<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: System Administration—Monitoring

To open system administration, select Setup | System Administration from main menu. Click on the tabs to change the different settings.

System Administration Bar

System Administration Bar

You can define the following aspects of your PRTG system setup:

In the monitoring settings you can define global values regarding scanning intervals, unusual and similar sensors detection, auto-discovery, and uptime threshold.

Note: If you open this system administration page from another administration page and 15 minutes (900 seconds) have passed since your last credential based login, you have to provide your credentials again for security reasons. A dialog box will appear. Enter your Login Name and Password for PRTG in the corresponding fields and click on the Login button. You can continue with your task immediately.

Monitoring Settings

Note: This documentation refers to the PRTG System Administrator user accessing the Ajax interface on a master node. For other user accounts, interfaces, or nodes, not all of the options might be available as described. When using a cluster installation, failover nodes are read-only by default.

Scanning Intervals

Available Intervals

Define the intervals available in the drop down list of every object's settings. In the text field, enter one value in each line. Use s, m, h, and d for defining seconds, minutes, hours, and days. By default, there are following scanning intervals defined:

30s: 30 seconds

1m: 1 minute

5m: 5 minutes

10m: 10 minutes

15m: 15 minutes

30m: 30 minutes

1h: 1 hour

4h: 4 hours

6h: 6 hours

12h: 12 hours

1d: 1 day

Note: We recommend not to use intervals shorter than 10 seconds to prevent system overload. Intervals below 10 seconds are not officially supported! The maximum supported scanning interval is 10 days.

Unusual Detection

The unusual detection can set sensors to an Unusual status when there are values that are untypical for the time span they're measured in, compared to historic monitoring results. When disabled (both settings to Never), sensors will never be shown as unusual. Note: You can enable and disable unusual detection for any object (e.g. for a device, or an entire group) in the Object Settings.

Show Unusual When

Define when a sensor will be shown as unusual, comparing the weekday. Choose between:

  • Never: Disable unusual detection for weekday average.
  • 24h average is <80% or >120% of weekday average
  • 24h average is <50% or >200% of weekday average
  • 24h average is <20% or >500% of weekday average (recommended)
  • 24h average is <10% or >1,000% of weekday average
  • 24h average is <1% or >10,000% of weekday average

Show Unusual When

Define when a sensor will be shown as unusual, comparing the hour-of-day. Choose between:

  • Never: Disable unusual detection for hour-of-day average.
  • 24h average is <80% or >120% of hour-of-day average
  • 24h average is <50% or >200% of hour-of-day average
  • 24h average is <20% or >500% of hour-of-day average (recommended)
  • 24h average is <10% or >1,000% of hour-of-day average
  • 24h average is <1% or >10,000% of hour-of-day average


Define if unusual events will be written to the log file. Choose between:

  • Do not log unusual events
  • Write unusual events into the log

Similar Sensors Detection

Similar sensors detection enables PRTG to analyze sensor data for similarities. The detection will run in the background with low priority. The recommended setting for similar sensors detection is to let PRTG automatically decide how many channels will be analyzed. However, you can also override this setting. Note: When similar sensors analysis is turned off or you have exceeded 1,000 sensors and have chosen the automatic analysis depth option, the similar sensors entry will not be shown in the main menu bar.

Analysis Depth

Define the number of channels PRTG will analyze to detect similarities between sensors or turn the analysis off. Choose between:

  • Manage automatically based on sensor count (recommended): The analysis depth depends on the total number of sensors you have configured. PRTG will analyze all channels for up to 500 sensors, and only the primary sensor channels for up to 1,000 sensors. If exceeding 1,000 sensors, the analysis will be turned off.
  • Analyze primary channels only: Only the primary channels of sensors are analyzed. Be aware of potentially high CPU load of PRTG when choosing this setting for more than 1,000 sensors.
  • Analyze all channels (higher CPU load): Similarity detection is applied to all channels. Be aware of potentially high CPU load of PRTG when choosing this setting for more than 500 sensors.
  • Turn analysis off: No similarity detection takes place. Choose this option if you are not interested in the analysis results or you want to keep PRTG's CPU load at a minimum.

Recommended Sensors Detection

With the sensor recommendation service, you can automatically analyze the devices which you add to PRTG for useful but missing sensors. PRTG can show you sensor types that give you a much more detailed picture about your network when you monitor the respective devices with them. The analysis runs with low priority in background when you add a new device, the last analysis has been 30 days ago, or you click Recommend Now in the context menu of a device or on a device overview tab.

When the analysis is finished for a device, suggested sensor types appear in the Recommended Sensors table list on the device overview tab. You can add them directly to the device with the Add Sensors button.

Note: To recommend SNMP sensors for a device, the recommendation service uses the SNMP version that you define in the Credentials for SNMP Devices section of the device settings.

Note: The recommended sensors detection cannot run at the same time as Auto-Discovery. PRTG gives auto-discovery a higher priority, for example, when you add a new device, and queues the sensor recommendation in this case.

Note: The recommendation service only checks if a certain sensor type currently exists on a device and recommends to add this sensor if not found. It does not check if there already existed a sensor of this type on the device and was deleted previously! Because of this, sensor types appear in the "Recommended Sensors" list again if they are categorized as useful for the according device when you have deleted all sensors of this type.

Detection Engine

Define if you want PRTG to analyze your devices to recommend useful sensor types. Choose between:

  • Suggest recommended sensors (recommended): PRTG analyzes your devices automatically to recommend useful sensor types. We recommend you to set this option to not miss any important data about your network.
    Note: You can manually start the analysis for a device with Recommend Now in the context menu or on the overview tab.
  • Turn recommendations off: PRTG does not recommend sensors. Select this option if you have issues with the performance of PRTG or do not want to see this information on device overview tabs. Also you will not have the option Recommend Now in device context menus or on overview tabs.

Auto-Discovery Settings

Run Discovery at

Define the time when PRTG automatically runs an Auto-Discovery in your network if you configured a daily or weekly Discovery Schedule in the auto-discovery group settings. Choose a full hour between 0:00 and 23:00. We recommend you to choose a time when there is little user activity in your network, because auto-discoveries can produce a certain amount of load.

Uptime Threshold

Desired Minimum Uptime

Define which uptime in percent PRTG regards as 100 percent. This setting affects the colors shown next to the sensor icons in reports. Select one of the predefined values between 90 % and 99.999 %.

Click on the Save button to store your settings. If you change tabs or use the main menu, all changes to the settings will be lost!


Knowledge Base: How can I speed up PRTG—especially for large installations?

Knowledge Base: How and where does PRTG store its data?





There are some settings that you have to make in the PRTG Administration Tool, available as native Windows application. For more details, please see sections: