Configuring SNMP

This chapter describes how to configure the SNMP feature on Cisco NX-OS devices.

This chapter includes the following sections:

Information About SNMP

The Simple Network Management Protocol (SNMP) is an application-layer protocol that provides a message format for communication between SNMP managers and agents. SNMP provides a standardized framework and a common language used for the monitoring and management of devices in a network.

This section includes the following topics:

SNMP Functional Overview

The SNMP framework consists of three parts:

  • An SNMP manager—The system used to control and monitor the activities of network devices using SNMP.
  • An SNMP agent—The software component within the managed device that maintains the data for the device and reports these data, as needed, to managing systems. Cisco NX-OS supports the agent and MIB. To enable the SNMP agent, you must define the relationship between the manager and the agent.
  • A managed information base (MIB)—The collection of managed objects on the SNMP agent.

SNMP is defined in RFCs 3411 to 3418.

Cisco NX-OS supports SNMPv1, SNMPv2c, and SNMPv3. Both SNMPv1 and SNMPv2c use a community-based form of security.

Cisco NX-OS supports SNMP over IPv6.

SNMP Notifications

A key feature of SNMP is the ability to generate notifications from an SNMP agent. These notifications do not require that requests be sent from the SNMP manager. Notifications can indicate improper user authentication, restarts, the closing of a connection, loss of a connection to a neighbor router, or other significant events.

Cisco NX-OS generates SNMP notifications as either traps or informs. A trap is an asynchronous, unacknowledged message sent from the agent to the SNMP managers listed in the host receiver table (see the “Configuring SNMP Notification Receivers with VRFs” section). Informs are asynchronous messages sent from the SNMP agent to the SNMP manager which the manager must acknowledge receipt of.

Traps are less reliable than informs because the SNMP manager does not send any acknowledgment when it receives a trap. Cisco NX-OS cannot determine if the trap was received. An SNMP manager that receives an inform request acknowledges the message with an SNMP response protocol data unit (PDU). If Cisco NX-OS never receives a response, it can send the inform request again.

You can configure Cisco NX-OS to send notifications to multiple host receivers. See the “Configuring SNMP Notification Receivers” section for more information about host receivers.

Table 13-1 lists the SNMP traps that are enabled by default.

Table 13-1 SNMP Traps Enabled By Default

Trap Type
Description

generic

: coldStart

generic

: warmStart

entity

: entity_mib_change

entity

: entity_module_status_change

entity

: entity_power_status_change

entity

: entity_module_inserted

entity

: entity_module_removed

entity

: entity_unrecognised_module

entity

: entity_fan_status_change

entity

: entity_power_out_change

link

: linkDown

link

: linkUp

link

: extended-linkDown

link

: extended-linkUp

link

: cieLinkDown

link

: cieLinkUp

link

: delayed-link-state-change

rf

: redundancy_framework

license

: notify-license-expiry

license

: notify-no-license-for-feature

license

: notify-licensefile-missing

license

: notify-license-expiry-warning

upgrade

: UpgradeOpNotifyOnCompletion

upgrade

: UpgradeJobStatusNotify

rmon

: risingAlarm

rmon

: fallingAlarm

rmon

: hcRisingAlarm

rmon

: hcFallingAlarm

entity

: entity_sensor

SNMPv3

SNMPv3 provides secure access to devices by a combination of authenticating and encrypting frames over the network. The security features provided in SNMPv3 are as follows:

  • Message integrity—Ensures that a packet has not been tampered with while it was in-transit.
  • Authentication—Determines that the message is from a valid source.
  • Encryption—Scrambles the packet contents to prevent it from being seen by unauthorized sources.

SNMPv3 provides for both security models and security levels. A security model is an authentication strategy that is set up for a user and the role in which the user resides. A security level is the permitted level of security within a security model. A combination of a security model and a security level determines which security mechanism is employed when handling an SNMP packet.

This section includes the following topics:

Security Models and Levels for SNMPv1, v2, v3

The security level determines if an SNMP message needs to be protected from disclosure and if the message needs to be authenticated. The various security levels that exist within a security model are as follows:

  • noAuthNoPriv—Security level that does not provide authentication or encryption.
  • authNoPriv—Security level that provides authentication but does not provide encryption.
  • authPriv—Security level that provides both authentication and encryption.

Three security models are available: SNMPv1, SNMPv2c, and SNMPv3. The security model combined with the security level determine the security mechanism applied when the SNMP message is processed.

Table 13-2 identifies what the combinations of security models and levels mean.

 

Table 13-2 SNMP Security Models and Levels
Model
Level
Authentication
Encryption
What Happens

v1

noAuthNoPriv

Community string

No

Uses a community string match for authentication.

v2c

noAuthNoPriv

Community string

No

Uses a community string match for authentication.

v3

noAuthNoPriv

Username

No

Uses a username match for authentication.

v3

authNoPriv

HMAC-MD5 or HMAC-SHA

No

Provides authentication based on the Hash-Based Message Authentication Code (HMAC) Message Digest 5 (MD5) algorithm or the HMAC Secure Hash Algorithm (SHA).

v3

authPriv

HMAC-MD5 or HMAC-SHA

DES

AES-128

Provides authentication based on the HMAC-MD5 or HMAC-SHA algorithms. By default, the switch provides Data Encryption Standard (DES) 56-bit encryption in addition to authentication based on the Cipher Block Chaining (CBC) DES (DES-56) standard. The switch also provides an option to use a 128-bit AES algorithm for privacy.

User-Based Security Model

The SNMPv3 User-Based Security Model (USM) refers to SNMP message-level security and offers the following services:

  • Message integrity—Ensures that messages have not been altered or destroyed in an unauthorized manner and that data sequences have not been altered to an extent greater than can occur nonmaliciously.
  • Message origin authentication—Ensures that the claimed identity of the user on whose behalf received data was originated is confirmed.
  • Message confidentiality—Ensures that information is not made available or disclosed to unauthorized individuals, entities, or processes.

