Monitors

PRTG Manual: Custom SNMP Checks

The SNMP monitor allows you to query custom attributes from the device using SNMP and compare them to an expected result.

Configuring the Monitor

The Port monitor editor contains the following tabs that require configuration: Settings, Devices, Schedule, Event, and History.

The Schedule, Events and History settings are the same for all monitor types. See Configuring Monitors for more information about configuring these settings. For the settings tab see the information below.

Settings

Name

The Monitor name is the name used to refer to the monitor in the monitors list view, and in monitor events and notifications. Monitor names need not be unique, but it is recommended that you use unique names to differentiate them.

SNMP OID Checks

The SNMP OID Checks section is a list of the OIDs that the monitor will query.

Adding an OID

To add an OID press the add button. An editor allowing you to configure the OID entry is displayed. Once configured press the save button and the OID is added to the list.

Editing a Port

To edit an OID double click the OID in the list (or press the edit button ). The configuration editor is displayed. To save the changes press the save button and the changes are applied.

Deleting a Port

To delete an OID select the OID in the list and press the delete button . The OID entry will be removed from the list.

Configuring an OID entry

An OID entry contains the following settings

OID

The OID to request from the SNMP agent on the device. Within SNMP an OID is basically a unique identifier for a value stored on the device. To select an OID by browsing the device’s OID structure, select the browse button to the right of the OID editor. The SNMP MIB walker will appear, and it will allow you to browse and select an OID from a selected device. Once selected the OID value will be placed in the OID editor. See SNMP MIB Walker for more information.

Name

Name is a description of the OID value.

Use Expected Value

If you select Use Expected Value, the monitor will compare the SNMP response with the value you specify in the Expected Value field. By default, the monitor will check that the SNMP response value equals the expected value. However, if you check the Verify Not Equal box, the monitor will check that the SNMP response value does not equal the expected value.

Use Thresholds

Use Thresholds can be used with numeric OID responses to ensure that the value of the response does not exceed the specified Warning and Critical levels. If the value exceeds the Warning level, the monitor will report the Warning state. If the value exceeds the Critical level, the monitor will report the Down state. (The Critical value should be greater than or equal to the Warning value.)

If you check the Alert When Less Than box, the monitor will work in the opposite direction. That is, it will ensure that the value of the response does not go lower than the specified Warning and Critical levels. If the value goes below the Warning level, the monitor will report the Warning state. If the value goes below the Critical level, the monitor will report the Down state. (In this case, the Critical value should be less than or equal to the Warning value.)

Devices

The devices tab allows you to select which devices will be monitored. To add devices to the monitor select the button in the lower left corner. A device selector will be presented allowing you to choose one or more devices to monitor. To remove a device from the monitor select it in the grid and press the delete button .