RADIUS Client MIB: RADIUS Authentication Client MIB

Network Working Group                                            B. Aboba
Request for Comments: 2618                                        G. Zorn
Category: Standards Track                                       Microsoft
                                                                June 1999


                    RADIUS Authentication Client MIB

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 Internet Society (1999).  All Rights Reserved.

Abstract

   This memo defines a set of extensions which instrument RADIUS
   authentication client 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 clients.

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 clients.

   Today a wide range of network devices, including routers and NASes,
   act as RADIUS authentication clients in order to provide
   authentication and authorization services. As a result, the effective
   management of RADIUS authentication clients is of considerable
   importance.

2.  The SNMP Management Framework

   The SNMP Management Framework presently consists of five major
   components:

    o   An overall architecture, described in RFC 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] and RFC 1215 [4].
        The second version, called SMIv2, is described in STD 58, RFC
        2578 [5], RFC 2579 [6] and RFC 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 in RFC 1901
        [9] and RFC 1906 [10].  The third version of the message
        protocol is called SNMPv3 and described in RFC 1906 [10], RFC
        2572 [11] and RFC 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 in RFC 1905
        [13].

    o   A set of fundamental applications described in RFC 2573 [14] and
        the view-based access control mechanism described in RFC 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.

3.  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 two scalars as well as a single table:

   (1)  the RADIUS Authentication Server Table contains one row for
        each RADIUS authentication server that the client shares a
        secret with.

   Each entry in the RADIUS Authentication Server Table includes fifteen
   columns presenting a view of the activity of the RADIUS
   authentication client.

4.  Definitions

RADIUS-AUTH-CLIENT-MIB DEFINITIONS ::= BEGIN

IMPORTS
       MODULE-IDENTITY, OBJECT-TYPE, OBJECT-IDENTITY,
       Counter32, Integer32, Gauge32,
       IpAddress, TimeTicks, mib-2      FROM SNMPv2-SMI
       SnmpAdminString                  FROM SNMP-FRAMEWORK-MIB
       MODULE-COMPLIANCE, OBJECT-GROUP  FROM SNMPv2-CONF;

radiusAuthClientMIB MODULE-IDENTITY
       LAST-UPDATED "9906110000Z" -- 11 Jun 1999
       ORGANIZATION "IETF RADIUS Working Group."
       CONTACT-INFO
              " Bernard Aboba
                Microsoft
                One Microsoft Way
                Redmond, WA  98052
                US

                Phone: +1 425 936 6605
                EMail: bernarda@microsoft.com"
       DESCRIPTION
             "The MIB module for entities implementing the client
              side of the Remote Access Dialin User Service (RADIUS)
              authentication protocol."
       REVISION "9906110000Z"    -- 11 Jun 1999
       DESCRIPTION "Initial version as published in RFC 2618"
       ::= { radiusAuthentication 2 }

radiusMIB OBJECT-IDENTITY
       STATUS  current
       DESCRIPTION
             "The OID assigned to RADIUS MIB work by the IANA."
        ::= { mib-2 67 }

radiusAuthentication  OBJECT IDENTIFIER ::= {radiusMIB 1}

radiusAuthClientMIBObjects     OBJECT IDENTIFIER ::=
                                               { radiusAuthClientMIB 1 }

radiusAuthClient  OBJECT IDENTIFIER ::= { radiusAuthClientMIBObjects 1 }

radiusAuthClientInvalidServerAddresses OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Response packets
             received from unknown addresses."
      ::= { radiusAuthClient 1 }

radiusAuthClientIdentifier OBJECT-TYPE
      SYNTAX SnmpAdminString
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
             "The NAS-Identifier of the RADIUS authentication client.
              This is not necessarily the same as sysName in MIB II."
      ::= { radiusAuthClient 2 }

radiusAuthServerTable OBJECT-TYPE
      SYNTAX     SEQUENCE OF RadiusAuthServerEntry
      MAX-ACCESS not-accessible
      STATUS     current
      DESCRIPTION
            "The (conceptual) table listing the RADIUS authentication
             servers with which the client shares a secret."
      ::= { radiusAuthClient 3 }

radiusAuthServerEntry OBJECT-TYPE
      SYNTAX     RadiusAuthServerEntry
      MAX-ACCESS not-accessible
      STATUS     current
      DESCRIPTION
            "An entry (conceptual row) representing a RADIUS
             authentication server with which the client shares
             a secret."
      INDEX      { radiusAuthServerIndex }
      ::= { radiusAuthServerTable 1 }

