Device and Sensor Setup > Sensor Settings

PRTG Manual: SNMP Custom Sensor

The SNMP Custom sensor monitors a single parameter that is returned by a specific object identifier (OID) via the Simple Network Management Protocol (SNMP).

SNMP Custom Sensor

For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.

Sensor in Other Languages

Dutch: SNMP (Klant specifiek)
French: SNMP personnalisé
German: SNMP (Benutzerdef.)
Japanese: SNMP カスタム
Portuguese: SNMP (customizado)
Russian: Пользовательские параметры SNMP
Simplified Chinese: SNMP 自定义
Spanish: SNMP (personalizado)

Remarks

It might not work to query data from a probe device via SNMP (querying localhost, 127.0.0.1, or ::1). Add this device to PRTG with the IP address that it has in your network and create the SNMP sensor on this device instead.
This sensor supports the IPv6 protocol.

This sensor has a very low performance impact.

See the Knowledge Base: How do I find out which OID I need for an SNMP Custom sensor?

Add Sensor

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the settings that are required to create the sensor. You can change nearly all settings on the sensor's Settings tab after creation.

OID Settings

Setting	Description
Channel Name	Enter a name for the channel in which the sensor shows the results for the OID. Enter a string. You can change this value later in the channel settings of this sensor.
Value Type	Select the expected numeric type of the results at the OID: Absolute (unsigned integer): Integers without an operational sign, such as 10 or 120. Absolute (signed integer): Integers with an operational sign, such as -12 or 120. Absolute (float): Float values, such as -5.80 or 8.23. Delta (counter): Counter values. PRTG calculates the difference between the last and the current value. PRTG additionally divides the delta value by a time period to indicate a speed value. This mode only works if the difference between the last and the current value is positive and increases with each scanning interval. This mode does not support negative values and decreasing values. PRTG shows this value for reference purposes only. If you need to change this value, add the sensor anew.
Unit String	Enter the unit for the values that this sensor returns. Enter a string. PRTG uses the unit string for display purposes and shows it in graphs, data tables, and gauges. If you want to change the unit after sensor creation, you can change it in the sensor's channel settings.

Setting

Description

Channel Name

Enter a name for the channel in which the sensor shows the results for the OID. Enter a string.

You can change this value later in the channel settings of this sensor.

Value Type

Select the expected numeric type of the results at the OID:

Absolute (unsigned integer): Integers without an operational sign, such as 10 or 120.
Absolute (signed integer): Integers with an operational sign, such as -12 or 120.
Absolute (float): Float values, such as -5.80 or 8.23.
Delta (counter): Counter values. PRTG calculates the difference between the last and the current value. PRTG additionally divides the delta value by a time period to indicate a speed value.
This mode only works if the difference between the last and the current value is positive and increases with each scanning interval. This mode does not support negative values and decreasing values.

PRTG shows this value for reference purposes only. If you need to change this value, add the sensor anew.

Unit String

Enter the unit for the values that this sensor returns. Enter a string. PRTG uses the unit string for display purposes and shows it in graphs, data tables, and gauges.

If you want to change the unit after sensor creation, you can change it in the sensor's channel settings.

Basic Sensor Settings

Click the Settings tab of a sensor to change its settings.

Basic Sensor Settings

Setting	Description
Sensor Name	Enter a name to identify the sensor.
Parent Tags	Shows tags that the sensor inherits from its parent device, parent group, and parent probe. This setting is for your information only. You cannot change it.
Tags	Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited. It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>). For performance reasons, it can take some minutes until you can filter for new tags that you added. The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor: snmpcustomsensor
Priority	Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority () to the highest priority ().

Usually, a sensor connects to the IP Address/DNS Name of the parent device. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings.

OID Settings

Setting	Description
OID	Enter the OID of the SNMP object that you want to receive numeric data from. Most OIDs begin with 1.3.6.1. However, OIDs that start with 1.0, or 1.1, or 1.2 are also allowed. If you want to entirely disable the validation of your entry, add the string norfccheck: to the beginning of the OID, for example, norfccheck:2.0.0.0.1.
Value Type	Shows the value type of the numeric data that this sensor receives from the OID. PRTG shows this value for reference purposes only. If you need to change this value, add the sensor anew.
Multiplication	If you want to multiply the received data with a certain value, enter the multiplier. Use the default value 1 to not change the received value. Enter an integer.
Division	If you want to divide the received data by a certain value, enter the divisor. Use the default value 1 to not change the received value. Enter an integer.
If Value Changes	Define what the sensor does when the sensor value changes: Ignore changes (default): Take no action on change. Trigger 'change' notification: Send an internal message indicating that the sensor value has changed. In combination with a change trigger, you can use this mechanism to trigger a notification whenever the sensor value changes.

Sensor Display

Setting	Description
Primary Channel	Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel is always displayed below the sensor's name. The available options depend on what channels are available for this sensor. You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.
Graph Type	Define how different channels are shown for this sensor: Show channels independently (default): Show a graph for each channel. Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic. You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).
Stack Unit	This setting is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Setting

Description

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel is always displayed below the sensor's name. The available options depend on what channels are available for this sensor.

You can set a different primary channel later by clicking below a channel gauge on the sensor's Overview tab.

Graph Type

Define how different channels are shown for this sensor:

Show channels independently (default): Show a graph for each channel.
Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic.
You cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all of these settings are inherited from objects that are higher in the hierarchy. We recommend that you change them centrally in the root group settings if necessary. To change a setting for this object only, click under the corresponding setting name to disable the inheritance and to display its options.

For more information, see section Inheritance of Settings.

Scanning Interval

For more information, see section Root Group Settings, section Scanning Interval.

Schedules, Dependencies, and Maintenance Window

You cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.

Schedules, Dependencies, and Maintenance Window

For more information, see section Root Group Settings, section Schedules, Dependencies, and Maintenance Window.

Access Rights

For more information, see section Root Group Settings, section Access Rights.

Channel List

Which channels the sensor actually shows might depend on the target device, the available components, and the sensor setup.

Channel	Description
Downtime	In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status in percent.
[Value]	The single numeric value (int64) for a specified OID This channel is the primary channel by default.

Channel

Description

Downtime

In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status in percent.

[Value]

The single numeric value (int64) for a specified OID

This channel is the primary channel by default.

Knowledge Base