RFC2618
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.
Contents
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.
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.
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.
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.
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: [email protected]"
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
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.
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.
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.
Authors' Addresses
Bernard Aboba Microsoft Corporation One Microsoft Wy 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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