RadiusAuthServerEntry ::= SEQUENCE {
      radiusAuthServerIndex                           Integer32,
      radiusAuthServerAddress                         IpAddress,
      radiusAuthClientServerPortNumber                Integer32,
      radiusAuthClientRoundTripTime                   TimeTicks,
      radiusAuthClientAccessRequests                  Counter32,
      radiusAuthClientAccessRetransmissions           Counter32,
      radiusAuthClientAccessAccepts                   Counter32,
      radiusAuthClientAccessRejects                   Counter32,
      radiusAuthClientAccessChallenges                Counter32,
      radiusAuthClientMalformedAccessResponses        Counter32,
      radiusAuthClientBadAuthenticators               Counter32,
      radiusAuthClientPendingRequests                   Gauge32,
      radiusAuthClientTimeouts                        Counter32,
      radiusAuthClientUnknownTypes                    Counter32,
      radiusAuthClientPacketsDropped                  Counter32
}

radiusAuthServerIndex OBJECT-TYPE
      SYNTAX     Integer32 (1..2147483647)
      MAX-ACCESS not-accessible
      STATUS     current
      DESCRIPTION
             "A number uniquely identifying each RADIUS
             Authentication server with which this client
             communicates."
      ::= { radiusAuthServerEntry 1 }

radiusAuthServerAddress OBJECT-TYPE
      SYNTAX     IpAddress
      MAX-ACCESS read-only
      STATUS     current
      DESCRIPTION
            "The IP address of the RADIUS authentication server
             referred to in this table entry."
      ::= { radiusAuthServerEntry 2 }

radiusAuthClientServerPortNumber  OBJECT-TYPE
      SYNTAX Integer32 (0..65535)
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The UDP port the client is using to send requests to
             this server."
      ::= { radiusAuthServerEntry 3 }

radiusAuthClientRoundTripTime  OBJECT-TYPE
      SYNTAX TimeTicks
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The time interval (in hundredths of a second) between
             the most recent Access-Reply/Access-Challenge and the
             Access-Request that matched it from this RADIUS
             authentication server."
      ::= { radiusAuthServerEntry 4 }

-- Request/Response statistics
--
-- TotalIncomingPackets = Accepts + Rejects + Challenges + UnknownTypes
--
-- TotalIncomingPackets - MalformedResponses - BadAuthenticators -
-- UnknownTypes - PacketsDropped = Successfully received
--
-- AccessRequests + PendingRequests + ClientTimeouts =
-- Successfully Received
--
--

radiusAuthClientAccessRequests OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Request packets sent
             to this server. This does not include retransmissions."
      ::= { radiusAuthServerEntry 5 }

radiusAuthClientAccessRetransmissions OBJECT-TYPE

      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Request packets
             retransmitted to this RADIUS authentication server."
      ::= { radiusAuthServerEntry 6 }

radiusAuthClientAccessAccepts OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Accept packets
             (valid or invalid) received from this server."
      ::= { radiusAuthServerEntry 7 }

radiusAuthClientAccessRejects OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Reject packets
             (valid or invalid) received from this server."
      ::= { radiusAuthServerEntry  8 }

radiusAuthClientAccessChallenges OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Challenge packets
             (valid or invalid) received from this server."
      ::= { radiusAuthServerEntry 9 }

