Network Working Group B. Aboba

Network Working Group B. Aboba
Request for Comments: 2620 G. Zorn
Category: Informational Microsoft
June 1999

RADIUS Accounting Client MIB

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:

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

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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].

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 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.

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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: [email protected]"
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 }

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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 }

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::= { radiusAccServerTable 1 }

RadiusAccServerEntry ::= SEQUENCE {
radiusAccServerIndex Integer32,
radiusAccServerAddress IpAddress,
radiusAccClientServerPortNumber Integer32,
radiusAccClientRoundTripTime TimeTicks,
radiusAccClientRequests Counter32,
radiusAccClientRetransmissions Counter32,
radiusAccClientResponses Counter32,
radiusAccClientMalformedResponses Counter32,
radiusAccClientBadAuthenticators Counter32,
radiusAccClientPendingRequests Gauge32,
radiusAccClientTimeouts Counter32,
radiusAccClientUnknownTypes Counter32,
radiusAccClientPacketsDropped Counter32
}

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

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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

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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

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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

radiusAccClientMIBConformance
OBJECT IDENTIFIER ::= { radiusAccClientMIB 2 }
radiusAccClientMIBCompliances
OBJECT IDENTIFIER ::= { radiusAccClientMIBConformance 1 }
radiusAccClientMIBGroups
OBJECT IDENTIFIER ::= { radiusAccClientMIBConformance 2 }

-- 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,

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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,
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.

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[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:

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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.

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8. Authors' Addresses

Bernard Aboba
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052

Phone: 425-936-6605
EMail: [email protected]

Glen Zorn
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052

Phone: 425-703-1559
EMail: [email protected]

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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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