Cisco Nexus 1000V System Management Configuration Guide, Release 4.2(1)SV2(2.1)
Configuring SNMP
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Configuring SNMP

Contents

Configuring SNMP

This chapter contains 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.

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.


Note


SNMP Role Based Access Control (RBAC) is not supported.


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

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. 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. The 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 the Cisco NX-OS never receives a response, it can send the inform request again.

You can configure Cisco Nexus NX-OS to send notifications to multiple host receivers.

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 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.

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.

The following table identifies what the combinations of security models and levels mean.

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

Provides authentication based on the HMAC-MD5 or HMAC-SHA algorithms. Provides Data Encryption Standard (DES) 56-bit encryption in addition to authentication based on the Cipher Block Chaining (CBC) DES (DES-56) standard.

User-Based Security Model

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

The 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 along with the aes-128 token indicates 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 Nexus 1000V 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 as the authentication and privacy passphrases for the SNMP user.
  • If you delete a user using either SNMP or the CLI, the user is 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 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 Modifying the AAA Synchronization Time 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 roles as groups 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.

High Availability

Stateless restarts for SNMP are supported. After a reboot or supervisor switchover, the running configuration is applied.

Guidelines and Limitations for SNMP

  • Read-only access to some SNMP MIBs is supported. 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
  • SNMP Role Based Access Control (RBAC) is not supported.
  • The SNMP set command is supported by the following Cisco MIBs:
    • CISCO-IMAGE-UPGRADE-MIB
    • CISCO-CONFIG-COPY-MIB
  • The recommended SNMP polling interval time is 5 minutes.

Default Settings for SNMP

Parameters

Default

license notifications

enabled

Configuring SNMP

This section includes the following topics:

  • Configuring SNMP
  • Users Enforcing SNMP Message Encryption
  • Creating SNMP Communities
  • Configuring SNMP Notification Receivers
  • Configuring the Notification Target User
  • Enabling SNMP Notifications
  • Disabling LinkUp/LinkDown Notifications on an Interface
  • Enabling a One-time Authentication for SNMP over TCP
  • Assigning the SNMP Switch Contact and Location Information
  • Disabling SNMP
  • Modifying the AAA Synchronization Time

Configuring SNMP Users

Before You Begin

Before beginning this procedure, you must be logged in to the CLI in EXEC mode.

Procedure
     Command or ActionPurpose
    Step 1switch# configure terminal 

    Places you in global configuration mode.

     
    Step 2switch(config)# snmp-server user name [auth {md5 | sha} passphrase [auto] [priv [aes-128] passphrase] [engineID id] [localizedkey]] 

    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 localizekey keyword, the passphrase can be any case-sensitive, alphanumeric string up to 130 characters.

    The name argument is the name of a user who can access the SNMP engine.

    The auth keyword enables one-time authentication for SNMP over a TCP session. It is optional.

    The md5 keyword specifies HMAC MD5 algorithm for authentication. It is optional.

    The sha keyword specifies HMAC SHA algorithm for authentication. It is optional.

    The priv keyword specifies encryption parameters for the user. It is optional.

    The aes-128 keyword specifies a 128-byte AES algorithm for privacy. It is optional.

    The engineID keyword specifies the engineID for configuring the notification target user (for V3 informs). It is optional.

    The id is a 12-digit colon-separated decimal number.

     
    Step 3switch(config-callhome)# show snmp user  (Optional)

    Displays information about one or more SNMP users.

     
    Step 4switch(config-callhome)# copy running-config startup-config  (Optional)

    Saves the running configuration persistently through reboots and restarts by copying it to the startup configuration.

     
    switch(config)# configure terminal
    switch(config)# snmp-server user Admin auth sha Axlm1234# priv Axlm1234#
    switch(config)# show snmp user
    ______________________________________________________________
    SNMP USERS
    ______________________________________________________________
    User Auth Priv(enforce) Groups
    ____ ____ _____________ ______
    Admin sha des(no) network-operator
    admin md5 des(no) network-admin
    ______________________________________________________________
    NOTIFICATION TARGET USERS (configured for sending V3 Inform)
    ______________________________________________________________
    User Auth Priv
    ____ ____ ____
    switch(config)#
    

