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Network Working Group                                             G. ZornRequest for Comments: 2619                                       B. AbobaCategory: Standards Track                                       Microsoft                                                                June 1999RADIUS Authentication Server MIBStatus 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 Internet Society (1999).  All Rights Reserved.Abstract   This memo defines a set of extensions which instrument RADIUS   authentication server functions. These extensions represent a portion   of the Management Information Base (MIB) for use with network   management protocols in the Internet community.  Using these   extensions IP-based management stations can manage RADIUS   authentication servers.1.  Introduction   This memo defines a portion of the Management Information Base (MIB)   for use with network management protocols in the Internet community.   In particular, it describes managed objects used for managing RADIUS   authentication servers.   RADIUS authentication servers are today widely deployed by dialup   Internet Service Providers, in order to provide authentication   services.  As a result, the effective management of RADIUS   authentication servers is of considerable importance.Zorn & Aboba                Standards Track                     [Page 1]

RFC 2619            RADIUS Authentication Server MIB           June 19992.  The SNMP Management Framework   The SNMP Management Framework presently consists of five major   components:    o   An overall architecture, described inRFC 2571 [1].    o   Mechanisms for describing and naming objects and events for the        purpose of management.  The first version of this Structure of        Management Information (SMI) is called SMIv1 and described in        STD 16,RFC 1155 [2], STD 16,RFC 1212 [3] andRFC 1215 [4].        The second version, called SMIv2, is described in STD 58,RFC2578 [5],RFC 2579 [6] andRFC 2580 [7].    o   Message protocols for transferring management information. The        first version of the SNMP message protocol is called SNMPv1 and        described in STD 15,RFC 1157 [8]. A second version of the        SNMP message protocol, which is not an Internet standards        track protocol, is called SNMPv2c and described inRFC 1901        [9] andRFC 1906 [10].  The third version of the message        protocol is called SNMPv3 and described inRFC 1906 [10],RFC2572 [11] andRFC 2574 [12].    o   Protocol operations for accessing management information. The        first set of protocol operations and associated PDU formats is        described in STD 15,RFC 1157 [8]. A second set of protocol        operations and associated PDU formats is described inRFC 1905        [13].    o   A set of fundamental applications described inRFC 2573 [14] and        the view-based access control mechanism described inRFC 2575        [15].   Managed objects are accessed via a virtual information store, termed   the Management Information Base or MIB.  Objects in the MIB are   defined using the mechanisms defined in the SMI.   This memo specifies a MIB module that is compliant to the SMIv2.  A   MIB conforming to the SMIv1 can be produced through the appropriate   translations.  The resulting translated MIB must be semantically   equivalent, except where objects or events are omitted because no   translation is possible (use of Counter64).  Some machine readable   information in SMIv2 will be converted into textual descriptions in   SMIv1 during the translation process.  However, this loss of machine   readable information is not considered to change the semantics of the   MIB.Zorn & Aboba                Standards Track                     [Page 2]

