PRTG Manual: SNMP Custom Table Sensor
The SNMP Custom Table sensor monitors entries from a table that is provided via Simple Network Management Protocol (SNMP). You can create one new sensor per table row. For each sensor, you can define up to ten channels. Each channel shows the value of one defined table column.
- It can show numerical values in up to 10 channels per table row.
Which channels the sensor actually shows might depend on the monitored device and the sensor setup.
The SNMP Library sensor will automatically create SNMP Custom Table sensors when the imported Management Information Base (MIB) file contains tables.
Dutch: SNMP Aangepaste Tabel, French: Table SNMP personnalisée, German: SNMP (Benutzerdef. Tabelle), Japanese: SNMP カスタムテーブル, Portuguese: Tabela customizada do SNMP, Russian: Нестандартная таблица SNMP, Simplified Chinese: SNMP 自定义表, Spanish: Tabla de SNMP personalizado
- 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.
- Knowledge Base: How do I find out what OID I need to use for a custom sensor?
- Knowledge Base: What can I monitor with the SNMP Custom Table Sensor?
- For a general introduction to the technology behind SNMP, see section Monitoring via SNMP.
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.
PRTG will create one SNMP Table sensor for each table row that you select in the Add Sensor dialog. The settings you choose will be valid for all sensors that you create when you finish this dialog.
The following settings for this sensor differ in the Add Sensor dialog in comparison to the sensor's Settings tab.
Snmp Table |
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Table OID |
Enter the OID of the SNMP table you want to monitor. The OID needs to point directly to an object that represents an SNMP table. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.
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Basic Sensor Settings |
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Sensor Name |
Enter a meaningful name to identify the sensor. You can use the placeholders [tablename] and [rowidentifier]. They will be replaced with the name of the table and the identifying value of the chosen row respectively. You can choose 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 is not contained in the current table. The same index as in the original table will be added to the OID. |
Table Specific |
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Table |
Choose the relevant table rows in which you find the data that you want to monitor. You see a list with the names of all items that are available to monitor. Add check marks in front of the respective lines to select the desired items. PRTG creates one sensor for each selection. You can also use the check box in the table head to select and deselect all items. PRTG shows you the table that the OID you entered before returns. To better find what you want to monitor, especially in large tables, use the search function in the upper-right corner. |
Identification Column |
Define the identification column for the SNMP Table sensor(s) you want to create. The sensor uses this column to uniquely identify each table row. This column should preferably be unique because it will allow the sensor to keep track of changing indexes. The value of the column that you choose as the identification column will replace the [rowidentifier] in the sensor name. This allows you to distinguish sensors that are created for the same SNMP table.
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Sensor Channel #2 – #10 |
You can create up to 10 different sensor channels for this sensor. You have to define at least one data channel, so you will see all available settings for Sensor Channel #1 without enabling it manually. Additionally you can define Sensor Channel #2 up to Sensor Channel #10. To do so, choose between:
It is not possible to enable or disable sensor channels after the creation of this sensor!
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Value Type |
Select the expected type of the results in this channel. Choose between:
See below for the other channel settings that can be changed also after the sensor has been created.
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On the details page of a sensor, click the Settings tab to change its settings.
Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. See below for details on available settings.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful 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. |
Parent Tags |
Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here. |
Tags |
Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value. You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.
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Priority |
Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority). |
Snmp Table |
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Table OID |
Shows the OID of the SNMP table that this sensor monitors. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew. |
Table Specific |
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Identifier |
This is the value of the column that you selected as the Identification Column during the sensor creation. It is also displayed 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 the identification column. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew. |
Sensor Channel #x Name |
Enter a name for the channel in which the sensor shows the desired result. Please enter a string. |
Sensor 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. |
Sensor Channel #x Value Type |
Shows the value type of the data that this sensor receives in this channel. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew. |
Sensor Channel #x Unit |
Define the unit of the data that this sensor receives in this channel. Choose between:
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Sensor Channel #x Custom Unit |
This setting is only visible if you select the Custom unit option above. Define a unit for the channel value. Please enter a string. |
Sensor Channel #x Value Lookup |
This setting is only visible if you select the Value Lookup option above. Select a lookup file that you want to use with this channel. |
Sensor Channel #x+1 |
Shows if you enabled or disabled a channel. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew. |
Sensor Display |
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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 will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.
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Graph Type |
Define how different channels will be shown for this sensor.
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Stack Unit |
This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be 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. |
By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.
Scanning Interval |
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Click |
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Scanning Interval |
Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations. |
If a Sensor Query Fails |
Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:
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Schedules, Dependencies, and Maintenance Window |
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Schedule |
Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.
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Maintenance Window |
Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a Paused status instead. Choose between:
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Maintenance Begins |
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance Ends |
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window. |
Dependency Type |
Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:
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Dependency |
This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend. |
Dependency Delay (Sec.) |
Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.
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Access Rights |
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Click |
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User Group Access |
Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:
You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.
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Knowledge Base: What can I monitor with the SNMP Custom Table Sensor?
Knowledge Base: How to monitor a no-break (UPS) device complying to the UPS-MIB (RFC 1628)
Knowledge Base: How do I find out what OID I need to use for a custom sensor?
Knowledge Base: What SNMP sensors does PRTG offer?
Knowledge Base: My SNMP sensors don't work. What can I do?
To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see the Sensor Channel Settings section.
Click the Notification Triggers tab to change notification triggers. For detailed information, see the Sensor Notification Triggers Settings section.
For more general information about settings, see the Object Settings section.
For information about sensor settings, see the following sections: