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PRTG Manual: SNMP RMON v2 Sensor

The SNMP RMON v2 sensor monitors a network switch port of the target system using Simple Network Management Protocol (SNMP) and the Remote Network Monitoring (RMON) Management Information Base (MIB) standard.

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

Sensor in Other Languages

Dutch: SNMP RMON v2
French: SNMP RMON v2
German: SNMP RMON v2
Japanese: SNMP RMON v2
Portuguese: SNMP RMON v2
Russian: SNMP RMON v2
Simplified Chinese: SNMP RMON v2
Spanish: SNMP RMON v2

Remarks

Consider the following remarks and requirements for this sensor:

Remark	Description
Credentials	This sensor requires credentials for SNMP in settings that are higher in the object hierarchy.
IPv6	This sensor supports IPv6.
Performance impact	This sensor has a very low performance impact.
SNMP compatibility options	This sensor supports 32-bit and 64-bit counters. Select which counters the sensor uses in the SNMP compatibility options setting inherited from the parent device.
Meta-scan	This sensor uses the meta-scan feature. After sensor creation, some settings might appear for reference purposes only.
Knowledge Base	Knowledge Base: What value does the Transmitted channel of an RMON sensor show? Knowledge Base: Where is the volume line in graphs?

Add Sensor

During sensor creation, PRTG performs a meta-scan of the target device. In the table with the meta-scan results, select the port that you want to monitor.

The sensor monitors one port only. If you select multiple ports, PRTG creates one sensor for each port.

You cannot change the port after sensor creation in Specific Sensor Settings. You can only update the Description field in case the port table of the device changes.

Basic Sensor Settings

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

rmonsensor
snmp
snmprmon
snmprmonsensor

For more information about basic sensor settings, see section Sensor Settings.

Specific Sensor Settings

Setting	Description
Description	Shows the port identifier that the sensor monitors. The identifier is found in the ifTable under ifDescr. PRTG determines this value during the meta-scan and shows it for reference purposes only. If the device port table changes after sensor creation, the sensor might enter the Down status. You might need to manually change this setting. Click the lock icon to edit this setting. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.
64-Bit	If the interface that this sensor monitors uses 64-bit counters. PRTG determines this value during the meta-scan and shows it for reference purposes only. If the device 64-bit capabilities change after sensor creation, the sensor might enter the Down status. This is because the sensor expects one type of counter and process the other counter type. You might need to manually change this setting. Click the lock icon to edit this setting. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.

Setting

Description

Shows the port identifier that the sensor monitors. The identifier is found in the ifTable under ifDescr. PRTG determines this value during the meta-scan and shows it for reference purposes only.

If the device port table changes after sensor creation, the sensor might enter the Down status. You might need to manually change this setting. Click the lock icon to edit this setting. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so.
Wrong usage can result in incorrect monitoring data.

64-Bit

If the interface that this sensor monitors uses 64-bit counters. PRTG determines this value during the meta-scan and shows it for reference purposes only.

If the device 64-bit capabilities change after sensor creation, the sensor might enter the Down status. This is because the sensor expects one type of counter and process the other counter type. You might need to manually change this setting. Click the lock icon to edit this setting. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so.
Wrong usage can result in incorrect monitoring data.

Sensor Display

Setting	Description
Primary Channel	Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel 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 this sensor shows different channels: 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 select Stack channels on top of each other above. Select a unit from the list. PRTG stacks all channels with this unit 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, PRTG displays the last value of the primary channel 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 this sensor shows different channels:

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 select Stack channels on top of each other above.

Select a unit from the list. PRTG stacks all channels with this unit 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.

Debug Options

Setting	Description
Result Handling	Define what PRTG does with the sensor result: Discard result (default): Do not store the sensor result. Store result: Store the sensor result and the last response in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file name is Result of Sensor [ID].log. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval. This option is not available when the sensor runs on the hosted probe of a PRTG Hosted Monitor instance. In a cluster, PRTG stores the result in the PRTG data directory of the master node.

Setting

Description

Result Handling

Define what PRTG does with the sensor result:

Discard result (default): Do not store the sensor result.
Store result: Store the sensor result and the last response in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file name is Result of Sensor [ID].log. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval.

This option is not available when the sensor runs on the hosted probe of a PRTG Hosted Monitor instance.

In a cluster, PRTG stores the result in the PRTG data directory of the master node.

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.

Channel List

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

Channel	Description
Broadcast Packets	The number of broadcast packets
Collisions	The number of collisions
CRC Errors	The number of CRC errors
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.
Drop Events	The number of drop events
Fragments	The number of fragments
Jabbers	The number of jabbers
Multicast Packets	The number of multicast packets
Oversize Packets	The number of oversize packets
Packets	The number of packets
Packets 1024 - 1518 Bytes	The number of packets with 1024 - 1518 bytes
Packets 128 - 255 Bytes	The number of packets with 128 - 255 bytes
Packets 256 - 511 Bytes	The number of packets with 256 - 511 bytes
Packets 512 - 1023 Bytes	The number of packets with 512 - 1023 bytes
Packets 64 Bytes	The number of packets with 64 bytes
Packets 65 - 127 Bytes	The number of packets with 65 - 127 bytes
Transmitted	The transmitted bytes This channel is the primary channel by default.
Undersize Packets	The number of undersize packets

KNOWLEDGE BASE

What security features does PRTG include?

https://helpdesk.paessler.com/en/support/solutions/articles/76000062446

My SNMP sensors don’t work. What can I do?

https://helpdesk.paessler.com/en/support/solutions/articles/76000041708

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