RFC 2619            RADIUS Authentication Server MIB           June 19993.  Overview   The RADIUS authentication protocol, described in [16], distinguishes   between the client function and the server function.  In RADIUS   authentication, clients send Access-Requests, and servers reply with   Access-Accepts, Access-Rejects, and Access-Challenges.  Typically NAS   devices implement the client function, and thus would be expected to   implement the RADIUS authentication client MIB, while RADIUS   authentication servers implement the server function, and thus would   be expected to implement the RADIUS authentication server MIB.   However, it is possible for a RADIUS authentication entity to perform   both client and server functions. For example, a RADIUS proxy may act   as a server to one or more RADIUS authentication clients, while   simultaneously acting as an authentication client to one or more   authentication servers.  In such situations, it is expected that   RADIUS entities combining client and server functionality will   support both the client and server MIBs.3.1.  Selected objects   This MIB module contains fourteen scalars as well as a single table:   (1)  the RADIUS Authentication Client Table contains one row for        each RADIUS authentication client that the server shares a        secret with.   Each entry in the RADIUS Authentication Client Table includes twelve   columns presenting a view of the activity of the RADIUS   authentication server.4.  DefinitionsRADIUS-AUTH-SERVER-MIB DEFINITIONS ::= BEGINIMPORTS       MODULE-IDENTITY, OBJECT-TYPE, OBJECT-IDENTITY,       Counter32, Integer32,       IpAddress, TimeTicks, mib-2      FROM SNMPv2-SMI       SnmpAdminString                  FROM SNMP-FRAMEWORK-MIB       MODULE-COMPLIANCE, OBJECT-GROUP  FROM SNMPv2-CONF;radiusAuthServMIB MODULE-IDENTITY       LAST-UPDATED "9906110000Z"       ORGANIZATION "IETF RADIUS Working Group."       CONTACT-INFO              " Bernard Aboba                MicrosoftZorn & Aboba                Standards Track                     [Page 3]

RFC 2619            RADIUS Authentication Server MIB           June 1999                One Microsoft Way                Redmond, WA  98052                US                Phone: +1 425 936 6605                EMail: bernarda@microsoft.com"       DESCRIPTION             "The MIB module for entities implementing the server              side of the Remote Access Dialin User Service (RADIUS)              authentication protocol."       REVISION "9906110000Z"    --  11 Jun 1999       DESCRIPTION "Initial version as published inRFC 2619"       ::= { radiusAuthentication 1 }radiusMIB OBJECT-IDENTITY       STATUS  current       DESCRIPTION             "The OID assigned to RADIUS MIB work by the IANA."        ::= { mib-2 67 }radiusAuthentication  OBJECT IDENTIFIER ::= {radiusMIB 1}radiusAuthServMIBObjects     OBJECT IDENTIFIER ::=                                                 { radiusAuthServMIB 1 }radiusAuthServ      OBJECT IDENTIFIER ::= { radiusAuthServMIBObjects 1 }radiusAuthServIdent OBJECT-TYPE       SYNTAX      SnmpAdminString       MAX-ACCESS  read-only       STATUS      current       DESCRIPTION             "The implementation identification string for the              RADIUS authentication server software in use on the              system, for example; `FNS-2.1'"       ::= {radiusAuthServ 1}radiusAuthServUpTime OBJECT-TYPE       SYNTAX      TimeTicks       MAX-ACCESS  read-only       STATUS      current       DESCRIPTION             "If the server has a persistent state (e.g., a process),              this value will be the time elapsed (in hundredths of a              seco) since the server process was started.              For software without persistent state, this value will              be zero."       ::= {radiusAuthServ 2}Zorn & Aboba                Standards Track                     [Page 4]

RFC 2619            RADIUS Authentication Server MIB           June 1999radiusAuthServResetTime OBJECT-TYPE       SYNTAX      TimeTicks       MAX-ACCESS  read-only       STATUS      current       DESCRIPTION             "If the server has a persistent state (e.g., a process)              and supports a `reset' operation (e.g., can be told to              re-read configuration files), this value will be the              time elapsed (in hundredths of a second) since the              server was `reset.'  For software that does not              have persistence or does not support a `reset' operation,              this value will be zero."       ::= {radiusAuthServ 3}radiusAuthServConfigReset OBJECT-TYPE       SYNTAX INTEGER { other(1),                        reset(2),                        initializing(3),                        running(4)}       MAX-ACCESS  read-write       STATUS      current       DESCRIPTION              "Status/action object to reinitialize any persistent               server state.  When set to reset(2), any persistent               server state (such as a process) is reinitialized as if               the server had just been started.  This value will               never be returned by a read operation.  When read, one of               the following values will be returned:                   other(1) - server in some unknown state;                   initializing(3) - server (re)initializing;                   running(4) - server currently running."       ::= {radiusAuthServ 4}-- New Stats proposed by Dale E. Reed Jr (daler@iea-software.com)radiusAuthServTotalAccessRequests OBJECT-TYPE        SYNTAX Counter32        MAX-ACCESS read-only        STATUS current        DESCRIPTION               "The number of packets received on the                authentication port."        ::= { radiusAuthServ 5}radiusAuthServTotalInvalidRequests OBJECT-TYPE        SYNTAX Counter32        MAX-ACCESS read-only        STATUS currentZorn & Aboba                Standards Track                     [Page 5]

