PRTG Manual: SNMP Custom Table Sensor

Table OID

Enter the object identifier (OID) of the SNMP table that you want to monitor. The OID must directly point to an object that represents an SNMP table. PRTG creates one SNMP Custom Table sensor for each table row that you select.

If you do not enter an OID, you cannot proceed with channel creation.

Sensor Name

Enter a meaningful name to identify the sensor. You can use the placeholders [tablename] and [rowidentifier]. PRTG replaces them with the name of the table and the identifying value of the chosen row respectively. You can select the column that provides the row identifier in the Identification Column option below.

You can also enter a valid OID that is part of a different SNMP table, for example, [1.3.6.1.2.1.2.2.1.2], to query information that the current table does not contain. PRTG adds the same index as in the original table to the OID.

Table

The sensor shows you the table that the OID returns. Select the table rows that contain the data that you want to monitor. PRTG creates one sensor for each table row that you select.

Enable check boxes in front of the respective lines to select the items. Use the check box in the table header to select all items or to cancel the selection. In large tables, use the search function in the upper-right corner.

Identification Column

Define the identification column for the sensors that you want to create. The sensors use this column to uniquely identify each table row.

We recommend that you use a unique identification column because it allows the sensors to keep track of changing indexes.

The value of the column that you select as identification column replaces the [rowidentifier] in the sensor name. This lets you distinguish sensors that you create for the same SNMP table.

Channel #2 - #10

You can define up to 10 channels. You must define at least one data channel, so you see all available settings for Channel #1. Specify how to handle all other possible channels:

▪Disable: Do not create this channel.

▪Enable: Create this channel.

It is not possible to enable or disable channels after sensor creation.

All channels that you define during the creation of an SNMP Custom Table sensor are the same for all sensors for each table row.

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.

Absolute (float) and Delta (counter) are not compatible with the unit Lookup.

See below for other channel settings that you can also change after sensor creation.

This sensor monitors numeric values only. Make sure that you do not select columns that return strings because they lead to the Down status. For example, if you monitor an ifTable, we recommend that you do not select an ifDescr column because this results in an error.

Sensor Name

Enter a name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.

If the name contains angle brackets (<>), PRTG replaces them with braces ({}) for security reasons. For more information, see the Knowledge Base: What security features does PRTG include?

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

▪snmpcustomtable

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 ().

Table OID

Shows the OID of the SNMP table that this sensor monitors.

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

Identifier

This is the value of the column that you selected as the Identification Column during sensor creation. PRTG also displays it in the sensor name to distinguish it from other sensors you created for the same table with other table rows. You can change the identifier if you want to.

Identification Column

Shows the table column that you chose as identification column.

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

Channel #x Name

Enter a name for the channel in which the sensor shows the desired result. Enter a string.

Channel #x Column

Select the table column that, together with the table row, points to the value that you want to monitor in this channel. You can choose between the available columns of the table that you monitor.

Channel #x Value Type

Shows the value type of the data that this sensor receives in this channel.

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

Channel #x Unit

Define the unit of the data that this sensor receives in this channel:

▪BytesBandwidth

▪BytesMemory

▪BytesDisk

▪Temperature

▪Percent

▪TimeResponse

▪TimeSeconds

▪TimeHours

▪Count

▪CPU

▪BytesFile

▪SpeedDisk

▪SpeedNet

▪Custom

▪Lookup

For more information about the available units, see section Custom Sensors.

To use lookups with this channel, select Lookup and define the lookup file in Channel #x Lookup. Do not use Custom if you use lookups with this sensor.

You cannot use the unit Lookup if you select the value type Delta (counter) or Absolute (float). You are not able to create the sensor in this case.

Channel #x Custom Unit

This setting is only visible if you select the channel unit Custom above. Define a unit for the channel value. Enter a string.

Channel #x Lookup

This setting is only visible if you select the channel unit Lookup above. Select a lookup file that you want to use with this channel.

Channel #2 - #10

Shows if the channel is enabled or disabled.

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

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.

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

[Value]

The returned numeric values in up to ten channels per table row