SNMPv3 authorizes management operations only by configured users and encrypts SNMP messages.

Cisco NX-OS uses two authentication protocols for SNMPv3:

  • HMAC-MD5-96 authentication protocol
  • HMAC-SHA-96 authentication protocol

Cisco NX-OS uses Advanced Encryption Standard (AES) as one of the privacy protocols for SNMPv3 message encryption and conforms with RFC 3826.

The priv option offers a choice of DES or 128-bit AES encryption for SNMP security encryption. The priv option and the aes-128 token indicate that this privacy password is for generating a 128-bit AES key.The AES priv password can have a minimum of eight characters. If the passphrases are specified in clear text, you can specify a maximum of 64 case-sensitive alphanumeric characters. If you use the localized key, you can specify a maximum of 130 characters.

Note For an SNMPv3 operation that uses the external AAA server, you must use AES for the privacy protocol in the user configuration on the external AAA server.

CLI and SNMP User Synchronization

SNMPv3 user management can be centralized at the Access Authentication and Accounting (AAA) server level. This centralized user management allows the SNMP agent in Cisco NX-OS to leverage the user authentication service of the AAA server. Once user authentication is verified, the SNMP PDUs are processed further. Additionally, the AAA server is also used to store user group names. SNMP uses the group names to apply the access/role policy that is locally available in the switch.

Any configuration changes made to the user group, role, or password results in database synchronization for both SNMP and AAA.

Cisco NX-OS synchronizes user configuration in the following ways:

  • The authentication passphrase specified in the snmp-server user command becomes the password for the CLI user.
  • The password specified in the username command becomes the authentication and privacy passphrases for the SNMP user.
  • If you create or delete a user using either SNMP or the CLI, the user is created or deleted for both SNMP and the CLI.
  • User-role mapping changes are synchronized in SNMP and the CLI.
  • Role changes (deletions or modifications) from the CLI are synchronized to SNMP.

Note When you configure a passphrase/password in localized key/encrypted format, Cisco NX-OS does not synchronize the user information (password, roles, and so on).

Cisco NX-OS holds the synchronized user configuration for 60 minutes by default. See the “Modifying the AAA Synchronization Time” section for information on how to modify this default value.

Group-Based SNMP Access

Note Because group is a standard SNMP term used industry-wide, we refer to role(s) as group(s) in this SNMP section.

SNMP access rights are organized by groups. Each group in SNMP is similar to a role through the CLI. Each group is defined with read access or read-write access.

You can begin communicating with the agent once your username is created, your roles are set up by your administrator, and you are added to the roles.

SNMP and Embedded Event Manager

The Embedded Event Manager (EEM) feature monitors events, including SNMP MIB objects, and triggers an action based on these events. One of the actions could be to send an SNMP notification. EEM sends the cEventMgrPolicyEvent of CISCO-EMBEDDED-EVENT-MGR-MIB as the SNMP notification.

See Chapter 16, “Configuring the Embedded Event Manager” for more information about EEM.

Multiple Instance Support

A device can support multiple instances of a logical network entity, such as protocol instances or VRFs. Most existing MIBs cannot distinguish between these multiple logical network entities. For example, the original OSPF-MIB assumes a single protocol instance on a device, but you can now configure multiple OSPF instances on a device.

SNMPv3 uses contexts to distinguish between these multiple instances. An SNMP context is a collection of management information you can access through the SNMP agent. A device can support multiple contexts for different logical network entities. An SNMP context allows the SNMP manager to access one of the multiple instances of a MIB module supported on the device for the different logical network entities.

Cisco NX-OS supports the CISCO-CONTEXT-MAPPING-MIB to map between SNMP contexts and logical network entities. You can associate an SNMP context to a VRF, protocol instance, or topology.

SNMPv3 supports contexts with the contextName field of the SNMPv3 PDU. You can map this contextName field to a particular protocol instance or VRF.

For SNMPv2c, you can map the SNMP community to a context using the snmpCommunityContextName MIB object in the SNMP-COMMUNITY-MIB (RFC 3584). You can then map this snmpCommunityContextName to a particular protocol instance or VRF using the CISCO-CONTEXT-MAPPING-MIB or the CLI.

To map an SNMP context to a logical network entity, follow these steps:

Step 1 Create the SNMPv3 context.

Step 2 Determine the logical network entity instance.

Step 3 Map the SNMPv3 context to a logical network entity.

Step 4 Optionally, map the SNMPv3 context to an SNMPv2c community.

 

For more information, see the “Configuring the Context to Network Entity Mapping” section.

High Availability

Cisco NX-OS supports stateless restarts for SNMP. After a reboot or supervisor switchover, Cisco NX-OS applies the running configuration.

Virtualization Support

Cisco NX-OS supports one instance of the SNMP per virtual device context (VDC). By default, Cisco NX-OS places you in the default VDC. For more information, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 5.x .

SNMP supports multiple MIB module instances and maps them to logical network entities. For more information, see the “Multiple Instance Support” section.

SNMP is also VRF aware. You can configure SNMP to use a particular VRF to reach the SNMP notification host receiver. You can also configure SNMP to filter notifications to an SNMP host receiver based on the VRF where the notification occurred. For more information, see the “Configuring SNMP Notification Receivers with VRFs” section.

Licensing Requirements for SNMP

 

Product
License Requirement

Cisco NX-OS

SNMP requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide .

Prerequisites for SNMP

SNMP has the following prerequisites:

  • If you configure VDCs, install the Advanced Services license and enter the desired VDC. For more information, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 5.x.

Guidelines and Limitations

SNMP has the following configuration guidelines and limitations:

  • Cisco NX-OS supports read-only access to some SNMP MIBs. See the Cisco NX-OS MIB support list at the following URL for more information:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

Default Settings

Table 13-3 lists the default settings for SNMP parameters.

 

Table 13-3 Default SNMP Parameters

Parameters
Default

license notifications

Enabled.

Configuring SNMP

This section includes the following topics:

Note Be aware that the Cisco NX-OS commands for this feature may differ from those commands used in Cisco IOS.

Configuring SNMP Users

You can configure a user for SNMP.

BEFORE YOU BEGIN

Make sure that you are in the correct VDC. To change the VDC, use the switchto vdc command.

SUMMARY STEPS

1. config t

2. snmp-server user name [ auth { md5 | sha } passphrase [ auto ] [ priv [ aes-128 ] passphrase ] [ engineID id ] [ localizedkey] ]

3. show snmp user

4. copy running-config startup-config

DETAILED STEPS

 

 
Command
Purpose

Step 1

config t

 

Example:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)#

Places you in global configuration mode.

Step 2

snmp-server user name [ auth { md5 | sha } passphrase [auto ] [ p riv [ aes-128 ] passphrase] [engineID id ] [localizedkey ] ]

 

Example:

switch(config)# snmp-server user Admin auth sha abcd1234 priv abcdefgh

Configures an SNMP user with authentication and privacy parameters. The passphrase can be any case-sensitive alphanumeric string up to 64 characters. If you use the localizedkey keyword, the passphrase can be any case-sensitive alphanumeric string up to 130 characters.

The engineID format is a 12-digit colon-separated decimal number.

Step 3

show snmp user

 

Example:

switch(config-callhome)# show snmp user

(Optional) Displays information about one or more SNMP users.

Step 4

copy running-config startup-config

 

Example:

switch(config)# copy running-config startup-config

(Optional) Saves this configuration change.

This example shows how to configure the SNMP contact and location information:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)# snmp-server user Admin auth sha abcd1234 priv abcdefgh

 

Enforcing SNMP Message Encryption

You can configure SNMP to require authentication or encryption for incoming requests. By default, the SNMP agent accepts SNMPv3 messages without authentication and encryption. When you enforce privacy, Cisco NX-OS responds with an authorizationError for any SNMPv3 PDU request using securityLevel parameter of either noAuthNoPriv or authNoPriv.

Use the following command in global configuration mode to enforce SNMP message encryption for a user:

 

Command
Purpose

snmp-server user name enforcePriv

 

Example:

switch(config)# snmp-server user Admin enforcePriv

Enforces SNMP message encryption for this user.

Use the following command in global configuration mode to enforce SNMP message encryption for all users:

 

Command
Purpose

snmp-server globalEn forcePriv

 

Example:

switch(config)# snmp-server globalEnforcePriv

Enforces SNMP message encryption for all users.

Assigning SNMPv3 Users to Multiple Roles

After you configure an SNMP user, you can assign multiple roles for the user.

Note Only users belonging to a network-admin role can assign roles to other users.

Use the following command in global configuration mode to assign a role to an SNMP user:

 

Command
Purpose

snmp-server user name group

 

Example:

switch(config)# snmp-server user Admin superuser

Associates this SNMP user with the configured user role.

Creating SNMP Communities

You can create SNMP communities for SNMPv1 or SNMPv2c.

Use the following command in global configuration mode to create an SNMP community string:

 

Command
Purpose

snmp-server community name group { ro | rw }

 

Example:

switch(config)# snmp-server community public ro

Creates an SNMP community string.

Filtering SNMP Requests

You can assign an access list (ACL) to a community to filter incoming SNMP requests. If the assigned ACL allows the incoming request packet, SNMP processes the request. If the ACL denies the request, SNMP drops the request and sends a system message.

Create the ACL with the following parameters:

  • Source IP address
  • Destination IP address
  • Source port
  • Destination port
  • Protocol (UDP or TCP)

See the Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 5.x for more information on creating ACLs. The ACL applies to both IPv4 and IPv6 over UDP and TCP.

Use the following command in global configuration mode to assign an ACL to a community to filter SNMP requests:

 

Command
Purpose

snmp-server community community-name use-acl acl-name

 

Example:

switch(config)# snmp-server community public use-acl my_acl_for_public

Assigns an ACL to an SNMP community to filter SNMP requests.

Configuring SNMP Notification Receivers

You can configure Cisco NX-OS to generate SNMP notifications to multiple host receivers.

Use the following command in global configuration mode to configure a host receiver for SNMPv1 traps:

 

Command
Purpose

snmp-server host ip-address traps version 1 community [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 traps version 1 public

Configures a host receiver for SNMPv1 traps. The ip-address can be an IPv4 or IPv6 address. The community can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

Use the following command in global configuration mode to configure a host receiver for SNMPv2c traps or informs:

 

Command
Purpose

snmp-server host ip-address { traps | informs } version 2c community [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 informs version 2c public

Configures a host receiver for SNMPv2c traps or informs. The ip-address can be an IPv4 or IPv6 address. The community can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

Use the following command in global configuration mode to configure a host receiver for SNMPv3 traps or informs:

 

Command
Purpose

snmp-server host ip-address { traps | informs } version 3 { auth | noauth | priv } username [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 informs version 3 auth NMS

Configures a host receiver for SNMPv3 traps or informs. The ip-address can be an IPv4 or IPv6 address. The username can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

Note The SNMP manager must know the user credentials (authKey/PrivKey) based on the SNMP engine ID of the Cisco NX-OS device to authenticate and decrypt the SNMPv3 messages.

Configuring a Source Interface for SNMP Notifications

You can configure SNMP to use the IP address of an interface as the source IP address for notifications. When a notification is generated, its source IP address is based on the IP address of this configured interface.

You can configure this as follows:

  • All notifications sent to all SNMP notification receivers.
  • All notifications sent to a specific SNMP notification receiver. This configuration overrides the global source interface configuration.

Note Configuring the source interface IP address for outgoing trap packets does not guarantee that the device will use the same interface to send the trap. The source interface IP address defines the source address inside of the SNMP trap, and the connection is opened with the address of the egress interface as source.

