Configure Supported Cisco IOS SNMP Traps

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Updated:June 1, 2026
Document ID:13506

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Introduction

This document describes how to configure supported Cisco IOS® SNMP Traps.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

  • Knowledge of Cisco IOS command line interface (CLI)

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Conventions

Refer to the Cisco Technical Tips Conventions for more information on document conventions.

Background Information

When working with SNMP, it is recommended to limit the number of traps enabled on a Cisco device to prevent excessive traffic. For example, enabling all traps on a Remote Access Server with 64 dial-in lines would generate a trap for every connection and disconnection event, which can quickly overwhelm your monitoring system. Cisco IOS Software allows you to configure specific groups of traps to enable or disable, which helps manage trap volume effectively. There are two global configuration commands to configure SNMP traps into a Cisco IOS Software device:

snmp-server host host-addr [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}]
 community-string [udp-port port] [notification-type]

Issue the snmp-server host global configuration command to specify the recipient of an SNMP notification operation. Issue the no form of this command to remove the specified host.

snmp-server enable traps [notification-type] [notification-option]

Issue the snmp-server enable traps global configuration command to enable the router to send SNMP traps. Issue theno form of this command to disable SNMP notifications.

The types of traps can be specified in both commands. You must issue the snmp-server host command to define the Network Management Systems where traps are sent. You must specify the trap types if you do not want all traps sent. Issue multiple snmp-server enable traps commands, one for each of the trap types that you used in the snmp host command.

Note: Not all [notification-type] options are supported on both commands. For example, [notification-type] x25 and teletype (tty) are not used for snmp-server enable trap x25, and tty traps are enabled by default.

For example, issue these commands to make a Cisco IOS Software device report only configuration, Border Gateway Protocol (BGP), and tty traps to Network Management System 10.10.10.10:

snmp-server host 10.10.10.10 public config bgp tty 
snmp-server enable traps config 
snmp-server enable traps bgp

Note: Cisco IOS  Software Release 12.1(3)T was used to prepare this document. Using a different Cisco IOS Software release can result in variations in supported options, as feature availability can differ across versions. When you use a Cisco IOS Software release later than 12.1(3)T, additional [notification-type] options can be supported. You can find a current list of all supported Cisco IOS Software Simple Network Management Protocol (SNMP) trap Object Identifiers (OIDs) in this document.

Cisco devices that run the standard Cisco IOS Software (routers, Asynchronous Transfer Mode (ATM) switches, and Remote Access Servers) can generate many SNMP traps.

Commands

The snmp-server-host Command

Issue the snmp-server host global configuration command to specify the recipient of an SNMP notification operation. Issue the no form command to remove the specified host.

snmp-server host host-addr [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] 
community-string [udp-port port] [notification-type] 
no snmp-server host host [traps | informs]

Syntax Description

host-addr The name or Internet address of the host (the targeted recipient).
traps (Optional)  Send SNMP traps to this host; this is the default. 
informs (Optional) Send SNMP informs to this host.
version (Optional) The version of the SNMP used to send the traps. Version 3 is the most secure model, as this model allows packet encryption with the priv keyword. If you use the version keyword, you must specify one of these options:
  • 1 — SNMPv1. This option is not available with informs.
  • 2c — SNMPv2C
  • 3 — SNMPv3. These three optional keywords can be after the version 3 keyword:
    • auth (Optional) Enables Message Digest 5 (MD5) and Secure Hash Algorithm (SHA) packet authentication.
    • noauth (Default) The noAuthNoPriv security level. This is the default if the [auth | noauth | priv] keyword choice is not specified.
    • priv (Optional) Enables Data Encryption Standard (DES) packet encryption (also called "privacy").
community-string The password-like community string sent with the notification operation. Though you can set this string with the snmp-server host command by itself, Cisco recommends that you define this string with the snmp-server community command before you issue the snmp-server host command.
udp-portport User Datagram Protocol (UDP) port of the host to use; the default is 162.
notification-type (Optional) The type of notification to be sent to the host. If no type is specified, all notifications are sent. The notification type can be one or more of these keywords:
  • aaa-server — Sends AAA notifications.
  • bgp — Sends Border Gateway Protocol (BGP) state change notifications.
  • bstun — Sends Block Serial Tunneling (BSTUN) notifications.
  • calltracker — Sends CallTracker notifications.
  • config — Sends configuration notifications.
  • dlsw — Sends data-link switching (DLSw) notifications.
  • ds0-busyout — Sends ds0-busyout notifications.
  • ds1-loopback — Sends ds1-loopback notifications.
  • dspu — Sends downstream physical unit (DSPU) notifications.
  • dsp — Sends digital signal processing (DSP) notifications.
  • entity — Sends Entity Management Information Base (MIB) modification notifications.
  • envmon — Sends Cisco enterprise-specific environmental monitor notifications when an environmental threshold is exceeded.
  • frame-relay — Sends Frame Relay notifications.
  • hsrp — Sends Hot Standby Router Protocol (HSRP) notifications.
  • isdn — Sends Integrated Services Digital Network (ISDN) notifications.
  • msdp — Sends Multicast Source Discovery Protocol (MSDP) notifications.
  • llc2 — Sends Logical Link Control, type 2 (LLC2) notifications.
  • repeater  — Sends standard repeater (hub) notifications.
  • rsrb — Sends remote source-route bridging (RSRB) notifications.
  • rsvp — Sends Resource Reservation Protocol (RSVP) notifications.
  • rtr — Sends SA Agent (RTR) notifications.
  • sdlc — Sends Synchronous Data Link Control (SDLC) notifications.
  • snmp — Sends Simple Network Management Protocol (SNMP) notifications (as defined in RFC 1157).
  • stun — Sends serial tunnel (STUN) notifications.
  • syslog — Sends error message notifications (Cisco Syslog MIB). Specify the level of messages to be sent with the  logging history level   command.
  • tty — Sends Cisco enterprise-specific notifications when a Transmission Control Protocol (TCP) connection closes.
  • voice — Sends voice notifications.
  • x25 — Sends X.25 event notifications.
  • xgcp — Sends External Media Gateway Control Protocol (XGCP) notifications.

Defaults

The snmp-server host command is disabled by default and no notifications are sent.

If you enter this command with no keywords, the default is to send all trap types to the host.

No informs are sent to this host. If no version keyword is present, the default is version 1. The no snmp-server host command with no keywords disables traps, but not informs to the host. Issue the no snmp-server host informs command to disable informs.

Note: If the community-string is not defined with the snmp-server community command before you use this command, the default form of the snmp-server community command is automatically inserted into the configuration. The password (community-string) is used for the automatic configuration of the snmp-server community, which is the same as the specified snmp-server host command. This is the default behavior for Cisco IOS Software Release 12.0(3) and later.

Command Modes

Global Configuration - Command History

Cisco IOS Software Release Modification
10.0 Command introduced.
12.0(3)T These keywords have been added:
  • version 3 [auth | noauth | priv]
  • hsrp

Use Guidelines

SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver does not send acknowledgments when this device receives traps. The sender cannot determine if the traps were received. However, an SNMP entity that receives an inform request acknowledges the message with an SNMP response protocol data unit (PDU). If the sender never receives the response, the inform request can be sent again. Therefore, informs are more likely to reach their intended destination.

However, informs consume more resources in the agent and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received, or the request times out. Traps are sent only once, while an inform can be retried several times. The retries increase traffic and contribute to a higher overhead on the network.

If you do not enter an snmp-server host command, no notifications are sent. To configure the router to send SNMP notifications, you must enter at least one snmp-server host command. If you enter the command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must issue a separate snmp-server host command for each host. You can specify multiple notification types in the command for each host.

When multiple snmp-server host commands are given for the same host and notification (trap or inform), each command overwrites the previous command. Only the last snmp-server host command is taken into account. For example, if you enter an snmp-server host inform command for a host and then enter another snmp-server host inform command for the same host, the second command replaces the first.

The snmp-server host command is used in conjunction with the snmp-server enable command. Issue the snmp-server enable command to specify which SNMP notifications are sent globally. In order for a host to receive the most notifications, at least one snmp-server enable command and the snmp-server host command for that host must be enabled.

However, some notification types cannot be controlled with the snmp-server enable command. For example, some notification types are always enabled. Other notification types are enabled by a different command. For example, the linkUpDown notifications are controlled by the snmp trap link-status command. These notification types do not require an snmp-server enable command.

The availability of a notification-type option depends on the router type and Cisco IOS software features supported on the router. For example, the envmon notification-type is available only if the environmental monitor is part of the system.