RFC 2619            RADIUS Authentication Server MIB           June 1999        DESCRIPTION              "The number of RADIUS Access-Request packets               received from unknown addresses."        ::= { radiusAuthServ 6 }radiusAuthServTotalDupAccessRequests OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of duplicate RADIUS Access-Request              packets received."       ::= { radiusAuthServ 7 }radiusAuthServTotalAccessAccepts OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of RADIUS Access-Accept packets sent."       ::= { radiusAuthServ 8 }radiusAuthServTotalAccessRejects OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of RADIUS Access-Reject packets sent."      ::= { radiusAuthServ 9 }radiusAuthServTotalAccessChallenges OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of RADIUS Access-Challenge packets sent."      ::= { radiusAuthServ 10 }radiusAuthServTotalMalformedAccessRequests OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of malformed RADIUS Access-Request             packets received. Bad authenticators             and unknown types are not included as             malformed Access-Requests."      ::= { radiusAuthServ 11 }Zorn & Aboba                Standards Track                     [Page 6]

RFC 2619            RADIUS Authentication Server MIB           June 1999radiusAuthServTotalBadAuthenticators OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of RADIUS Authentication-Request packets             which contained invalid Signature attributes received."      ::= { radiusAuthServ 12 }radiusAuthServTotalPacketsDropped OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of incoming packets             silently discarded for some reason other             than malformed, bad authenticators or             unknown types."      ::= { radiusAuthServ 13 }radiusAuthServTotalUnknownTypes OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION            "The number of RADIUS packets of unknown type which             were received."      ::= { radiusAuthServ 14 }-- End of newradiusAuthClientTable OBJECT-TYPE       SYNTAX     SEQUENCE OF RadiusAuthClientEntry       MAX-ACCESS not-accessible       STATUS     current       DESCRIPTION             "The (conceptual) table listing the RADIUS authentication              clients with which the server shares a secret."       ::= { radiusAuthServ 15 }radiusAuthClientEntry OBJECT-TYPE       SYNTAX     RadiusAuthClientEntry       MAX-ACCESS not-accessible       STATUS     current       DESCRIPTION             "An entry (conceptual row) representing a RADIUS              authentication client with which the server shares a              secret."Zorn & Aboba                Standards Track                     [Page 7]

RFC 2619            RADIUS Authentication Server MIB           June 1999       INDEX      { radiusAuthClientIndex }       ::= { radiusAuthClientTable 1 }RadiusAuthClientEntry ::= SEQUENCE {       radiusAuthClientIndex                           Integer32,       radiusAuthClientAddress                         IpAddress,       radiusAuthClientID                        SnmpAdminString,       radiusAuthServAccessRequests                    Counter32,       radiusAuthServDupAccessRequests                 Counter32,       radiusAuthServAccessAccepts                     Counter32,       radiusAuthServAccessRejects                     Counter32,       radiusAuthServAccessChallenges                  Counter32,       radiusAuthServMalformedAccessRequests           Counter32,       radiusAuthServBadAuthenticators                 Counter32,       radiusAuthServPacketsDropped                    Counter32,       radiusAuthServUnknownTypes                      Counter32}radiusAuthClientIndex OBJECT-TYPE       SYNTAX     Integer32 (1..2147483647)       MAX-ACCESS not-accessible       STATUS     current       DESCRIPTION             "A number uniquely identifying each RADIUS              authentication client with which this server              communicates."       ::= { radiusAuthClientEntry 1 }radiusAuthClientAddress OBJECT-TYPE       SYNTAX     IpAddress       MAX-ACCESS read-only       STATUS     current       DESCRIPTION             "The NAS-IP-Address of the RADIUS authentication client              referred to in this table entry."       ::= { radiusAuthClientEntry 2 }radiusAuthClientID OBJECT-TYPE       SYNTAX     SnmpAdminString       MAX-ACCESS read-only       STATUS     current       DESCRIPTION             "The NAS-Identifier of the RADIUS authentication client              referred to in this table entry. This is not necessarily              the same as sysName in MIB II."       ::= { radiusAuthClientEntry 3 }-- Server CountersZorn & Aboba                Standards Track                     [Page 8]

RFC 2619            RADIUS Authentication Server MIB           June 1999---- Responses = AccessAccepts + AccessRejects + AccessChallenges---- Requests - DupRequests - BadAuthenticators - MalformedRequests --- UnknownTypes -  PacketsDropped - Responses = Pending---- Requests - DupRequests - BadAuthenticators - MalformedRequests --- UnknownTypes - PacketsDropped = entries loggedradiusAuthServAccessRequests OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of packets received on the authentication              port from this client."       ::= { radiusAuthClientEntry  4 }radiusAuthServDupAccessRequests OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of duplicate RADIUS Access-Request              packets received from this client."       ::= { radiusAuthClientEntry  5 }radiusAuthServAccessAccepts OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of RADIUS Access-Accept packets              sent to this client."       ::= { radiusAuthClientEntry  6 }radiusAuthServAccessRejects OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION             "The number of RADIUS Access-Reject packets              sent to this client."       ::= { radiusAuthClientEntry  7 }radiusAuthServAccessChallenges OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-onlyZorn & Aboba                Standards Track                     [Page 9]

RFC 2619            RADIUS Authentication Server MIB           June 1999       STATUS current       DESCRIPTION             "The number of RADIUS Access-Challenge packets              sent to this client."       ::= { radiusAuthClientEntry  8 }radiusAuthServMalformedAccessRequests OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of malformed RADIUS Access-Request              packets received from this client.              Bad authenticators and unknown types are not included as              malformed Access-Requests."       ::= { radiusAuthClientEntry  9 }radiusAuthServBadAuthenticators OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of RADIUS Authentication-Request packets              which contained invalid Signature attributes received              from this client."       ::= { radiusAuthClientEntry  10 }radiusAuthServPacketsDropped OBJECT-TYPE      SYNTAX Counter32      MAX-ACCESS read-only      STATUS current      DESCRIPTION              "The number of incoming packets from this               client silently discarded for some reason other               than malformed, bad authenticators or               unknown types."       ::= { radiusAuthClientEntry  11 }radiusAuthServUnknownTypes OBJECT-TYPE       SYNTAX Counter32       MAX-ACCESS read-only       STATUS current       DESCRIPTION             "The number of RADIUS packets of unknown type which              were received from this client."       ::= { radiusAuthClientEntry  12 }Zorn & Aboba                Standards Track                    [Page 10]

RFC 2619            RADIUS Authentication Server MIB           June 1999-- conformance informationradiusAuthServMIBConformance              OBJECT IDENTIFIER ::= { radiusAuthServMIB 2 }radiusAuthServMIBCompliances              OBJECT IDENTIFIER ::= { radiusAuthServMIBConformance 1 }radiusAuthServMIBGroups              OBJECT IDENTIFIER ::= { radiusAuthServMIBConformance 2 }-- compliance statementsradiusAuthServMIBCompliance MODULE-COMPLIANCE            STATUS  current            DESCRIPTION                  "The compliance statement for authentication servers                   implementing the RADIUS Authentication Server MIB."            MODULE  -- this module            MANDATORY-GROUPS { radiusAuthServMIBGroup }            OBJECT        radiusAuthServConfigReset            WRITE-SYNTAX  INTEGER { reset(2) }            DESCRIPTION  "The only SETable value is 'reset' (2)."            ::= { radiusAuthServMIBCompliances 1 }-- units of conformanceradiusAuthServMIBGroup OBJECT-GROUP      OBJECTS {radiusAuthServIdent,               radiusAuthServUpTime,               radiusAuthServResetTime,               radiusAuthServConfigReset,               radiusAuthServTotalAccessRequests,               radiusAuthServTotalInvalidRequests,               radiusAuthServTotalDupAccessRequests,               radiusAuthServTotalAccessAccepts,               radiusAuthServTotalAccessRejects,               radiusAuthServTotalAccessChallenges,               radiusAuthServTotalMalformedAccessRequests,               radiusAuthServTotalBadAuthenticators,               radiusAuthServTotalPacketsDropped,               radiusAuthServTotalUnknownTypes,               radiusAuthClientAddress,               radiusAuthClientID,               radiusAuthServAccessRequests,               radiusAuthServDupAccessRequests,               radiusAuthServAccessAccepts,Zorn & Aboba                Standards Track                    [Page 11]

RFC 2619            RADIUS Authentication Server MIB           June 1999               radiusAuthServAccessRejects,               radiusAuthServAccessChallenges,               radiusAuthServMalformedAccessRequests,               radiusAuthServBadAuthenticators,               radiusAuthServPacketsDropped,               radiusAuthServUnknownTypes              }      STATUS  current      DESCRIPTION            "The collection of objects providing management of             a RADIUS Authentication Server."      ::= { radiusAuthServMIBGroups 1 }END5.  References   [1]  Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for        Describing SNMP Management Frameworks",RFC 2571, April 1999.   [2]  Rose, M., and K. McCloghrie, "Structure and Identification of        Management Information for TCP/IP-based Internets", STD 16,RFC1155, May 1990.   [3]  Rose, M., and K. McCloghrie, "Concise MIB Definitions", STD 16,RFC 1212, March 1991.   [4]  Rose, M., "A Convention for Defining Traps for use with the        SNMP",RFC 1215, March 1991.   [5]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,        M. and S. Waldbusser, "Structure of Management Information        Version 2 (SMIv2)", STD 58,RFC 2578, April 1999.   [6]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,        M. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58,RFC 2579, April 1999.   [7]  McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,        M. and S. Waldbusser, "Conformance Statements for SMIv2", STD        58,RFC 2580, April 1999.   [8]  Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple        Network Management Protocol", STD 15,RFC 1157, May 1990.   [9]  Case, J., McCloghrie, K., Rose, M., and S.  Waldbusser,        "Introduction  to Community-based SNMPv2",RFC 1901, January        1996.Zorn & Aboba                Standards Track                    [Page 12]

RFC 2619            RADIUS Authentication Server MIB           June 1999   [10] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser,        "Transport Mappings for Version 2 of the Simple  Network        Management  Protocol (SNMPv2)",RFC 1906, January 1996.   [11] Case, J., Harrington D., Presuhn R., and B. Wijnen, "Message        Processing  and  Dispatching  for  the  Simple  Network        Management Protocol (SNMP)",RFC 2572, April 1999.   [12] Blumenthal, U., and B. Wijnen, "User-based Security Model for        Version 3 of the Simple Network Management Protocol (SNMPv3)",RFC 2574, April 1999.   [13] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol        Operations for Version 2 of the Simple Network Management        Protocol (SNMPv2)",RFC 1905, January 1996.   [14] Levi, D., Meyer, P., and B. Stewart, "SNMP Applications",RFC2573, April 1999.   [15] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access        Control Model for the Simple Network Management Protocol        (SNMP)",RFC 2575, April 1999.   [16] Rigney, C., Rubens, A., Simpson W. and S. Willens, "Remote        Authentication Dial In User Service (RADIUS)",RFC 2138, April        1997.6.  Security Considerations   There are a number of management objects defined in this MIB that   have a MAX-ACCESS clause of read-write and/or read-create.  Such   objects may be considered sensitive or vulnerable in some network   environments.  The support for SET operations in a non-secure   environment without proper protection can have a negative effect on   network operations.   There are a number of managed objects in this MIB that may contain   sensitive information. These are:   radiusAuthClientAddress             This can be used to determine the address of the RADIUS             authentication client with which the server is             communicating.  This information could be useful in             impersonating the client.   radiusAuthClientID This can be used to determine the client ID of the             authentication client with which the server is             communicating.  This information could be useful inZorn & Aboba                Standards Track                    [Page 13]

