The SNMP RMON sensor monitors traffic on a device using the Remote Monitoring (RMON) standard via the Simple Network Management Protocol (SNMP).

i_round_blueYou can create it on an SNMP-compatible device that provides traffic data via RMON. Depending on the data that the device returns, PRTG displays traffic data for each port in different channels, which allows a detailed analysis. If available, the sensor queries 64-bit counters.



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

Sensor in Other Languages

  • Dutch: SNMP RMON
  • French: RMON (SNMP)
  • German: SNMP RMON
  • Japanese: SNMP RMON
  • Portuguese: RMON (SNMP)
  • Russian: RMON по SNMP
  • Simplified Chinese: SNMP RMON
  • Spanish: RMON (SNMP)


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.

i_round_blueThe settings that you select in the Add Sensor dialog are valid for all sensors that you create when you finish the dialog.

RMON Specific




Select the ports that you want to monitor. PRTG creates one sensor for each port that you select.

i_round_blueEnable 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.

i_round_blueYou can select interfaces and cancel the selection by clicking Select all connected interfaces, Select all disconnected interfaces, and Deselect all interfaces.

Basic Sensor Settings

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

Basic Sensor Settings

Basic Sensor Settings



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.

i_round_blueThis setting is for your information only. You cannot change it.


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.

i_round_blueIt is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>).

i_round_blueFor 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:

  • snmprmon


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 (i_priority_1) to the highest priority (i_priority_5).

i_round_blueUsually, 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.

RMON Specific

RMON Specific

RMON Specific




Shows the number of the interface port that this sensor monitors.

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

Channel Mask

Describes which channels are available and might be useful for the Paessler support team.

i_round_blueThis setting is for your information only. You cannot change it.

Sensor Display

Sensor Display

Sensor Display



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.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary 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.
    i_round_redYou 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 b_inherited_enabled under the corresponding setting name to disable the inheritance and to display its options.

i_square_cyanFor more information, see section Inheritance of Settings.

Scanning Interval

Scanning Interval

Scanning Interval

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

Schedules, Dependencies, and Maintenance Window

i_round_blueYou 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

Schedules, Dependencies, and Maintenance Window

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

Access Rights

Access Rights

Access Rights

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

Channel Unit Configuration

i_round_blueWhich channel units are available depends on the sensor type and the available parameters. If no configurable channels are available, this field shows No configurable channels.

Channel Unit Configuration

Channel Unit Configuration

i_square_cyanFor more information, see section Root Group Settings, section Channel Unit Configuration.

Channel List

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



Broadcast Packets

The number of broadcast packets per second


The number of collisions per second

CRC Errors

The number of cyclic redundancy check (CRC) errors per second


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.

Drop Events

The number of drop events per second


The number of fragments per second


The number of jabbers per second

Multicast Packets

The number of multicast packets per second

Oversize Packets

The number of oversize packets per second


The number of packets per second

Packets <= 64 Byte

The number of packets with less than or equal to 64 bytes per second

Packets 65 - 127 Bytes

The number of packets with 65 - 127 bytes per second

Packets 128 - 255 Bytes

The number of packets with 128 - 255 bytes per second

Packets 256 - 511 Bytes

The number of packets with 256 - 511 bytes per second

Packets 512 - 1023 Bytes

The number of packets with 512 - 1023 bytes per second

Packets 1024 - 1518 Bytes

The number of packets with 1024 - 1518 bytes per second


The transmitted bytes per second

i_round_blueThis channel is the primary channel by default.

Undersize Packets

The number of undersize packets per second


i_square_blueKnowledge Base

What value does the Transmitted channel of an RMON sensor show?

SNMP Traffic sensors when the device changes them

Where is the volume line in graphs?

What security features does PRTG include?

What SNMP sensors does PRTG offer?

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