Configure Informs

Complete these steps to send an inform:

  1. Configure a remote engine ID.

  2. Configure a remote user.

  3. Configure a group on a remote device.

  4. Enable traps on the remote device.

  5. Enable the SNMP manager.

Examples

To configure a unique SNMP community string for traps, but you want to prevent SNMP polling access with this string, the configuration must include an access-list. In this example, the community string is named comaccess, and the access list is numbered 10:

snmp-server community comaccess ro 10
snmp-server host 172.20.2.160 comaccess
access-list 10 deny any

This example sends the SNMP traps to the host specified by the name myhost.cisco.com. The community string is defined as comaccess:

snmp-server enable traps
snmp-server host myhost.cisco.com comaccess snmp

This example sends the SNMP and Cisco environmental monitor enterprise-specific traps to address 172.30.2.160:

snmp-server enable traps
snmp-server host 172.30.2.160 public snmp envmon

This example enables the router to send all traps to the host myhost.cisco.com with the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com public

This example does not send traps to any host. The BGP traps are enabled for all hosts, but only the ISDN traps are enabled to send to a host.

snmp-server enable traps bgp
snmp-server host bob public isdn

This example enables the router to send all inform requests to the host myhost.cisco.com with the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com informs version

This example sends HSRP SNMPv2c traps to the host specified by the name myhost.cisco.com. The community string is defined as public.

snmp-server enable traps
snmp-server host myhost.cisco.com traps version 2c public hsrp

The snmp-server enable traps Command

Use the snmp-server enable traps global configuration command to enable the router to send SNMP traps. Use the no form of this command to disable SNMP notifications.

snmp-server enable traps [notification-type] [notification-option] 

no snmp-server enable traps [notification-type] [notification-option]

Syntax Description

notification-type

(Optional): The type of notification to enable. If no type is specified, all notifications are sent (that includes the envmon and repeaternotifications). The notification type can be one of these keywords:

  • aaa-server — Sends AAA Server notifications. This keyword is added since Cisco IOS Software Release 12.1(3)T for Cisco AS5300 and AS5800 platforms only. This is from the CISCO-AAA-SERVER-MIB and the notifications are: enterprise 1.3.6.1.4.1.9.10.56.2 1 casServerStateChange
  • bgp — Sends Border Gateway Protocol (BGP) state change notifications. This is from the BGP4-MIB, and the notifications are: enterprise 1.3.6.1.2.1.15.7 1 bgpEstablished 2 bgpBackwardTransition.
  • calltracker — Sends a notification when a new active call entry is created in the cctActiveTable or a new history call entry is created in the cctHistoryTable This is from the CISCO-CALL-TRACKER-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.163.2 1 cctCallSetupNotification 2 cctCallTerminateNotification.
  • config — Sends configuration notifications. This is from the CISCO-CONFIG-MAN-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.43.2 1 ciscoConfigManEvent.
  • dial — Sends a notification when a successful call clears, a failed call attempt is determined to have ultimately failed, or whenever a call setup message is received or sent. This is from the DIAL-CONTROL-MIB, and the notifications are: enterprise 1.3.6.1.2.1.10.21.2 1 dialCtlPeerCallInformation 2 dialCtlPeerCallSetup.
  • dlsw — Sends notifications from DLSw agents When the dlswkeyword is used, you can specify anotification-optionvalue. This is from the CISCO-DLSW-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.10.9.1.7 1 ciscoDlswTrapTConnPartnerReject 2 ciscoDlswTrapTConnProtViolation 3 ciscoDlswTrapTConnUp 4 ciscoDlswTrapTConnDown 5 ciscoDlswTrapCircuitUp 6 ciscoDlswTrapCircuitDown.
  • ds0-busyout — Sends a notification when the busyout of a DS0 interface changes state. This keyword is added since Cisco IOS Software Release 12.1(3)T for the Cisco AS5300 platform only. This is from the CISCO-POP-MGMT-MIB, and the notification is: enterprise 1.3.6.1.4.1.9.10.19.2 1 cpmDS0BusyoutNotification.
  • ds1-loopback — Sends a notification whenever the DS1 interface goes into loopback mode. This keyword is added since Cisco IOS Software Release 12.1(3)T for the Cisco AS5300 platform only. This is from the CISCO-POP-MGMT-MIB, and the notification is: enterprise 1.3.6.1.4.1.9.10.19.2 2 cpmDS1LoopbackNotification.
  • dspu — Sends a notification when the operational state of the physical unit (PU) or the logical unit (LU) changes or activation failure is detected. This is from the CISCO-DSPU-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.24.1.4.4 1newdspuPuStateChangeTrap 2 newdspuPuActivationFailureTrap enterprise 1.3.6.1.4.1.9.9.24.1.5.3 1 newdspuLuStateChangeTrap 2 dspuLuActivationFailureTrap.
  • dsp — Sends a notification when the DSP card goes up or down. This is from the CISCO-DSP-MGMT-MIB, and the notification is: enterprise 1.3.6.1.4.1.9.9.86.2 1 cdspMIBCardStateNotification.
  • entity — Sends Entity MIB modification notifications. This is from the ENTITY-MIB, and the notifications are: enterprise 1.3.6.1.2.1.47.2 1 entConfigChange.
  • envmon — Sends Cisco enterprise-specific environmental monitoring notifications when an environmental threshold is exceeded. When theenvmonkeyword is used, you can specify anotification-optionvalue. This is from the CISCO-ENVMON-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.13.3 1 ciscoEnvMonShutdownNotification 2 ciscoEnvMonVoltageNotification 3 ciscoEnvMonTemperatureNotification 4 ciscoEnvMonFanNotification 5 ciscoEnvMonRedundantSupplyNotification.
  • frame-relay — Sends Frame Relay notifications. This is from the RFC1315-MIB, and the notifications are: enterprise 1.3.6.1.2.1.10.32 1 frDLCIStatusChange.
  • hsrp — Sends Hot Standby Router Protocol (HSRP) notifications. This feature is supported since Cisco IOS Software Release 12.0(3)T. This is from the CISCO-HSRP-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.106.2 1 cHsrpStateChange.
  • isdn — Sends ISDN notifications. When the isdnkeyword is used, you can specify anotification-optionvalue. This is from the CISCO-ISDN-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.26.2 1 demandNbrCallInformation 2 demandNbrCallDetails 3 demandNbrLayer2Change [supported since Cisco IOS Software Release 12.1(1)T ] 4 demandNbrCNANotification [supported since Cisco IOS Software Release 12.1(5)T ] This is from the CISCO-ISDNU-IF-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.18.2 1 ciuIfLoopStatusNotification.
  • msdp — Sends Multicast Source Discovery Protocol (MSDP) notifications. This is from the MSDP-MIB, and the notifications are: enterprise 1.3.6.1.3.92.1.1.7 1 msdpEstablished 2 msdpBackwardTransition.
  • repeater  — Sends Ethernet hubrepeaternotifications. When the repeater keyword is selected, you can specify a notification-option value. This is from the CISCO-REPEATER-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.22.3 1 ciscoRptrIllegalSrcAddrTrap.
  • rsvp — Sends Resource Reservation Protocol (RSVP) notifications. This feature is supported since Cisco IOS Software Release 12.0(2)T. This is from the RSVP-MIB, and the notifications are: enterprise 1.3.6.1.3.71.2 1 newFlow 2 lostFlow.
  • rtr — Sends Service Assurance Agent RTR (RTR) notifications. This is from the CISCO-RTTMON-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.42.2 1 rttMonConnectionChangeNotification 2 rttMonTimeoutNotification 3 rttMonThresholdNotification 4 rttMonVerifyErrorNotification.
  • snmp — Sends Simple Network Management Protocol (SNMP) notifications. When thesnmpkeyword is used, you can specify a notification-option value. This is from the CISCO-GENERAL-TRAPS, and the notifications are: enterprise 1.3.6.1.2.1.11 0 coldStart 2 linkDown 3 linkUp 4 authenticationFailure 5 egpNeighborLoss enterprise 1.3.6.1.4.1.9 0 reload.

