewart, R., Xie, Q., Morneault, K., Sharp, C.,              Schwarzbauer, H., Taylor, T., Rytina, I., Kalla, M.,              Zhang, L., and V. Paxson, "Stream Control Transmission              Protocol",RFC 2960, October 2000.   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media              Types",RFC 3023, January 2001.   [RFC3080]  Rose, M., "The Blocks Extensible Exchange Protocol Core",RFC 3080, March 2001.   [RFC3375]  Hollenbeck, S., "Generic Registry-Registrar Protocol              Requirements",RFC 3375, September 2002.   [RFC3730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",RFC 3730, March 2004.Hollenbeck                  Standards Track                    [Page 64]

RFC 4930                          EPP                           May 2007   [W3C.REC-P3P-20020416]              Marchiori, M., "The Platform for Privacy Preferences 1.0              (P3P1.0) Specification", World Wide Web Consortium              Recommendation REC-P3P-20020416, April 2002,              <http://www.w3.org/TR/2002/REC-P3P-20020416>.Hollenbeck                  Standards Track                    [Page 65]

RFC 4930                          EPP                           May 2007Appendix A.  Object Mapping Template   This appendix describes a recommended outline for documenting the EPP   mapping of an object.  Documents that describe EPP object mappings   SHOULD describe the mapping in a format similar to the one used here.   Additional sections are required if the object mapping is written in   Internet-Draft or RFC format.   1. Introduction      Provide an introduction that describes the object and an overview      of the mapping to EPP.   2. Object Attributes      Describe the attributes associated with the object, including      references to syntax specifications as appropriate.  Examples of      object attributes include a name or identifier and dates      associated with modification events.   3. EPP Command Mapping   3.1.  EPP Query Commands   3.1.1.  EPP <check> Command      Describe the object-specific mappings required to implement the      EPP <check> command.  Include both sample commands and sample      responses.   3.1.2.  EPP <info> Command      Describe the object-specific mappings required to implement the      EPP <info> command.  Include both sample commands and sample      responses.   3.1.3.  EPP <poll> Command      Describe the object-specific mappings required to implement the      EPP <poll> command.  Include both sample commands and sample      responses.   3.1.4.  EPP <transfer> Command      Describe the object-specific mappings required to implement the      EPP <transfer> query command.  Include both sample commands and      sample responses.Hollenbeck                  Standards Track                    [Page 66]

RFC 4930                          EPP                           May 2007   3.2.  EPP Transform Commands   3.2.1.  EPP <create> Command      Describe the object-specific mappings required to implement the      EPP <create> command.  Include both sample commands and sample      responses.  Describe the status of the object with respect to      time, including expected client and server behavior if a validity      period is used.   3.2.2.  EPP <delete> Command      Describe the object-specific mappings required to implement the      EPP <delete> command.  Include both sample commands and sample      responses.   3.2.3.  EPP <renew> Command      Describe the object-specific mappings required to implement the      EPP <renew> command.  Include both sample commands and sample      responses.   3.2.4.  EPP <transfer> Command      Describe the object-specific mappings required to implement the      EPP <transfer> command.  Include both sample commands and sample      responses.   3.2.4.  EPP <update> Command      Describe the object-specific mappings required to implement the      EPP <update> command.  Include both sample commands and sample      responses.   4. Formal Syntax      Provide the XML schema for the object mapping.  An XML DTD MUST      NOT be used as DTDs do not provide sufficient support for XML      namespaces and strong data typing.Hollenbeck                  Standards Track                    [Page 67]

RFC 4930                          EPP                           May 2007Appendix B.  Media Type Registration: application/epp+xml   MIME media type name: application   MIME subtype name: epp+xml   Required parameters: none   Optional parameters: Same as the charset parameter of application/xml   as specified in [RFC3023].   Encoding considerations: Same as the encoding considerations of   application/xml as specified in [RFC3023].   Security considerations: This type has all of the security   considerations described in [RFC3023] plus the considerations   specified in the Security Considerations section of this document.   Interoperability considerations: XML has proven to be interoperable   across WWW Distributed Authoring and Versioning (WebDAV) clients and   servers, and for import and export from multiple XML authoring tools.   For maximum interoperability, validating processors are recommended.   Although non-validating processors can be more efficient, they are   not required to handle all features of XML.  For further information,   seeSection 2.9, "Standalone Document Declaration", andSection 5,   "Conformance", of [W3C.REC-xml-20040204].   Published specification: This document.   Applications that use this media type: EPP is device-, platform-, and   vendor-neutral and is supported by multiple service providers.   Additional information: If used, magic numbers, fragment identifiers,   base URIs, and use of the BOM should be as specified in [RFC3023].   Magic number(s): None.   File extension(s): .xml   Macintosh file type code(s): "TEXT"   Person & email address for further information: See the "Author's   Address" section of this document.   Intended usage: COMMON   Author/Change controller: IETFHollenbeck                  Standards Track                    [Page 68]

RFC 4930                          EPP                           May 2007Appendix C.  Changes fromRFC 3730   1.   Minor reformatting as a result of converting I-D source format        from nroff to XML.   2.   Updated the state diagram inSection 2 to note that a <hello>        can be received and processed at any time that a server is        waiting for a command.  The text correctly describes how this        works, but the state diagram was inconsistent with the text.   3.   InSection 2, changed "The specific strings used to associate        URIs and namespaces (such as the string "foo" in "xmlns:foo") in        EPP are illustrative and are not needed for interoperability" to        "The XML namespace prefixes used in examples (such as the string        "foo" in "xmlns:foo") are solely for illustrative purposes.  A        conforming implementation MUST NOT require the use of these or        any other specific namespace prefixes".   4.   Removed the last paragraph fromSection 2 that described an        error in the W3C XML reference specification.  This was        corrected in a later edition.  References in this specification        have been updated to cite the most current version.  Preserved        the last sentence by appending it to the end of the previous        paragraph.   5.   Updated the description of the <value> element inSection 2.6 to        add "or other information" to "a client-provided element        (including XML tag and value)".   6.   Changed text inSection 2.9.2.3 from this:        "Service messages MUST be created for all clients affected by an        action on an object.  For example, <transfer> actions MUST be        reported to both the client that requests an object transfer and        the client that has the authority to approve or reject the        transfer request."        to this:        "Service messages SHOULD be created for passive clients affected        by an action on an object.  Service messages MAY also be created        for active clients that request an action on an object, though        such messages MUST NOT replace the normal protocol response to        the request.  For example, <transfer> actions SHOULD be reported        to the client that has the authority to approve or reject a        transfer request.  Other methods of server-client action        notification, such as offline reporting, are also possible and        are beyond the scope of this specification."Hollenbeck                  Standards Track                    [Page 69]

RFC 4930                          EPP                           May 2007   7.   Changed text inSection 2.9.2.3 from this:        "A <poll> acknowledgement response notes the number of messages        remaining in the queue and the ID of the next message available        for retrieval."        to this:        "A <poll> acknowledgement response notes the ID of the message        that has been acknowledged and the number of messages remaining        in the queue."        Fixed the example to note the correct message ID.  This was done        because the msgID isn't needed to retrieve a message, only to        ack and dequeue it, so it doesn't need to be returned in the        response.  Implementations are known to implement this feature        as updated.   8.   Changed text inSection 2.9.3.4 from this:        "Once a transfer request has been received by the server, the        server MUST notify the current sponsoring client of the        requested transfer by queuing a service message for retrieval        via the <poll> command."        to this:        "Once a transfer request has been received by the server, the        server MUST notify the current sponsoring client of the        requested transfer either by queuing a service message for        retrieval via the <poll> command or by using an out-of-band        mechanism to inform the client of the request."   9.   Updated Security Considerations to note implemented required        practices for authentication and replay protection.   10.  Updated XML references.  Updated reference fromRFC 2279 toRFC3629.   11.  Removed text describing use of the XML Schema schemaLocation        attribute.  This is an optional attribute that doesn't need to        be mandated for use in EPP.   12.  Moved RFCs 2781 and 3375 (Informational RFCs) from the normative        reference section to the informative reference section.Hollenbeck                  Standards Track                    [Page 70]

RFC 4930                          EPP                           May 2007   13.  MovedRFC 3023 from the normative reference section to the        informative reference section.  This reference is used only in        an informative appendix.   14.  Removed references toRFC 3339 and replaced them with references        to the W3C XML Schema specification.Author's Address   Scott Hollenbeck   VeriSign, Inc.   21345 Ridgetop Circle   Dulles, VA  20166-6503   US   EMail: shollenbeck@verisign.comHollenbeck                  Standards Track                    [Page 71]

RFC 4930                          EPP                           May 2007Full Copyright Statement   Copyright (C) The IETF Trust (2007).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and except as set forth therein, the authors   retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the procedures with respect to rights in RFC documents can be   found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at   ietf-ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Hollenbeck                  Standards Track                    [Page 72]

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