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SNMP v3 in Cisco IOS Devices

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    Name
    Jimmy Lai
    Twitter

The `Simple Network Management Protocol (SNMP) is an application layer protocol that collects and organizes device information in an IP network. SNMP pulling from the device is enabled on port 161. In addition, 162 must be open in order to send a trap from the device to the SNMP server.

SNMP TRAP AND V2C

The snmp-server enable traps* command activates traps for all notifications. If you want, you can enable trap for a specific incident based on your needs.

snmp-server host 192.168.2.181 version 2c cisco
snmp-server community cisco RO
snmp-server enable traps

RUN TEST - SHOW SNMP

First, execute show snmp from the device.

archie@lenovo (git)-[main] % snmpwalk -v2c -c cisco 1.2.1.2
SNMPv2-MIB::sysDescr.0 = STRING: Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.5(2)T, DEVELOPMENT TEST SOFTWARE
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Thu 26-Mar-15 07:36 by prod_rel+
SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.1
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (886297) 2:27:42.97
SNMPv2-MIB::sysContact.0 = STRING:

SNMP v3 in Cisco

SNMPv3 supports 3 modes

-l LEVEL set security level (noAuthNoPriv|authNoPriv|authPriv)

NOAUTHNOPRIV

This mode has no authentication and no encryption services.

snmp-server view VIEW mib-2 included
snmp-server group GROUP v3 noauth read VIEW
snmp-server user USER GROUP v3

snmpwalk -v3 -l authPriv -u USER -a sha -A 'cisco' -x AES128 -X 'cisco' r1

AUTHNOPRIV

In this mode, authentication will be there, but no encryption services.

snmp-server view OUR-MIB-VIEW mib-2 included
snmp-server group OUR-SNMP-GROUP v3 auth read OUR-MIB-VIEW
snmp-server user SNMPuser OUR-SNMP-GROUP v3 auth md5 cisco_AUTH

In this mode, authentication and encryption services will be there.

snmp-server view OUR-MIB-VIEW mib-2 included
snmp-server group OUR-SNMP-GROUP v3 auth read OUR-MIB-VIEW
snmp-server user SNMPuser OUR-SNMP-GROUP v3 auth md5 cisco_AUTH priv 3des cisco_PRIV

How to configure SNMPv3 in Cisco Nexus Devices

To configure the snmp v3, we only need to run below command.

snmp-server user SNMPuser auth sha cisco12345 priv aes-128 cisco12345