<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: MQTT Round Trip Sensor

The MQTT Round Trip sensor monitors the availability of a Message Queue Telemetry Transport (MQTT) broker (server), connects to the broker as a publishing and subscribing client, and sends the data packets using a predefined topic.

MQTT Round Trip Sensor

MQTT Round Trip Sensor

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: MQTT Heen en Terug
  • French: MQTT aller-retour
  • German: MQTT Round Trip
  • Japanese: MQTT ラウンドトリップ
  • Portuguese: Ida e volta MQTT
  • Russian: Цикл MQTT
  • Simplified Chinese: MQTT 往返
  • Spanish: Ida y vuelta MQTT


Consider the following remarks and requirements for this sensor:




  • This sensor requires credentials for MQTT.


  • This sensor supports IPv6.

Performance impact

  • This sensor has a low performance impact.

New framework

  • This sensor was converted to a new framework. MQTT Round Trip sensors that were added before PRTG 20.2.59 do not work anymore. We recommend that you pause existing sensors to keep their historic data. To continue monitoring, please add a new MQTT Round Trip sensor.


  • This sensor uses lookups to determine the status values of one or more channels.

Multi-platform probe

  • You can add this sensor to a multi-platform probe.

Basic Sensor Settings

Basic Sensor Settings

Basic Sensor Settings

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

  • mqtt
  • mqttroundtrip
  • roundtrip

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

MQTT Specific

MQTT Specific

MQTT Specific




Enter the topic for the round trip. The default is PRTG/roundtrip/%sensorid.

i_round_bluePRTG replaces %sensorid with the sensor's ID.

Connection Settings

Define the connection settings for the connection to the MQTT broker:

  • Use default settings: Use the default connection settings.
  • Use custom settings: Use a ClientID that you can specify below.


This setting is only visible if you select Use custom settings above.

Enter the ClientID for the connection to the MQTT broker. The default is PRTG_%sensorid.

i_round_bluePRTG replaces %sensorid with the sensor's ID. For the subscribing client, PRTG automatically adds _subscriber to the ClientID. For the publishing client, PRTG automatically adds _publisher to the ClientID.

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, 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.

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 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.
    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 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

Debug Options

Debug Options



Result Handling

Define what PRTG does with the sensor result:

  • Discard result: Do not store the sensor result.
  • Store result: Store the last sensor result 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.

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

i_round_blueIn 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 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.

Channel List

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




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

Publisher Connection Time

The time it takes the publisher to connect

Round Trip Time

The RTT of the message (after both publisher and subscriber connect)

i_round_blueThis channel is the primary channel by default.


The round trip status

  • Up status: Roundtrip Complete
  • Down status: Message Not Received, Message Not Sent, Publisher Could Not Connect, Subscriber Could Not Connect

Subscriber Connection Time

The time it takes the subscriber to connect


i_square_blueKNOWLEDGE BASE

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