Use the following command in global configuration mode to configure a host receiver on a source interface:

 

Command
Purpose

snmp-server host ip-address source-interface if-type if-number [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 source-interface ethernet 2/1

Configures a host receiver for SNMPv2c traps or informs. The ip-address can be an IPv4 or IPv6 address. Use ? to determine the supported interface types. The UDP port number range is from 0 to 65535.

This configuration overrides the global source interface configuration.

Use the following command in global configuration mode to configure a source interface for sending out all SNMP notifications:

 

Command
Purpose

snmp-server source-interface { traps | informs } if-type if-number

 

Example:

switch(config)# snmp-server source-interface traps ethernet 2/1

Configures a source interface for sending out SNMPv2c traps or informs. Use ? to determine the supported interface types.

Use the show snmp source-interface command to display information about configured source interfaces.

Configuring the Notification Target User

You must configure a notification target user on the device to send SNMPv3 inform notifications to a notification host receiver.

Cisco NX-OS uses the credentials of the notification target user to encrypt the SNMPv3 inform notification messages to the configured notification host receiver.

Note For authenticating and decrypting the received inform PDU, the notification host receiver should have the same user credentials as configured in Cisco NX-OS to authenticate and decrypt the informs.

Use the following command in global configuration mode to configure the notification target user:

 

Command
Purpose

snmp-server user name [ auth {md5 | sha} passphrase [auto ] [ p riv [ aes-128 ] passphrase] [engineID id ]

 

Example:

switch(config)# snmp-server user NMS auth sha abcd1234 priv abcdefgh engineID 00:00:00:63:00:01:00:10:20:15:10:03

Configures the notification target user with the specified engine ID for the notification host receiver. The engineID format is a 12-digit colon-separated decimal number.

Configuring SNMP Notification Receivers with VRFs

SNMP adds entries into the cExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MIB when you configure the VRF reachability and filtering options for an SNMP notification receiver.

Note You must configure the host before configuring the VRF reachability or filtering options.

You can configure Cisco NX-OS to use a configured VRF to reach the host receiver.

Use the following command in global configuration mode to configure a VRF to use for sending notifications to the host receiver:

 

Command
Purpose

snmp-server host ip-address use-vrf vrf_name [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 use-vrf Blue

Configures SNMP to use the selected VRF to communicate with the host receiver. The ip-address can be an IPv4 or IPv6 address. The VRF name can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535. This command adds an entry into thc ExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MB.

no snmp-server host ip-address use-vrf vrf_name [ udp_port number ]

 

Example:

switch(config)# no snmp-server host 192.0.2.1 use-vrf Blue

Removes the VRF reachability information for the configured host, and removes the entry from thc ExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MB.

The ip-address can be an IPv4 or IPv6 address.

Does not remove the host configuration.

You can configure Cisco NX-OS filter notifications based on the VRF in which the notification occurred.

Use the following command in global configuration mode to filter notifications based on a configured VRF:

 

Command
Purpose

snmp-server host ip-address filter-vrf vrf_name [ udp_port number ]

 

Example:

switch(config)# snmp-server host 192.0.2.1 filter-vrf Red

Filters notifications to the notification host receiver based on the configured VRF. The ip-address can be an IPv4 or IPv6 address. The VRF name can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

This command adds an entry into thc ExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MB.

no snmp-server host ip-address filter-vrf vrf_name

 

Example:

switch(config)# no snmp-server host 192.0.2.1 filter-vrf Red

Removes the VRF filter information for the configured host, and removes the entry from thc ExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MB.

The ip-address can be an IPv4 or IPv6 address. This command does not remove the host configuration.

Configuring SNMP to Send Traps Using an Inband Port

You can configure SNMP to send traps using an inband port. To do so, you must configure the source interface (at the global or host level) and the VRF used to send the traps.

SUMMARY STEPS

1. config t

2. snmp-server source-interface traps if-type if-number

3. show snmp source-interface

4. snmp-server host ip-address use-vrf vrf_name [ udp_port number ]

5. show snmp host

6. copy running-config startup-config

DETAILED STEPS

 

 
Command
Purpose

Step 1

config t

 

Example:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)#

Places you in global configuration mode.

Step 2

snmp-server source-interface traps if-type if-number

 

Example:

switch(config)# snmp-server source-interface traps ethernet 1/2

Globally configures a source interface for sending out SNMP traps. Use ? to determine the supported interface types.

You can configure the source interface at the global level or at a host level. When the source interface is configured globally, any new host configuration uses the global configuration to send the traps.

Note To configure a source interface at the host level, use this command: snmp-server host ip-address source-interface if-type if-number.

Step 3

show snmp source-interface

 

Example:

switch(config)# show snmp source-interface

(Optional) Displays information about configured source interfaces.

Step 4

snmp-server host ip-address use-vrf vrf_name [ udp_port number ]

 

Example:

switch(config)# snmp-server host 171.71.48.164 use_vrf default

Configures SNMP to use the selected VRF to communicate with the host receiver. The ip-address can be an IPv4 or IPv6 address. The VRF name can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535. This command adds an entry into the ExtSnmpTargetVrfTable of the CISCO-SNMP-TARGET-EXT-MB.

Note By default, SNMP sends the traps using the management VRF. If you do not want to use the management VRF, you must use this command to specify the desired VRF.

Step 5

show snmp host

 

Example:

switch(config)# show snmp host

(Optional) Displays information about configured SNMP hosts.

Step 6

copy running-config startup-config

 

Example:

switch(config)# copy running-config startup-config

(Optional) Saves this configuration change.

This example shows how to configure SNMP to send traps using a globally configured inband port:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)# snmp-server source-interface traps ethernet 1/2

switch(config)# show snmp source-interface

-------------------------------------------------------------------

Notification source-interface

-------------------------------------------------------------------

trap Ethernet1/2

 

inform -

-------------------------------------------------------------------

 

switch(config)# snmp-server host 171.71.48.164 use_vrf default

switch(config)# show snmp host

-------------------------------------------------------------------

Host Port Version Level Type SecName

-------------------------------------------------------------------

171.71.48.164 162 v2c noauth trap public

 

Use VRF: default

 

Source interface: Ethernet 1/2

-------------------------------------------------------------------

 

Enabling SNMP Notifications

You can enable or disable notifications. If you do not specify a notification name, Cisco NX-OS enables all notifications.

Table 13-4 lists the commands that enable the notifications for Cisco NX-OS MIBs.

Note The snmp-server enable traps command enables both traps and informs, depending on the configured notification host receivers.

 

Table 13-4 Enabling SNMP Notifications

MIB
Related Commands

All notifications

snmp-server enable traps

CISCO-AAA-SERVER-MIB

snmp-server enable traps aaa
snmp-server enable traps aaa server-state-change

CISCO-BGP4-MIB

snmp-server enable traps bgp

CISCO-STP-BRIDGE-MIB

snmp-server enable traps bridge
snmp-server enable traps bridge newroot
snmp-server enable traps bridge topologychange

CISCO-CALLHOME-MIB

snmp-server enable traps callhome
snmp-server enable traps callhome event-notify
snmp-server enable traps callhome smtp-send-fail

CISCO-CFS-MIB

snmp-server enable traps cfs
snmp-server enable traps cfs merge-failure
snmp-server enable traps cfs state-change-notif

CISCO-CONFIG-MAN-MIB

snmp-server enable traps config
snmp-server enable traps config ccmCLIRunningConfigChanged

CISCO-EIGRP-MIB

snmp-server enable traps eigrp [ tag ]

ENTITY-MIB, CISCO-ENTITY-SENSOR-
MIB

snmp-server enable traps entity
snmp-server enable traps entity entity_fan_status_change
snmp-server enable traps entity entity_mib_change
snmp-server enable traps entity entity_module_inserted
snmp-server enable traps entity entity_module_removed
snmp-server enable traps entity entity_module_status_change
snmp-server enable traps entity entity_power_out_change
snmp-server enable traps entity entity_power_status_change
snmp-server enable traps entity entity_unrecognised_module

CISCO-FEATURE-
CONTROL-MIB

snmp-server enable traps feature-control
snmp-server enable traps feature-control FeatureOpStatusChange

CISCO-HSRP-MIB

snmp-server enable traps hsrp
snmp-server enable traps hsrp state-change

CISCO-LICENSE-MGR-MIB

snmp-server enable traps license
snmp-server enable traps license notify-license-expiry
snmp-server enable traps license notify-license-expiry-warning
snmp-server enable traps license notify-licensefile-missing
snmp-server enable traps license notify-no-license-for-feature

IF-MIB

snmp-server enable traps link
snmp-server enable traps link IETF-extended-linkDown
snmp-server enable traps link IETF-extended-linkUp
snmp-server enable traps link cisco-extended-linkDown
snmp-server enable traps link cisco-extended-linkUp
snmp-server enable traps link linkDown
snmp-server enable traps link Up

OSPF-MIB, OSPF-TRAP-MIB

snmp-server enable traps ospf [ tag ]
 snmp-server enable traps ospf lsa
snmp-server enable traps ospf rate-limit rate

CISCO-PORT-SECURITY-
MIB

snmp-server enable traps port-security
snmp-server enable traps port-security access-secure-mac-violation
snmp-server enable traps port-security trunk-secure-mac-violation

CISCO-RF-MIB

snmp-server enable traps rf
snmp-server enable traps rf redundancy_framework

CISCO-RMON-MIB

snmp-server enable traps rmon
snmp-server enable traps rmon fallingAlarm
snmp-server enable traps rmon hcFallingAlarm
snmp-server enable traps rmon hcRisingAlarm
snmp-server enable traps rmon risingAlarm

SNMPv2-MIB

snmp-server enable traps snmp
snmp-server enable traps snmp authentication

CISCO-STPX-MIB

snmp-server enable traps stpx
snmp-server enable traps stpx inconsistency
snmp-server enable traps stpx loop-inconsistency
snmp-server enable traps stpx root-inconsistency

CISCO-SYSTEM-EXT-MIB

sysmgr
sysmgr cseFailSwCoreNotifyExtended

UPGRADE-MIB

upgrade
upgrade UpgradeJobStatusNotify
upgrade UpgradeOpNotifyOnCompletion

ZONE-MIB

zone
zone default-zone-behavior-change
zone merge-failure
zone merge-success
zone request-reject1
zone unsupp-mem

Use the following commands in global configuration mode to enable the specified notification:

 

Command
Purpose

snmp-server enable traps

 

Example:

switch(config)# snmp-server enable traps

Enables all SNMP notifications.

snmp-server enable traps aaa [ server-state-change ]

 

Example:

switch(config)# snmp-server enable traps aaa

Enables AAA SNMP notifications. Optionally, enables the following specific notifications:

  • server-state-change —Enables AAA server state-change notifications.

snmp-server enable traps bgp

 

Example:

switch(config)# snmp-server enable traps bgp

Enables BGP SNMP notifications.

snmp-server enable traps bridge
 [ newroot ]
[ topologychange ]

 

Example:

switch(config)# snmp-server enable traps bridge

Enables STP bridge SNMP notifications. Optionally, enables the following specific notifications:

  • newroot —Enables STP new root bridge notifications.
  • topologychange —Enables STP bridge topology-change notifications.

snmp-server enable traps callhome [ event-notify]
[smtp-send-fail ]

 

Example:

switch(config)# snmp-server enable traps callhome

Enables Call Home notifications. Optionally, enables the following specific notifications:

  • event-notify —Enables Call Home external event notifications.
  • smtp-send-fail —Enables Simple Mail Transfer Protocol (SMTP) message send fail notifications.

snmp-server enable traps cfs
 [ merge-failure]
[state-change-notif ]

 

Example:

switch(config)# snmp-server enable traps cfs

Enables Cisco Fabric Services (CFS) notifications. Optionally, enables the following specific notifications:

  • merge-failure —Enables CFS merge-failure notifications.
  • state-change-notif —Enables CFS state-change notifications.

snmp-server enable traps config [ ccmCLIRunningConfigChanged ]

 

Example:

switch(config)# snmp-server enable traps config

Enables SNMP notifications for configuration changes.

  • ccmCLIRunningConfigChanged —Enables SNMP notifications for configuration changes in the running or startup configuration.

snmp-server enable traps eigrp [ tag ]

 

Example:

switch(config)# snmp-server enable traps eigrp

Enables CISCO-EIGRP-MIB SNMP notifications.

snmp-server enable traps entity [ entity_fan_status_change]
[entity_mib_change ]

[ entity_module_inserted ]

[ entity_module_removed ]

[ entity_module_status_change ]

[ entity_power_out_change ]

[ entity_power_status_change ]

[ entity_unrecognised_module ]

 

Example:

switch(config)# snmp-server enable traps entity

Enables ENTITY-MIB SNMP notifications. Optionally, enables the following specific notifications:

  • entity_fan_status_change —Enables entity fan status-change notifications.
  • entity_mib_change —Enables entity MIB change notifications.
  • entity_module_inserted —Enables entity module inserted notifications.
  • entity_module_removed —Enables entity module removed notifications.
  • entity_module_status_change —Enables entity module status-change notifications.
  • entity_power_out_change —Enables entity power-out change notifications.
  • entity_power_status_change —Enables entity power status-change notifications.
  • entity_unrecognised_module —Enables entity unrecognized module notifications.

snmp-server enable traps feature-control [ FeatureOpStatusChange ]

 

Example:

switch(config)# snmp-server enable traps feature-control

Enables feature-control SNMP notifications. Optionally, enables the following specific notifications:

  • FeatureOpStatusChange —Enables feature operation status-change notifications.

snmp-server enable traps hsrp [ state-change ]

 

Example:

switch(config)# snmp-server enable traps hsrp

Enables CISCO-HSRP-MIB SNMP notifications. Optionally, enables the following specific notifications:

  • state-change —Enables HSRP state-change notifications.

snmp-server enable traps license [ notify-license-expiry ] [ notify-license-expiry-warning ] [ notify-licensefile-missing ] [ notify-no-license-for-feature ]

 

Example:

switch(config)# snmp-server enable traps license

Enables license SNMP notifications. Optionally, enables the following specific notifications:

  • notify-license-expiry —Enables license expiry notifications.
  • notify-license-expiry-warning —Enables license expiry warning notifications.
  • notify-licensefile-missing —Enables license file-missing notifications.
  • notify-no-license-for-feature —Enables no-license-installed-for-feature notifications.

snmp-server enable traps link

[ IETF-extended-linkDown ] [ IETF-extended-linkUp ] [ cisco-extended-linkDown ] [ cisco-extended-linkUp ]
[ linkDown ]
[ linkUp ]

 

Example:

switch(config)# snmp-server enable traps link

Enables IF-MIB link notifications. Optionally, enables the following specific notifications:

  • IETF-extended-linkDown —Enables Internet Engineering Task Force (IETF) extended link state down notifications.
  • IETF-extended-linkUp —Enables Internet Engineering Task Force (IETF) extended link state up notifications.
  • cisco-extended-linkDown —Enables Cisco extended link state down notifications.
  • cisco-extended-linkUp —Enables Cisco extended link state up notifications.
  • linkDown —Enables IETF link state down notifications.
  • linkUp —Enables IETF link state up notifications.

snmp-server enable traps ospf [ tag ]

[ lsa ]
[ rate-limit rate ]

 

Example:

switch(config)# snmp-server enable traps ospf

Enables open shortest path first (OSPF) notifications. Optionally, enables the following specific notifications:

  • lsa —Enables OSPF LSA notifications.
  • rate-limit rate —Enables rate limits on OSPF notifications. The range is from 2 to 60 seconds. The default is 10 seconds.

snmp-server enable traps port-security

[ access-secure-mac-violation ] [ trunk-secure-mac-violation ]

 

Example:

switch(config)# snmp-server enable traps port-security

Enables port-security SNMP notifications. Optionally, enables the following specific notifications:

  • access-secure-mac-violation —Enables secure machine access control (MAC) violation notifications.
  • trunk-secure-mac-violation —Enables virtual LAN (VLAN) secure MAC violation notifications.

snmp-server enable traps rf [ redundancy-framework ]

 

Example:

switch(config)# snmp-server enable traps rf

Enables redundancy framework (RF) SNMP notifications. Optionally, enables the following specific notifications:

  • redundancy-framework —Enables RF Supervisor switchover MIB notifications.

snmp-server enable traps rmon
 [ fallingAlarm ]
[ hcFallingAlarm ]
[ hcRisingAlarm ]
[ risingAlarm ]

 

Example:

switch(config)# snmp-server enable traps rmon

Enables remote monitoring (RMON) SNMP notifications. Optionally, enables the following specific notifications:

  • fallingAlarm —Enables RMON falling alarm notifications.
  • hcFallingAlarm —Enables RMON high-capacity falling alarm notifications.
  • hcRisingAlarm —Enables RMON high-capacity rising alarm notifications.
  • risingAlarm —Enables RMON rising alarm notifications.

snmp-server enable traps snmp [ authentication ]

 

Example:

switch(config)# snmp-server enable traps snmp

Enables general SNMP notifications. Optionally, enables the following specific notifications:

  • authentication —Enables SNMP authentication notifications.

snmp-server enable traps stpx [ inconsistency ]
[ loop-inconsistency ]
[root-inconsistency ]

 

Example:

switch(config)# snmp-server enable traps stpx

Enables STPX MIB notifications. Optionally, enables the following specific notifications:

