RADIUS Working Group Bernard Aboba INTERNET-DRAFT Microsoft Category: Informational Glen Zorn Microsoft 11 November 1998 RADIUS Accounting Client MIB 1. Status of this Memo This document is an Internet-Draft. Internet-Drafts are working docu- ments of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute work- ing documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference mate- rial or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ftp.ietf.org (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). The distribution of this memo is unlimited. It is filed as , and expires May 1, 1999. Please send comments to the authors. 2. Abstract This memo defines a set of extensions which instrument RADIUS account- ing client functions. These extensions represent a portion of the Man- agement Information Base (MIB) for use with network management proto- cols in the Internet community. Using these extensions IP-based man- agement stations can manage RADIUS accounting clients. 3. 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 ser- vices. As a result, the effective management of RADIUS accounting clients is of considerable importance. Aboba & Zorn Informational [Page 1] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 4. The SNMP Management Framework The SNMP Management Framework presently consists of five major compo- nents: o An overall architecture, described in RFC 2271 [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 RFC 1155 [2], RFC 1212 [3] and RFC 1215 [4]. The second version, called SMIv2, is described in RFC 1902 [5], RFC 1903 [6] and RFC 1904 [7]. o Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in 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 2272 [11] and RFC 2274 [12]. o Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in 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 2273 [14] and the view-based access control mechanism described in RFC 2275 [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 trans- lations. 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 informa- tion is not considered to change the semantics of the MIB. 5. 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 func- tion, and thus would be expected to implement the RADIUS accounting client MIB, while RADIUS accounting servers implement the server Aboba & Zorn Informational [Page 2] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 function, and thus woud be expected o 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. 5.1. 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. 6. Definitions RADIUS-ACC-CLIENT-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, OBJECT-IDENTITY, experimental, Counter32, Integer32, Gauge32, IpAddress, TimeTicks FROM SNMPv2-SMI DisplayString FROM SNMPv2-TC MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF; radius OBJECT-IDENTITY STATUS current DESCRIPTION "The OID assigned to RADIUS MIB work by the IANA." ::= { experimental 79 } radiusAccounting OBJECT IDENTIFIER ::= {radius 2} radiusAccClientMIB MODULE-IDENTITY LAST-UPDATED "9811161659Z" 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 Aboba & Zorn Informational [Page 3] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 "The MIB module for entities implementing the client side of the Remote Access Dialin User Service (RADIUS) accounting protocol." ::= { radiusAccounting 2 } radiusAccClientMIBObjects OBJECT IDENTIFIER ::= { radiusAccClientMIB 1 } radiusAccClient OBJECT IDENTIFIER ::= { radiusAccClientMIBObjects 1 } radiusAccClientInvalidServerAddresses OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of RADIUS Accounting-Response packets received from unknown addresses since client start-up." ::= { radiusAccClient 1 } radiusAccClientIdentifier OBJECT-TYPE SYNTAX DisplayString 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 } RadiusAccServerEntry ::= SEQUENCE { radiusAccServerIndex Integer32, radiusAccServerAddress IpAddress, radiusAccClientServerPortNumber Integer32, radiusAccClientRoundTripTime TimeTicks, radiusAccClientRequests Counter32, radiusAccClientRetransmissions Counter32, radiusAccClientResponses Counter32, Aboba & Zorn Informational [Page 4] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 radiusAccClientMalformedResponses Counter32, radiusAccClientBadAuthenticators Counter32, radiusAccClientPendingRequests Gauge32, radiusAccClientTimeouts Counter32, radiusAccClientUnknownTypes Counter32, radiusAccClientPacketsDropped Counter32 } radiusAccServerIndex OBJECT-TYPE SYNTAX Integer32 (0..MAX) 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 Aboba & Zorn Informational [Page 5] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of RADIUS Accounting-Request packets sent since client start-up. This does not include retransmissions." ::= { radiusAccServerEntry 5 } radiusAccClientRetransmissions OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of RADIUS Accounting-Request packets retransmitted to this RADIUS accounting server since client start-up. 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 total number of RADIUS packets received on the accounting port from this server since client start-up." ::= { radiusAccServerEntry 7 } radiusAccClientMalformedResponses OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of malformed RADIUS Accounting-Response packets received from this server since client start-up. 