RFC 2619            RADIUS Authentication Server MIB           June 1999             impersonating the client.   It is thus important to control even GET access to these objects and   possibly to even encrypt the values of these object when sending them   over the network via SNMP.  Not all versions of SNMP provide features   for such a secure environment.   SNMPv1 by itself is not a secure environment. Even if the network   itself is secure (for example by using IPSec), there is no control as   to who on the secure network is allowed to access and GET/SET   (read/change/create/delete) the objects in this MIB.   It is recommended that the implementers consider the security   features as provided by the SNMPv3 framework. Specifically, the use   of the User-based Security ModelRFC 2574 [12] and the View-based   Access Control ModelRFC 2575 [15] is recommended.  Using these   security features, customer/users can give access to the objects only   to those principals (users) that have legitimate rights to GET or SET   (change/create/delete) them.7.  Acknowledgments   The authors acknowledge the contributions of the RADIUS Working Group   in the development of this MIB.  Thanks to Narendra Gidwani of   Microsoft, Allan C. Rubens of MERIT, Carl Rigney of Livingston and   Peter Heitman of American Internet Corporation for useful discussions   of this problem space.8.  Authors' Addresses   Bernard Aboba   Microsoft Corporation   One Microsoft Way   Redmond, WA 98052   Phone: 425-936-6605   EMail: bernarda@microsoft.com   Glen Zorn   Microsoft Corporation   One Microsoft Way   Redmond, WA 98052   Phone: 425-703-1559   EMail: glennz@microsoft.com9.  Intellectural Property StatementZorn & Aboba                Standards Track                    [Page 14]

RFC 2619            RADIUS Authentication Server MIB           June 1999   The IETF takes no position regarding the validity or scope of any   intellectual property 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; neither does it represent that it   has made any effort to identify any such rights.  Information on the   IETF's procedures with respect to rights in standards-track and   standards- related documentation can be found inBCP-11.  Copies of   claims of rights made available for publication 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 implementors or users of this specification can   be obtained from the IETF Secretariat.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights which may cover technology that may be required to practice   this standard.  Please address the information to the IETF Executive   Director.Zorn & Aboba                Standards Track                    [Page 15]

RFC 2619            RADIUS Authentication Server MIB           June 199910.  Full Copyright Statement   Copyright (C) The Internet Society (1999).  All Rights Reserved.   This document and translations of it may be copied and furnished to   others, and derivative works that comment on or otherwise explain it   or assist in its implmentation may be prepared, copied, published and   distributed, in whole or in part, without restriction of any kind,   provided that the above copyright notice and this paragraph are   included on all such copies and derivative works.  However, this   document itself may not be modified in any way, such as by removing   the copyright notice or references to the Internet Society or other   Internet organizations, except as needed for the purpose of   developing Internet standards in which case the procedures for   copyrights defined in the Internet Standards process must be   followed, or as required to translate it into languages other than   English.   The limited permissions granted above are perpetual and will not be   revoked by the Internet Society or its successors or assigns.   This document and the information contained herein is provided on an   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING   TASK FORCE DISCLAIMS 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.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Zorn & Aboba                Standards Track                    [Page 16]