    Note: This trap is controlled by the notification-type "tty": 1 tcpConnectionClose.

  • syslog— Sends error message notifications (Cisco Syslog MIB). Specify the level of messages to be sent with the logging history level command. This is from the CISCO-SYSLOG-MIB, and the notifications are: enterprise 1.3.6.1.4.1.9.9.41.2 1 clogMessageGenerated.
  • voice — Sends poor quality of voice notifications. This is from the CISCO-VOICE-DIAL-CONTROL-MIBSMI, and the notifications are: enterprise 1.3.6.1.4.1.9.9.63.2 1 cvdcPoorQoVNotification.
  • xgcp — Sends External Media Gateway Control Protocol (XGCP) notifications. This is from the XGCP-MOB, and the notifications are: enterprise 1.3.6.1.3.90.2 1 xgcpUpDownNotification.
notification-option (Optional)
  • dlsw [circuit | tconn] — When thedlswkeyword is used, you can specify the specific notification type to enable or disable. If no keyword is used, all DLSw notification types are enabled. The option can be one or more of these keywords:
    • circuit — Enables DLSw circuit traps.
    • tconn — Enables DLSw peer transport connection traps.
  • envmon [voltage | shutdown | supply | fan | temperature] — When theenvmonkeyword is used, you can enable a specific environmental notification type or accept all notification types from the environmental monitor system. If no option is specified, all environmental notifications are enabled. The option can be one or more of these keywords:voltage,shutdown,supply,fan, andtemperature.
  • isdn [call-information | isdn u-interface | chan-not-avail | layer2] — When the isdn keyword is used, you can specify the call-information keyword to enable an SNMP ISDN call information notification for the ISDN MIB subsystem, or you can specify the isdn u-interface keyword to enable an SNMP ISDN U interface notification for the ISDN U interface MIB subsystem.
  • repeater [health | reset] — When the repeater keyword is used, you can specify the repeater option. If no option is specified, all repeater notifications are enabled. The option can be one or more of these keywords: health—Enables Internet Engineering Task Force (IETF) Repeater Hub MIB (RFC 1516) health notification. Reset—Enables IETF Repeater Hub MIB (RFC 1516) reset notification.
    • health— Enables the Internet Engineering Task Force (IETF) Repeater Hub MIB (RFC 1516) health notification.
    • reset — Enables the IETF Repeater Hub MIB (RFC 1516) reset notification.
  • snmp [authentication | linkup | linkdown | coldstart] keywords linkup | linkdown | coldstart added since Cisco IOS Software Release 12.1(3)T. When thesnmp keyword is used, you can specify the specific notification type to enable or disable. If no keyword is used, all SNMP notification types are enabled (or disabled, if the no form is used). The notification types available are:
    • authentication — Controls the distribution of SNMP authentication failure notifications. An authenticationFailure(4) trap signifies that the sending protocol entity is the addressee of a protocol message that is not properly authenticated.
    • linkup — Controls the sending of SNMP linkup notifications. A linkUp(3) trap signifies that the sending protocol entity recognizes that one of the communication links represented in the configuration of the agent has come up.
    • linkdown — Controls the how SNMP linkdown notifications are sent. A linkDown(2) trap signifies that the sending protocol entity recognizes a failure in one of the communication links represented in the configuration of the agent.
    • coldstart — Controls the sending of SNMP coldstart notifications. A coldStart(0) trap signifies that the sending protocol entity is reinitializes itself such that the configuration of the agent or the protocol entity implementation can be altered.

Defaults

SNMP notifications are disabled.

If you enter this command with no notification-type keywords, the default is to enable all notification types controlled by this command.

Command Modes

Global Configuration - Command History

Cisco IOS Software Release Modification
11.1 This command was introduced.
12.0(2)T Thersvpkeyword was added.
12.0(3)T The hsrp keyword was added.
12.1(3)T These keywords have been added to thesnmp-server enable traps snmp form of this command:
  • linkup
  • linkdown
  • coldstart
These notification type keywords have been added for the Cisco AS5300 platform only:
  • ds0-busyout
  • isdn chan-not-avail
  • modem-health
  • ds1-loopback
This notification type keyword has been added for the Cisco AS5300 and AS5800 platforms only:
  • aaa-server

Use Guidelines

The snmp-server enable traps snmp [ linkup] [linkdown] form of this command replaces the snmp trap link-status interface configuration mode command.

The no form of the snmp-server enable traps command is useful to disable notifications that generate a large amount of unnecessary noise on your network.

SNMP notifications can be sent as traps or inform requests. This command enables both traps and inform requests for the specified notification types.

If you do not enter an snmp-server enable traps command, no notifications controlled by this command are sent. To configure the router to send these SNMP notifications, you must enter at least one snmp-server enable traps command. If you enter the command with no keywords, all notification types are enabled. If you enter the command with a keyword, only the notification type related to that keyword is enabled. To enable multiple types of notifications, you must issue a separate snmp-server enable traps command for each notification type and notification option.

The snmp-server enable traps command is used in conjunction with the snmp-server host command. Issue the snmp-server host command to specify which host or hosts receive SNMP notifications. To send notifications, you must configure at least one snmp-server host command.

For a host to receive a notification controlled by this command, both the snmp-server enable traps command and the snmp-server host command for that host must be enabled. If the notification type is not controlled by this command, only the appropriate snmp-server host command must be enabled.

The notification types used in this command all have an associated MIB object that allows them to be enabled or disabled (for example, HSRP traps are defined with the HSRP MIB, repeater traps are defined with the Repeater Hub MIB, and so on). Not all of the notification types available in the snmp-server host command have notificationEnable MIB objects, so, some of these cannot be controlled with the snmp-server enable command.

Related Information

Revision History

Revision Publish Date Comments
4.0
01-Jun-2026
Updated spelling, grammar, sentence structure, etc.
3.0
18-Dec-2023
Recertification
1.0
10-Dec-2001
Initial Release
TAC Authored

Contributed by Cisco Engineers

  • Marin Grabovschi
    Cisco Technical Consulting Engineer

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