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 total number of RADIUS Accounting-Response packets which contained invalid authenticators received from this server since client start-up." ::= { radiusAccServerEntry 9 } radiusAccClientPendingRequests OBJECT-TYPE SYNTAX Gauge32 Aboba & Zorn Informational [Page 6] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 MAX-ACCESS read-only STATUS current DESCRIPTION "The total 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 total number of accounting timeouts to ths server since client startup. 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 total number of RADIUS packets of unknown type which were received from this server on the accounting port since client start-up." ::= { radiusAccServerEntry 12 } radiusAccClientPacketsDropped OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The total number of RADIUS packets which were received from this server on the accounting port and dropped for some other reason since client start-up." ::= { radiusAccServerEntry 13 } -- conformance information radiusAccClientMIBConformance OBJECT IDENTIFIER ::= { radiusAccClientMIB 2 } radiusAccClientMIBCompliances OBJECT IDENTIFIER ::= { radiusAccClientMIBConformance 1 } radiusAccClientMIBGroups OBJECT IDENTIFIER ::= { radiusAccClientMIBConformance 2 } Aboba & Zorn Informational [Page 7] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 -- 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 7. References [1] Harrington, D., Presuhn, R., and B. Wijnen, "An Architecture for Describing SNMP Management Frameworks", RFC 2271, Cabletron Sys- tems, Inc., BMC Software, Inc., IBM T. J. Watson Research, Jan- uary 1998. [2] Rose, M., and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based Internets", RFC 1155, Performance Systems International, Hughes LAN Systems, May 1990. [3] Rose, M., and K. McCloghrie, "Concise MIB Definitions", RFC 1212, Performance Systems International, Hughes LAN Systems, March Aboba & Zorn Informational [Page 8] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 1991. [4] M. Rose, "A Convention for Defining Traps for use with the SNMP", RFC 1215, Performance Systems International, March 1991. [5] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure of Management Information for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1902, SNMP Research,Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Services, January 1996. [6] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Textual Conventions for Version 2 of the Simple Network Management Proto- col (SNMPv2)", RFC 1903, SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Ser- vices, January 1996. [7] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Confor- mance Statements for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1904, SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Ser- vices, January 1996. [8] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Net- work Management Protocol", RFC 1157, SNMP Research, Performance Systems International, Performance Systems International, MIT Laboratory for Computer Science, May 1990. [9] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Introduc- tion to Community-based SNMPv2", RFC 1901, SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Services, 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, SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Services, January 1996. [11] Case, J., Harrington D., Presuhn R., and B. Wijnen, "Message Pro- cessing and Dispatching for the Simple Network Management Proto- col (SNMP)", RFC 2272, SNMP Research, Inc., Cabletron Systems, Inc., BMC Software, Inc., IBM T. J. Watson Research, January 1998. [12] Blumenthal, U., and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", RFC 2274, IBM T. J. Watson Research, January 1998. [13] Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for Version 2 of the Simple Network Management Proto- col (SNMPv2)", RFC 1905, SNMP Research, Inc., Cisco Systems, Inc., Dover Beach Consulting, Inc., International Network Ser- vices, January 16. Aboba & Zorn Informational [Page 9] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 [14] Levi, D., Meyer, P., and B. Stewart, "SNMPv3 Applications", RFC 2273, SNMP Research, Inc., Secure Computing Corporation, Cisco Systems, January 1998 [15] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", RFC 2275, IBM T. J. Watson Research, BMC Software, Inc., Cisco Systems, Inc., January 1998 [16] Rigney, C., "RADIUS Accounting", RFC 2139, April 1997. [17] "Information processing systems - Open Systems Interconnection - Specification of Abstract Syntax Notation One (ASN.1)", Interna- tional Organization for Standardization, International Standard 8824, December 1987. 8. 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 2274 [12] and the View-based Access Aboba & Zorn Informational [Page 10] INTERNET-DRAFT RADIUS Accounting Client MIB 11 November 1998 Control Model RFC 2275 [15] is recommended. Using these security fea- tures, 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. 9. Acknowledgments Thanks to Narendra Gidwani of Microsoft, Allan C. Rubens of MERIT, Carl Rigney of Livingston and Peter Heitman of American Internet Cor- poration for useful discussions of this problemspace. 10. 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 11. Expiration Date This memo is filed as , and expires May 1, 1999. Aboba & Zorn Informational [Page 11]