-- "Access-Response" includes an Access-Accept, Access-Challenge
-- or Access-Reject

radiusAuthClientMalformedAccessResponses OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of malformed RADIUS Access-Response
             packets received from this server.
             Malformed packets include packets with
             an invalid length. Bad authenticators or
             Signature attributes or unknown types are not
             included as malformed access responses."
      ::= { radiusAuthServerEntry 10 }

radiusAuthClientBadAuthenticators OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Response packets
             containing invalid authenticators or Signature
             attributes received from this server."
      ::= { radiusAuthServerEntry 11 }

radiusAuthClientPendingRequests OBJECT-TYPE
      SYNTAX Gauge32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS Access-Request packets
             destined for this server that have not yet timed out
             or received a response. This variable is incremented
             when an Access-Request is sent and decremented due to
             receipt of an Acess-Accept, Access-Reject or
             Access-Challenge, a timeout or retransmission."
      ::= { radiusAuthServerEntry 12 }

radiusAuthClientTimeouts OBJECT-TYPE
     SYNTAX Counter32
     MAX-ACCESS read-only
     STATUS current
     DESCRIPTION
            "The number of authentication timeouts to this server.
             After a timeout the client may retry to the same
             server, send to a different server, or
             give up. A retry to the same server is counted as a
             retransmit as well as a timeout. A send to a different
             server is counted as a Request as well as a timeout."
      ::= { radiusAuthServerEntry  13 }

radiusAuthClientUnknownTypes OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS packets of unknown type which
             were received from this server on the authentication port."
      ::= { radiusAuthServerEntry  14 }

radiusAuthClientPacketsDropped OBJECT-TYPE
      SYNTAX Counter32
      MAX-ACCESS read-only
      STATUS current
      DESCRIPTION
            "The number of RADIUS packets of which were
             received from this server on the authentication port
             and dropped for some other reason."
      ::= { radiusAuthServerEntry  15 }


-- conformance information

radiusAuthClientMIBConformance
             OBJECT IDENTIFIER ::= { radiusAuthClientMIB 2 }
radiusAuthClientMIBCompliances
             OBJECT IDENTIFIER ::= { radiusAuthClientMIBConformance 1 }
radiusAuthClientMIBGroups
             OBJECT IDENTIFIER ::= { radiusAuthClientMIBConformance 2 }


-- compliance statements

radiusAuthClientMIBCompliance MODULE-COMPLIANCE
     STATUS  current
     DESCRIPTION
           "The compliance statement for authentication clients
            implementing the RADIUS Authentication Client MIB."
     MODULE  -- this module
            MANDATORY-GROUPS { radiusAuthClientMIBGroup }

     ::= { radiusAuthClientMIBCompliances 1 }


-- units of conformance

radiusAuthClientMIBGroup OBJECT-GROUP
     OBJECTS { radiusAuthClientIdentifier,
               radiusAuthClientInvalidServerAddresses,
               radiusAuthServerAddress,
               radiusAuthClientServerPortNumber,
               radiusAuthClientRoundTripTime,
               radiusAuthClientAccessRequests,
               radiusAuthClientAccessRetransmissions,
               radiusAuthClientAccessAccepts,
               radiusAuthClientAccessRejects,
               radiusAuthClientAccessChallenges,
               radiusAuthClientMalformedAccessResponses,
               radiusAuthClientBadAuthenticators,
               radiusAuthClientPendingRequests,
               radiusAuthClientTimeouts,
               radiusAuthClientUnknownTypes,
               radiusAuthClientPacketsDropped
            }
     STATUS  current
     DESCRIPTION
           "The basic collection of objects providing management of
            RADIUS Authentication Clients."
     ::= { radiusAuthClientMIBGroups 1 }

END

5.  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, RFC
        1155, 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, Performance Systems International, 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.

   [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", RFC
        2573, 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 no management objects defined in this MIB that have a MAX-
   ACCESS clause of read-write and/or read-create.  So, if this MIB is
   implemented correctly, then there is no risk that an intruder can
   alter or create any management objects of this MIB via direct SNMP
   SET operations.

   There are a number of managed objects in this MIB that may contain
   sensitive information. These are:

   radiusAuthServerAddress
             This can be used to determine the address of the RADIUS
             authentication server with which the client is
             communicating.  This information could be useful in
             mounting an attack on the authentication server.

   radiusAuthClientServerPortNumber This can be used to determine the
             port number on which the RADIUS authentication client is
             sending. This information could be useful in impersonating
             the client in order to send data to the authentication
             server.

   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 Model RFC 2574 [12] and the View-based
   Access Control Model RFC 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 Wy
   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.com

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