Status of this Memo

This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. 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 accounting 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 accounting 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 accounting clients.

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

2. The SNMP Management Framework

The SNMP Management Framework presently consists of five major components:

• An overall architecture, described in RFC 2571 [1].
  
  
• 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 15, 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].

• 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].
     
     
• 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. .
      
      
• 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 poduced 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 accounting protocol, described in [16], distinguishes between the client function and the server function. In RADIUS accounting, clients send Accounting-Requests, and servers reply with Accounting-Responses. Typically NAS devices implement the client function, and thus would be expected to implement the RADIUS accounting client MIB, while RADIUS accounting servers implement the server function, and thus would be expected to implement the RADIUS accounting server MIB.

However, it is possible for a RADIUS accounting entity to perform both client and server functions. For example, a RADIUS proxy may act as a server to one or more RADIUS accounting clients, while simultaneously acting as an accounting client to one or more accounting 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 Accounting Server Table contains one row for each RADIUS server that the client shares a secret with.

Each entry in the RADIUS Accounting Server Table includes thirteen columns presenting a view of the activity of the RADIUS client.

4. Definitions

RADIUS-ACC-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;

radiusAccClientMIB 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) accounting protocol."

REVISION "9906110000Z" -- 11 Jun 1999
DESCRIPTION "Initial version as published in RFC 2620"
::= { radiusAccounting 2 }

radiusMIB OBJECT-IDENTITY

STATUS current
DESCRIPTION

             "The OID assigned to RADIUS MIB work by the IANA."
       ::= { mib-2 67 }

radiusAccounting  OBJECT IDENTIFIER ::= {radiusMIB 2}

radiusAccClientMIBObjects     OBJECT IDENTIFIER ::=
                                              { radiusAccClientMIB 1 }

radiusAccClient OBJECT IDENTIFIER ::= { radiusAccClientMIBObjects 1 }

radiusAccClientInvalidServerAddresses OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS Accounting-Response packets

received from unknown addresses."
::= { radiusAccClient 1 }

radiusAccClientIdentifier OBJECT-TYPE

SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The NAS-Identifier of the RADIUS accounting client. This

is not necessarily the same as sysName in MIB II."
::= { radiusAccClient 2 }

radiusAccServerTable OBJECT-TYPE

SYNTAX SEQUENCE OF RadiusAccServerEntry MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The (conceptual) table listing the RADIUS accounting

servers with which the client shares a secret."
::= { radiusAccClient 3 }

radiusAccServerEntry OBJECT-TYPE

SYNTAX RadiusAccServerEntry MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry (conceptual row) representing a RADIUS

	accounting server with which the client shares a secret."
INDEX	{ radiusAccServerIndex }

::= { radiusAccServerTable 1 }

radiusAccServerIndex OBJECT-TYPE

SYNTAX Integer32 (1..2147483647) MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A number uniquely identifying each RADIUS

Accounting server with which this client

communicates."
::= { radiusAccServerEntry 1 }

radiusAccServerAddress OBJECT-TYPE

SYNTAX IpAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The IP address of the RADIUS accounting server

referred to in this table entry."
::= { radiusAccServerEntry 2 }

radiusAccClientServerPortNumber 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."
::= { radiusAccServerEntry 3 }

radiusAccClientRoundTripTime OBJECT-TYPE

SYNTAX TimeTicks

MAX-ACCESS read-only
STATUS current
DESCRIPTION

"The time interval between the most recent Accounting-Response and the Accounting-Request that

matched it from this RADIUS accounting server."
::= { radiusAccServerEntry 4 }

-- Request/Response statistics
--
-- Requests = Responses + PendingRequests + ClientTimeouts --
-- Responses - MalformedResponses - BadAuthenticators - -- UnknownTypes - PacketsDropped = Successfully received

radiusAccClientRequests OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS Accounting-Request packets

sent. This does not include retransmissions."
::= { radiusAccServerEntry 5 }

radiusAccClientRetransmissions OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS Accounting-Request packets

retransmitted to this RADIUS accounting server. Retransmissions include retries where the Identifier and Acct-Delay have been updated, as

well as those in which they remain the same."
::= { radiusAccServerEntry 6 }

radiusAccClientResponses OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS packets received on the

accounting port from this server."
::= { radiusAccServerEntry 7 }

radiusAccClientMalformedResponses OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only

STATUS current
DESCRIPTION

"The number of malformed RADIUS Accounting-Response packets received from this server. Malformed packets include packets with an invalid length. Bad authenticators and unknown types are not included as

malformed accounting responses."
::= { radiusAccServerEntry 8 }

radiusAccClientBadAuthenticators OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS Accounting-Response

packets which contained invalid authenticators

received from this server."
::= { radiusAccServerEntry 9 }

radiusAccClientPendingRequests OBJECT-TYPE

SYNTAX Gauge32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS Accounting-Request packets

sent to this server that have not yet timed out or received a response. This variable is incremented when an Accounting-Request is sent and decremented due to receipt of an Accounting-Response, a timeout or

a retransmission."
::= { radiusAccServerEntry 10 }

radiusAccClientTimeouts OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION

"The number of accounting 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 an Accounting-Request as well as

a timeout."
::= { radiusAccServerEntry	11 }

radiusAccClientUnknownTypes 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 accounting port."
::= { radiusAccServerEntry 12 }

radiusAccClientPacketsDropped OBJECT-TYPE

SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of RADIUS packets which were received from

this server on the accounting port and dropped for some

other reason."
::= { radiusAccServerEntry	13 }

-- conformance information

-- compliance statements

radiusAccClientMIBCompliance MODULE-COMPLIANCE

STATUS current
DESCRIPTION

"The compliance statement for accounting clients implementing the RADIUS Accounting Client MIB."

MODULE -- this module
MANDATORY-GROUPS { radiusAccClientMIBGroup }

::= { radiusAccClientMIBCompliances 1 }

-- units of conformance

radiusAccClientMIBGroup OBJECT-GROUP

OBJECTS { radiusAccClientIdentifier,

radiusAccClientInvalidServerAddresses, radiusAccServerAddress, radiusAccClientServerPortNumber, radiusAccClientRoundTripTime, radiusAccClientRequests,

radiusAccClientRetransmissions, radiusAccClientResponses, radiusAccClientMalformedResponses, radiusAccClientBadAuthenticators, radiusAccClientPendingRequests, radiusAccClientTimeouts, radiusAccClientUnknownTypes,

               radiusAccClientPacketsDropped
         }
     STATUS  current
     DESCRIPTION
           "The basic collection of objects providing management of
            RADIUS Accounting Clients."
     ::= { radiusAccClientMIBGroups 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,
   13. 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,
   13. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.
       
       
7. McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
   13. 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., "RADIUS Accounting", RFC 2139, 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 opertions.

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

radiusAccServerAddress

This can be used to determine the address of the RADIUS accounting server with which the client is communicating. This information could be useful in mounting an attack on the acounting server, which may contain sensitive financial data.

radiusAccClientServerPortNumber This can be used to determine the

port number on which the RADIUS accounting client is sending. This information could be useful in impersonating the client in order to send fraudulent data to the accounting 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 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.com

9. 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.

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