  • inconsistency —Enables SNMP STPX MIB inconsistency update notifications.
  • loop-inconsistency —Enables SNMP STPX MIB loop-inconsistency update notifications.
  • root-inconsistency —Enables SNMP STPX MIB root-inconsistency update notifications.

snmp-server enable traps sysmgr [ cseFailSwCoreNotifyExtended ]

Example:

switch(config)# snmp-server enable traps sysmgr

Enables software change notifications. Optionally, enables the following specific notifications:

  • cseFailSwCoreNotifyExtended —Enables software core notifications.

snmp-server enable traps upgrade [ UpgradeJobStatusNotify ]
[ UpgradeOpNotifyOnCompletion ]

Example:

switch(config)# snmp-server enable traps upgrade

Enables upgrade notifications. Optionally, enables the following specific notifications:

  • UpgradeJobStatusNotify —Enables upgrade job status notifications.
  • UpgradeOpNotifyOnCompletion —Enables upgrade global status notifications.

snmp-server enable traps vtp
 [ notifs ]
[ vlancreate ]

[ vlandelete ]

Example:

switch(config)# snmp-server enable traps vtp

Enables upgrade notifications. Optionally, enables the following specific notifications:

  • notifs —Enables VTP notifications.
  • vlancreate —Enables VLAN creation notifications.
  • vlandelete —Enables VLAN deletion notifications.

snmp-server enable traps zone [ default-zone-behavior-change ]
[ merge-failure ]
[ merge-success ]
[ request-reject1 ]
[ unsupp-mem ]

Example:

switch(config)# snmp-server enable traps zone

Enables default zone change notifications. Optionally, enables the following specific notifications:

  • default-zone-behavior-change —Enables default zone behavior change notifications.
  • merge-failure —Enables merge failure notifications.
  • merge-success —Enables merge success notifications.
  • request-reject1 —Enables request reject notifications.
  • unsupp-mem —Enables unsupported member notifications.

Disabling LinkUp/LinkDown Notifications on an Interface

You can disable linkUp and linkDown notifications on an individual interface. You can use these limit notifications on a flapping interface (an interface that transitions between up and down repeatedly).

Use the following command in interface configuration mode to disable linkUp/linkDown notifications for the interface:

 

Command
Purpose

no snmp trap link-status

 

Example:

switch(config-if)# no snmp trap link-status

Disables SNMP link-state traps for the interface. This command is enabled by default.

Displaying SNMP ifIndex for an Interface

The SNMP ifIndex is used across multiple SNMP MIBs to link related interface information. The ifIndex is also used by NetFlow to collect information on an interface.

Use the following command in any mode to display the SNMP ifIndex values for interfaces:

 

Command
Purpose

show interface snmp-ifindex

 

Example:

switch# show interface snmp-ifindex | grep -i Eth12/1

Eth12/1 441974784 (0x1a580000)

Displays the persistent SNMP ifIndex value from IF-MIB for all interfaces. Optionally, use the | keyword and the grep keyword to search for a particular interface in the output.

Enabling a One-time Authentication for SNMP over TCP

You can enable a one-time authentication for SNMP over a TCP session.

Use the following command in global configuration mode to enable a one-time authentication for SNMP over TCP:

 

Command
Purpose

snmp-server tcp-session [ auth ]

 

Example:

switch(config)# snmp-server tcp-session

Enables a one-time authentication for SNMP over a TCP session. The default is disabled.

Assigning the SNMP Device Contact and Location Information

You can assign the device contact information, which is limited to 32 characters (without spaces) and the device location.

BEFORE YOU BEGIN

Make sure that you are in the correct VDC. To change the VDC, use the switchto vdc command.

SUMMARY STEPS

1. config t

2. snmp-server contact name

3. snmp-server location name

4. show snmp

5. copy running-config startup-config

DETAILED STEPS

 

 
Command
Purpose

Step 1

config t

 

Example:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)#

Places you in global configuration mode.

Step 2

snmp-server contact name

 

Example:

switch(config)# snmp-server contact Admin

Configures sysContact, which is the SNMP contact name.

Step 3

snmp-server location name

 

Example:

switch(config)# snmp-server location Lab-7

Configures sysLocation, which is the SNMP location.

Step 4

show snmp

 

Example:

switch(config)# show snmp

(Optional) Displays information about one or more destination profiles.

Step 5

copy running-config startup-config

 

Example:

switch(config)# copy running-config startup-config

(Optional) Saves this configuration change.

This example shows how to configure the SNMP contact and location information:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)# snmp contact Admin

switch(config)# snmp location Lab-7

 

Configuring the Context to Network Entity Mapping

You can configure an SNMP context to map to a logical network entity, such as a protocol instance or VRF.

BEFORE YOU BEGIN

Make sure that you are in the correct VDC. To change the VDC, use the switchto vdc command.

Determine the logical network entity instance. For more information on VRFs and protocol instances, see the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 5.x , or the Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide, Release 5.x .

SUMMARY STEPS

1. config t

2. snmp-server context context-name [ instance instance-name ] [ vrf vrf-name ] [ topology topology-name ]

3. snmp-server mib community-map community-name context context-name

4. show snmp context

5. copy running-config startup-config

DETAILED STEPS

 

 
Command
Purpose

Step 1

config t

 

Example:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)#

Places you in global configuration mode.

Step 2

snmp-server context context-name [ instance instance-name ] [ vrf vrf-name ] [ topology topology-name ]

 

Example:

switch(config)# snmp-server context public1 vrf red

Maps an SNMP context to a protocol instance, VRF, or topology. The names can be any alphanumeric string up to 32 characters.

Step 3

snmp-server mib community-map community-name context context-name

 

Example:

switch(config)# snmp-server mib community-map public context public1

(Optional) Maps an SNMPv2c community to an SNMP context. The names can be any alphanumeric string up to 32 characters.

Step 4

show snmp context

 

Example:

switch(config)# show snmp context

(Optional) Displays information about one or more SNMP contexts.

