<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Notifications Based on Sensor Limits Step by Step

i_round_blueThis documentation refers to an administrator that accesses the PRTG web interface on a master node. Other user accounts, interfaces, or failover nodes might not have all of the options in the way described here. In a cluster, note that failover nodes are read-only by default.

This section gives you an example of how to set up a notification for exceeded disk free limits. Take the following steps to set up notifications based on limits:

  • Step 1: Provide necessary information about the delivery of notifications (Simple Mail Transfer Protocol (SMTP) and SMS).
  • Step 2: Specify the recipients of notifications for each user account.
  • Step 3: Specify the notification methods and content to create the actual notifications.
  • Step 4: Define limits that change a sensor's status (this is not necessary for every kind of notification).
  • Step 5: Add suitable triggers to objects that trigger notifications if there is an issue in your network.
  • Step 6: Test if PRTG correctly triggers and delivers the created notifications.

Step 1: Set up Notification Delivery Settings

Before you can create actual notifications, you have to define how PRTG delivers the notifications to your email account, mobile phone, or pager. To do so, select Setup | System Administration | Notification Delivery from the main menu bar. Specify the mechanism for SMTP delivery, the sender email address and name, as well as the HELO ident. For SMS delivery, select your service provider and enter the corresponding credentials.

i_square_cyanFor more information, see section Notification Delivery.

i_podThis only applies to PRTG on premises installations, not to PRTG Hosted Monitor instances.

Step 2: Set up Notification Contacts

Create notification contacts to define how you want to receive notifications. Recipients can be email addresses, phone numbers (only available for PRTG on premises), or push devices (Android or iOS devices with the corresponding PRTG app).

You can define as many recipients as you want for each user account. By default, the recipient Primary Email Address is available. This is the email address that you provide in your account settings.

i_square_cyanFor more information, see section Notification Contacts.

Step 3: Specify Notification Methods and Content

To get an informative message when a disk is running out of free space, create a corresponding notification:

  1. Select Setup | Account Settings | