If you're monitoring bandwidth usage on your switches or routers using MRTG, you can have Nagios alert you when traffic rates exceed thresholds you specify. Tip: You can usually find the OIDs that can be monitored on a switch by running the following command (replace 192.168.1.253 with the IP address of the switch): There are a million things that can be monitored via SNMP, so its up to you to decide what you need and want to monitor.

That's it for the SNMP monitoring example. The '-m RFC1213-MIB' is optional and tells the check_snmp plugin to only load the 'RFC1213-MIB' instead of every single MIB that's installed on your system, which can help speed things up.

The '-r 1' option tells the check_snmp plugin to return an OK state if '1' is found in the SNMP result (1 indicates an 'up' state on the port) and CRITICAL if it isn't found. In the example above, the '-o ifOperStatus.1' refers to the OID for the operational status of port 1 on the switch. If you want to ensure that a specific port/interface on the switch is in an up state, you could add a service definition like this:Ĭheck_command check_snmp!-C public -o ifOperStatus.1 -r 1 -m RFC1213-MIB In the check_command directive of the service definition above, the '-C public' tells the plugin that the SNMP community name to be used is 'public' and the '-o sysUpTime.0' indicates which OID should be checked. Use generic-service Inherit values from a templateĬheck_command check_snmp!-C public -o sysUpTime.0 If it doesn't, skip this section.Īdd the following service definition to monitor the uptime of the switch. If your switch or router supports SNMP, you can monitor a lot of information by using the check_snmp plugin.

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