Step 5

copy running-config startup-config

 

Example:

switch(config)# copy running-config startup-config

(Optional) Saves this configuration change.

This example shows how to map VRF red to the SNMPv2c public community string:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)# vrf context red

switch(config-vrf)# exit

switch(config)# snmp-server context public1 vrf red

switch(config)# snmp-server mib community-map public context public1

 

This example shows how to map OSPF instance Enterprise to the same SNMPv2c public community string:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.

switch(config)# feature ospf

switch(config)# router ospf Enterprise

switch(config-router)# exit

switch(config)# snmp-server context public1 instance Enterprise

switch(config)# snmp-server mib community-map public context public1

 

Use the following command in global configuration mode to delete the mapping between an SNMP context and a logical network entity:

 

Command
Purpose

no snmp-server context context-name [ instance instance-name ] [ vrf vrf-name ] [ topology topology-name ]

 

Example:

switch(config)# no snmp-server context public1

Deletes the mapping between an SNMP context and a protocol instance, VRF, or topology. The names can be any alphanumeric string up to 32 characters.

Note Do not enter an instance, VRF, or topology to delete a context mapping. If you use the instance, vrf, or topology keywords, you configure a mapping between the context and a zero-length string.

Disabling SNMP

You can disable SNMP on a device.

Use the following command in global configuration mode to disable SNMP:

 

Command
Purpose

no snmp-server protocol enable

 

Example:

switch(config)# no snmp-server protocol enable

Disables SNMP. This command is enabled by default.

Modifying the AAA Synchronization Time

You can modify how long Cisco NX-OS holds the synchronized user configuration.

Use the following command in global configuration mode to modify the AAA synchronization time:

 

Command
Purpose

snmp-server aaa-user cache-timeout seconds

 

Example:

switch(config)# snmp-server aaa-user cache-timeout 1200.

Configures how long the AAA synchronized user configuration stays in the local cache. The range is from 1 to 86400 seconds. The default is 3600.

Verifying the SNMP Configuration

To display the SNMP configuration information, perform one of the following tasks:

 

Command
Purpose

show interface snmp-ifindex

Displays the SNMP ifIndex value for all interfaces (from IF-MIB).

show running-config snmp [ all ]

Displays the SNMP running configuration.

show snmp

Displays the SNMP status.

show snmp community

Displays the SNMP community strings.

show snmp context

Displays the SNMP context mapping.

show snmp engineID

Displays the SNMP engineID.

show snmp group

Displays SNMP roles.

show snmp host

Displays information about configured SNMP hosts.

show snmp session

Displays SNMP sessions.

show snmp source-interface

Displays information about configured source interfaces.

show snmp trap

Displays the SNMP notifications enabled or disabled.

show snmp user

Displays SNMPv3 users.

Configuration Examples for SNMP

This example shows how to configure Cisco NX-OS to send the Cisco linkUp or Down notifications to one notification host receiver using the Blue VRF and defines two SNMP users, Admin and NMS:

config t
snmp-server contact Admin@company.com
snmp-server user Admin auth sha abcd1234 priv abcdefgh
snmp-server user NMS auth sha abcd1234 priv abcdefgh engineID 00:00:00:63:00:01:00:22:32:15:10:03
snmp-server host 192.0.2.1 informs version 3 auth NMS
snmp-server host 192.0.2.1 use-vrf Blue
snmp-server enable traps link cisco
 
 

This example shows how to configure SNMP to send traps using an inband port configured at the host level:

switch# config t

Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# snmp-server host 171.71.48.164 version 2c public
switch(config)# snmp-server host 171.71.48.164 source-interface ethernet 1/2
switch(config)# show snmp host
-------------------------------------------------------------------
Host Port Version Level Type SecName
-------------------------------------------------------------------
171.71.48.164 162 v2c noauth trap public
 

Source interface: Ethernet 1/2

-------------------------------------------------------------------

 
switch(config)# snmp-server host 171.71.48.164 use_vrf default
switch(config)# show snmp host
-------------------------------------------------------------------
Host Port Version Level Type SecName
-------------------------------------------------------------------
171.71.48.164 162 v2c noauth trap public
 
Use VRF: default
 
Source interface: Ethernet 1/2
-------------------------------------------------------------------
 

Additional References

For additional information related to implementing SNMP, see the following sections:

Related Documents

Related Topic
Document Title

SNMP CLI commands

Cisco Nexus 7000 Series NX-OS System Management Command Reference

VDCs and VRFs

Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 5.x

MIBs

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

—

MIBs

MIBs
MIBs Link
  • SNMP-COMMUNITY-MIB
  • SNMP-FRAMEWORK-MIB
  • SNMP-NOTIFICATION-MIB
  • SNMP-TARGET-MIB
  • SNMPv2-MIB

To locate and download MIBs, go to the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

Feature History for SNMP

Table 13-5 lists the release history for this feature.

 

Table 13-5 Feature History for SNMP
Feature Name
Releases
Feature Information

SNMP protocol

5.2(1)

No change from Release 5.1.

SNMP protocol

5.1(1)

No change from Release 5.0.

SNMP notifications

5.0(2)

Updated the snmp-server enable traps commands. See the “Enabling SNMP Notifications” section .

IPv6 support

4.2(1)

Supports configuring IPv6 SNMP hosts.

Filter SNMP requests by community using an ACL

4.2(1)

Assigns an ACL to an SNMP community to filter SNMP requests. See the “Filtering SNMP Requests” section.

Use interfaces for SNMP notification receivers

4.2(1)

Adds support to designate an interface to act as the source interface for SNMP notifications. See the “Configuring SNMP Notification Receivers” section.

SNMP AAA synchronization

4.0(3)

Adds ability to modify the synchronized user configuration timeout. See the “Modifying the AAA Synchronization Time” section.

SNMP protocol

4.0(3)

Added ability to disable the SNMP protocol. See the “Disabling SNMP” section.