    Enforcing SNMP Message Encryption for All Users

    Procedure
       Command or ActionPurpose
      Step 1switch(config)# snmp-server globalEnforcePriv  

      Enforces SNMP message encryption for all users.

       
      switch(config)# snmp-server galobalEnforcePriv 
      switch(config)# show snmp user 
      ______________________________________________________________
      SNMP USERS [global privacy flag enabled]
      ______________________________________________________________
      
      User                          Auth  Priv(enforce) Groups                        
      ____                          ____  _____________ ______                        
      Admin                         sha   des(no)       network-operator              
      
      admin                         md5   des(no)       network-admin                 
      
      ______________________________________________________________
       NOTIFICATION TARGET USERS (configured  for sending V3 Inform) 
      ______________________________________________________________
      
      User                          Auth  Priv 
      ____                          ____  ____ 
      switch(config)# 

      Creating SNMP Communities

      You can create SNMP communities for SNMPv1 or SNMPv2c.

      Before You Begin

      You must be in global configuration mode.

      Procedure
         Command or ActionPurpose
        Step 1 switch(config)# snmp-server community name {ro | rw} 

        Creates an SNMP community string.

         
        switch(config)# snmp-server community public ro 
        switch(config)# show snmp community
        Community Group / Access context acl_filter
        ----------------------------- -------------- ------- ----------
        public network-operator
        switch(config)#

        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. The ACL applies to IPv4 over UDP and TCP. After creating the ACL, assign the ACL to the SNMP community. For more information on creating ACLs, see the Cisco Nexus 1000V for VMware Security Configuration Guide.

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

        Before You Begin

        Create an ACL to assign to the SNMP community. Assign the ACL to the SNMP community. Create the ACL with the following parameters:

        • Source IP address
        • Destination IP address
        • Source Port
        • Destination Port
        • Protocol (UDP or TCP)
        Procedure
           Command or ActionPurpose
          Step 1 switch# configure terminal 

          Enters the global configurationmode.

           
          Step 2switch(config-callhome)# snmp-server community community-name use-acl acl-name  

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

           
          Step 3switch(config-callhome)# ip access-list acl_for_community 

          Configures IP ACL.

           
          Step 4switch(config-callhome)# statistics per-entry 

          Configures statistics.

           
          Step 5switch(config-callhome)# permit udp any any 

          Permits UDP protocol.

           
          Step 6switch(config-callhome)# show ip access-lists  (Optional)

          Displays show command output.

           
          Step 7switch(config-callhome)# snmp-server community public use-acl acl_for_community 

          Configures SNMP community.

           
          Step 8switch(config-callhome)# showsnmp community  (Optional)

          Displays show command output.

           

          This example shows how to filter SNMP requests:

          switch(config)# show ip access-lists
          IPV4 ACL acl_for_community
          statistics per-entry
          10 permit udp any any
          switch(config)# show snmp community
          Community Group / Access context acl_filter
          ----------------------------- -------------- ------- ----------
          public network-operator acl_for_community

          Configuring SNMP Notification Receivers

          Configuring a Host Receiver for SNMPv1 Traps

          Before You Begin

          You must be in global configuration mode.

          Procedure
             Command or ActionPurpose
            Step 1switch(config)# snmp-server host ip-address traps version 1 community [udp_port number] 

            Configures a host receiver for SNMPv1 traps. The community can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

             
            switch(config)# snmp-server host 192.0.2.1 traps version 1 public
            switch(config)# show snmp host 
            -------------------------------------------------------------------
            Host                            Port Version  Level  Type   SecName                         
            -------------------------------------------------------------------
            192.0.2.1                       162  v1       noauth trap   public                          
            -------------------------------------------------------------------
            switch(config)# 

            Configuring a Host Receiver for SNMPv2c Traps or Informs

            Before You Begin

            You must be in global configuration mode.

            Procedure
               Command or ActionPurpose
              Step 1switch(config)# snmp-server host ip-address {traps | informs} version 2c community [udp_port number]  

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

               
              switch(config)# snmp-server host 192.0.2.1 informs version 2c public
              switch(config)# show snmp host 
              -------------------------------------------------------------------
              Host                            Port Version  Level  Type   SecName                         
              -------------------------------------------------------------------
              192.0.2.1                       162  v2c      noauth inform public                          
              -------------------------------------------------------------------
              switch(config)# 
              
              

              Configuring a Host Receiver for SNMPv3 Traps or Informs


              Note


              The SNMP manager must know the user credentials (authKey/PrivKey) based on the SNMP engine ID of the Cisco Nexus 1000V device to authenticate and decrypt the SNMPv3 messages


              Before You Begin

              You must be in global configuration mode.

              Procedure
                 Command or ActionPurpose
                Step 1switch(config)# snmp-server host ip-address {traps | informs} version 3 {auth | noauth | priv} username [udp_port number] 

                Configures a host receiver for SNMPv2c traps or informs. The username can be any alphanumeric string up to 255 characters. The UDP port number range is from 0 to 65535.

                 
                switch# configure terminal
                switch(config)# snmp-server host 192.0.2.1 informs version 3 auth Admin
                switch(config)# show snmp host 
                -------------------------------------------------------------------
                Host Port Version Level Type SecName 
                -------------------------------------------------------------------
                192.0.2.1 162 v3 auth inform Admin 
                -------------------------------------------------------------------
                switch(config)#   
                
                

                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

                The 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 inform s


                Procedure
                   Command or ActionPurpose
                  Step 1switch(config)# snmp-server user name [auth {md5 | sha} passphrase [auto] [priv [aes-128] passphrase] [engineID id] 

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

                   
                  switch(config)# snmp-server user Admin auth sha Axlm1234# priv Axlm1234#
                  engineID 00:00:00:63:00:01:00:10:20:15:10:03
                  switch(config)# show snmp user
                  ______________________________________________________________
                  SNMP USERS [global privacy flag enabled]
                  ______________________________________________________________
                  User Auth Priv(enforce) Groups
                  ____ ____ _____________ ______
                  admin md5 des(no) network-admin
                  ______________________________________________________________
                  NOTIFICATION TARGET USERS (configured for sending V3 Inform)
                  ______________________________________________________________
                  User Auth Priv
                  ____ ____ ____
                  Admin sha des
                  (EngineID 0:0:0:63:0:1:0:10:20:15:10:3)
                  switch(config)#

                  Enabling SNMP Notifications

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

                  The following table 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.


                  MIB

                  Related Commands

                  All notifications

                  snmp-server enable traps

                  CISCO-AAA-SERVER-MIB

                  snmp-server enable traps aaa

                  ENITY-MIB

                  snmp-server enable traps entity

                  CISCO-ENTITY-FRU-CONTROL-MIB

                  snmp-server enable traps entity fru

                  CISCO-LICENSE-MGR-MIB

                  snmp-server enable traps license

                  IF-MIB

                  snmp-server enable traps link

                  SNMPv2-MIB

                  snmp-server enable traps snmp

                  snmp-server enable traps snmp authentication

                  The license notifications are enabled by default. All other notifications are disabled by default.

                  Before You Begin

                  You must be in global configuration mode.

                  Procedure
                     Command or ActionPurpose
                    Step 1switch(config)# snmp-server enable traps 

                    Enables all SNMP notifications.

                     
                    Step 2switch(config)# snmp-server enable traps aaa [server-state-change] 

                    Enables the AAA SNMP notifications.

                     
                    Step 3switch(config)# snmp-server enable traps entity [fru] 

                    Enables the ENTITY-MIB SNMP notifications.

                     
                    Step 4switch(config)# snmp-server enable traps license 

                    Enables the license SNMP notification.

                     
                    Step 5switch(config)# snmp-server enable traps link  

                    Enables the link SNMP notifications.

                     
                    Step 6switch(config)# snmp-server enable traps snmp [authentication]  

                    Enables the SNMP agent notifications.

                     

                    This example displays how to enable SNMP notifications:

                    switch(config)# snmp-server enable traps
                    switch(config)# snmp-server enable traps aaa
                    switch(config)# snmp-server enable traps entity
                    switch(config)# snmp-server enable traps license
                    switch(config)# snmp-server enable traps link
                    switch(config)# snmp-server enable traps snmp

                    Disabling LinkUp/LinkDown Notifications on an Interface

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

                    Before You Begin

                    You must be in interface configuration mode.

                    Procedure
                       Command or ActionPurpose
                      Step 1switch(config-if)# no snmp trap link-status  

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

                       
                      switch# show running-config interface vethernet 1
                      interface Vethernet1
                      inherit port-profile
                      dynpp_d50369db-2fed-405d-ad84-a6bf89718d2c_f006e797-da04-4f29-9a0f-901294bc8b8f
                      description TEST, Network Adapter
                      dvport uuid "70D66D72-CDD9-4B68-9596-27E8F8E06F6D--0"
                      switch# conf
                      Enter configuration commands, one per line. End with CNTL/Z.
                      switch(config)# interface vethernet 1
                      switch(config-if)# no snmp trap link-status
                      switch(config-if)# show running-config interface vethernet 1
                      interface Vethernet1
                      inherit port-profile
                      dynpp_d50369db-2fed-405d-ad84-a6bf89718d2c_f006e797-da04-4f29-9a0f-901294bc8b8f
                      description TEST, Network Adapter
                      dvport uuid "70D66D72-CDD9-4B68-9596-27E8F8E06F6D--0"
                      no snmp trap link-status
                      

                      Enabling a One-time Authentication for SNMP over TCP

                      Before You Begin

                      You must be in global configuration mode.

                      Procedure
                         Command or ActionPurpose
                        Step 1switch(config)# snmp-server tcp-session [auth] 

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

                         
                        switch# configure terminal
                        Enter configuration commands, one per line. End with CNTL/Z.
                        switch(config)# snmp-server tcp-session
                        switch(config)# show snmp | grep "Tcp"
                        SNMP Tcp Authentication Flag : Enabled.
                        switch(config)#

                        Assigning the SNMP Switch Contact and Location Information

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

                        Before You Begin

                        Log in to the CLI in EXEC mode.

                        Procedure
                           Command or ActionPurpose
                          Step 1switch# configure terminal 

                          Enters global configuration mode.

                           
                          Step 2switch(config)# snmp-server contact name 

                          Configures sysContact, which is the SNMP contact name.

                           
                          Step 3switch(config)# snmp-server location name 

                          Configures sysLocation, which is the SNMP location.

                           
                          Step 4switch(config)# show snmp  (Optional)

                          Displays information about one or more destination profiles.

                           
                          Step 5switch(config)# copy running-config startup-config  (Optional)

                          Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

                           
                          switch# configure terminal
                          Enter configuration commands, one per line. End with CNTL/Z.
                          switch(config)# snmp-server contact Admin
                          switch(config)# snmp-server location Lab
                          switch(config)# show snmp | grep sys
                          sys contact: Admin
                          sys location: Lab
                          switch(config)# copy running-config startup-config
                          

                          Disabling SNMP

                          Before You Begin

                          You must be in global configuration mode.

                          Procedure
                             Command or ActionPurpose
                            Step 1 switch(config)# no snmp-server protocol enable 

                            Disables the SNMP protocol. This command is enabled by default.

                             
                            switch(config)# no snmp-server protocol enable
                            switch(config)# show snmp | grep protocol
                            SNMP protocol : Disabled
                            switch(config)#
                            

                            Modifying the AAA Synchronization Time

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

                            Before You Begin

                            You must be in global configuration mode.

                            Procedure
                               Command or ActionPurpose
                              Step 1 switch(config)# snmp-server aaa-user cache-timeout seconds 

                              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.

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

                              Verifying the SNMP Configuration

                              Use one of the following commands to verify the configuration:

                              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 session

                              Displays SNMP sessions.

                              show snmp trap

                              Displays the SNMP notifications enabled or disabled.

                              show snmp user

                              Displays SNMPv3 users.

                              show snmp host

                              Displays information about configured SNMP hosts.

                              Configuration Example for SNMP

                              This example shows how to configure Cisco NX-OS to send linkUp/Down notifications to one notification host receiver.

                              switch(config)# snmp-server user Admin auth sha Axlm1234# priv Axlm1234#
                              switch(config)# snmp-server host 192.0.2.1 traps version 3 priv Admin
                              switch(config)# snmp-server enable traps link
                              switch(config)# show snmp user
                              ______________________________________________________________
                              SNMP USERS [global privacy flag enabled]
                              ______________________________________________________________
                              User Auth Priv(enforce) Groups
                              ____ ____ _____________ ______
                              Admin sha des(no) network-operator
                              admin md5 des(no) network-admin
                              ______________________________________________________________
                              NOTIFICATION TARGET USERS (configured for sending V3 Inform)
                              ______________________________________________________________
                              User Auth Priv
                              ____ ____ ____
                              switch(config)# show snmp host
                              -------------------------------------------------------------------
                              Host Port Version Level Type SecName
                              -------------------------------------------------------------------
                              192.0.2.1 162 v3 priv trap Admin
                              -------------------------------------------------------------------
                              switch(config)# show snmp trap | grep link
                              link : linkDown Yes
                              link : linkUp Yes
                              link : extended-linkDown Yes
                              link : extended-linkUp Yes
                              link : cieLinkDown Yes
                              link : cieLinkUp Yes
                              link : cisco-xcvr-mon-status-chg Yes
                              switch(config)#

                              MIBs

                              Following is information about the supported SNMP MIBs.

                              To locate and download the MIBs, go to the following URL: http:/​/​www.cisco.com/​public/​sw-center/​netmgmt/​cmtk/​mibs.shtml.

                              • IF-MIB
                              • ENTITY-MIB
                              • CISCO-ENTITY-EXT-MIB-V1SMI
                              • CISCO-ENTITY-FRU-CONTROL-MIB
                              • BRIDGE-MIB
                              • CISCO-FLASH-MIB
                              • CISCO-SYSTEM-MIB
                              • CISCO-SYSTEM-EXT-MIB
                              • CISCO-FEATURE-CONTROL-MIB
                              • CISCO-CDP-MIB
                              • CISCO-VIRTUAL-NIC-MIB
                              • CISCO-PROCESS-MIB
                              • CISCO-SYSLOG-EXT-MIB
                              • CISCO-VLAN-MEMBERSHIP-MIB
                              • TCP-MIB
                              • UDP-MIB
                              • CISCO-PRIVATE-VLAN-MIB
                              • CISCO-SECURE-SHELL-MIB
                              • CISCO-IMAGE-UPGRADE-MIB
                              • CISCO-LICENSE-MGR-MIB
                              • RMON2-MIB
                              • CISCO-AAA-SERVER-MIB
                              • CISCO-AAA-SERVER-EXT-MIB
                              • CISCO-COMMON-MGMT-MIB
                              • CISCO-COMMON-ROLES-MIB
                              • CISCO-CONFIG-MAN-MIB
                              • CISCO-FTP-CLIENT-MIB
                              • CISCO-IMAGE-MIB
                              • CISCO-LAG-MIB
                              • CISCO-NOTIFICATION-CONTROL-MIB
                              • CISCO-NTP-MIB
                              • CISCO-RF-MIB
                              • CISCO-RMON-CONFIG-MIB
                              • CISCO-SMI
                              • CISCO-SNMP-TARGET-EXT-MIB
                              • NOTIFICATION-LOG-MIB
                              • IP-MIB
                              • SNMP-COMMUNITY-MIB
                              • SNMP-FRAMEWORK-MIB
                              • SNMP-MPD-MIB
                              • SNMP-NOTIFICATION-MIB
                              • SNMP-TARGET-MIB
                              • SNMP-USM-MIB
                              • SNMPv2-MIB

                              Feature History for SNMP

                              Feature Name

                              Releases

                              Feature Information

                              SNMP

                              4.0(4)SV1(1)

                              This feature was introduced.