SNMP-MPD-MIB

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Organization: SNMPv3 Working Group

Last Updated: 2002-10-14

Category: SNMP Framework

Description: Defines managed objects for managing the SNMP Message Processing and Dispatching subsystem.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring SNMP-MPD-MIB with a free 30-day trial of IPNetwork Monitor.

What Is SNMP-MPD-MIB?

SNMP-MPD-MIB is the standard IETF MIB (RFC 3412) for the SNMPv3 Message Processing and Dispatching (MPD) subsystem, the layer of the SNMP engine responsible for routing incoming/outgoing messages to the correct security and access-control modules. It exposes counters for protocol-level anomalies the MPD subsystem detects, including unknown security models, invalid messages, and PDUs with no matching handler registered, rather than any application or hardware data. Its monitoring value is entirely about the health of the SNMP management plane itself: a rising invalid-message or unknown-handler counter signals misconfigured managers, version mismatches, or a security-model problem that's silently breaking manageability of the device, important to catch before it's mistaken for the device itself being unresponsive. It is a core component of the standard SNMPv3 architecture (RFC 3411 family) and works alongside the USM/VACM MIBs that handle the security and access-control decisions the MPD dispatches to. It is present on virtually any SNMPv3-capable agent as part of the standard engine, most useful when diagnosing intermittent manageability issues across a fleet of devices. Engineers implementing or auditing this functionality typically reference the SNMP-MPD-MIB RFC/standard documentation for the authoritative specification.

IPNetwork Monitor allows you to monitor SNMP objects defined in SNMP-MPD-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

vendor-neutral, standards-based MIB (RFC 3412), not tied to a specific manufacturer
any SNMPv3-capable device/agent

Monitoring Examples

An operator would trend snmpUnknownSecurityModels and snmpInvalidMsgs under snmpMPDStats to detect a manager sending requests with the wrong SNMPv3 security model or corrupted messages, and check snmpUnknownPDUHandlers to catch requests aimed at an unregistered application. A sudden spike in any of these three counters on one device, while others in the fleet stay at zero, usually points to a misconfigured monitoring poller rather than a device-side fault.

What Can Be Monitored

unknown security model count
invalid message count
unknown PDU handler count
overall MPD subsystem error statistics

Imported Objects

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
MODULE-IDENTITY
OBJECT-TYPE
snmpModules

How to Use in IPNetwork Monitor

Example using snmpUnknownSecurityModels OID:

Select a device implementing SNMP-MPD-MIB as the target host to create a monitor — the SNMP service should be up and running on it. Click New Monitor, then check SNMP Custom on the Favorites tab, click Next, and confirm the host. On the next page, click Select... to open the built-in SNMP MIB Browser and type snmpUnknownSecurityModels into the Find box to locate it in the OID tree, then select it and click OK. The total number of packets received by the SNMP engine which were dropped because they referenced a securityModel that was not known to or supported by the SNMP engine. On the monitor's Main parameters page you can set the target's SNMP port (default 161), credentials, polling interval, and other settings — see the SNMP Monitor help for details. On the State conditions and Alerting tabs, configure when the monitor should change state and trigger an alert; since this is a Counter32-type OID, Value bounds is the most useful condition here — trigger an alert if the counter increases between polls, since a rising count of errors, failures, or discards often points to a real underlying problem. Click Finish to create the monitor; you can adjust any parameter later.

OIDs

OID symbolic	OID numeric	Type	Access	Description
snmpMPDMIB	1.3.6.1.6.3.11			The MIB for Message Processing and Dispatching Copyright (C) The Internet Society (2002). This version of this MIB module is part of RFC 3412; see the RFC itself for full legal notices.
snmpMPDAdmin	1.3.6.1.6.3.11.1
snmpMPDMIBObjects	1.3.6.1.6.3.11.2
snmpMPDStats	1.3.6.1.6.3.11.2.1
C32 snmpUnknownSecurityModelsEx	1.3.6.1.6.3.11.2.1.1	Counter32	read-only	The total number of packets received by the SNMP engine which were dropped because they referenced a securityModel that was not known to or supported by the SNMP engine.
C32 snmpInvalidMsgs	1.3.6.1.6.3.11.2.1.2	Counter32	read-only	The total number of packets received by the SNMP engine which were dropped because there were invalid or inconsistent components in the SNMP message.
C32 snmpUnknownPDUHandlers	1.3.6.1.6.3.11.2.1.3	Counter32	read-only	The total number of packets received by the SNMP engine which were dropped because the PDU contained in the packet could not be passed to an application responsible for handling the pduType, e.g. no SNMP application had registered for the proper combination of the contextEngineID and the pduType.
snmpMPDMIBConformance	1.3.6.1.6.3.11.3
snmpMPDMIBCompliances	1.3.6.1.6.3.11.3.1
snmpMPDCompliance	1.3.6.1.6.3.11.3.1.1			The compliance statement for SNMP entities which implement the SNMP-MPD-MIB.
snmpMPDMIBGroups	1.3.6.1.6.3.11.3.2
snmpMPDGroup	1.3.6.1.6.3.11.3.2.1			A collection of objects providing for remote monitoring of the SNMP Message Processing and Dispatching process.

RFC description

Provides message processing and dispatching statistics for SNMPv3 protocol operations.

Start monitoring vendor-neutral, standards-based MIB (RFC 3412), any SNMPv3-capable device/agent (message-processing/dispatch error counters) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

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