The RADIUS v2 sensor monitors a Remote Authentication Dial-In User Service (RADIUS) server according to RFC 2865.

i_round_blueThe sensor tries to authenticate itself against the server. If authentication fails, the sensor shows the Down status.

RADIUS v2 Sensor

RADIUS v2 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: RADIUS v2
  • French: RADIUS v2
  • German: RADIUS v2
  • Japanese: RADIUS V2
  • Portuguese: RADIUS v2
  • Russian: RADIUS v2
  • Simplified Chinese: RADIUS v2
  • Spanish: RADIUS v2


Consider the following remarks and requirements for this sensor:



Performance impact

  • This sensor has a high performance impact. We recommend that you use no more than 200 of this sensor on each probe.

.NET 4.7.2 or later

  • This sensor requires .NET 4.7.2 or later from Microsoft on the probe system. In a cluster, install it on every cluster node.

i_round_redIf the framework is missing, you cannot create this sensor.

i_square_cyanFor more information, see the Knowledge Base: Which .NET version does PRTG require?

Plain text authentication

  • This sensor only supports plain text authentication (Password Authentication Protocol (PAP)).


  • This sensor only supports IPv4.


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

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:

  • radiussensor

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

RADIUS Specific

RADIUS Specific

RADIUS Specific



Timeout (Sec.)

Enter a timeout in seconds for the request. Enter an integer. The maximum timeout value is 900 seconds (15 minutes).

i_round_blueIf the reply takes longer than this value, the sensor cancels the request and shows a corresponding error message.

User Name

Enter the user name for the authentication against the RADIUS server. Enter a string.


Enter the password for the authentication between the client (the probe system) and the RADIUS server. Enter a string.

Shared Secret

Enter the shared secret for the authentication between the authenticator (the probe system) and the RADIUS server. Enter a string.


Enter the number of the port for the connection to the RADIUS server. The default value is 1812. Enter an integer.

NAS Identification

Define how to identify the network access server (NAS):

  • Use NAS IP address (default): Enter the NAS IP Address for identification below.
  • Use NAS identifier: Enter the NAS Identifier below.

NAS IP Address

This setting is only visible if you select Use NAS IP address (default) above.

Enter a valid IP address for the NAS that originates the access request.

NAS Identifier

This setting is only visible if you select Use NAS identifier above.

Enter an identifier for the NAS that originates the access request.

Result Handling

Define what PRTG does with the sensor result:

  • Discard result (default): 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 names are Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This setting is for debugging purposes. PRTG overwrites these files 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.

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.

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


The RADIUS code

  • Up status: Accept-Accept
  • Warning status: Access-Challenge
  • Down status: Access-Reject

i_round_blueThis channel is the primary channel by default.

Response Time

The response time


i_square_blueKNOWLEDGE BASE

Which .NET version does PRTG require?

What security features does PRTG include?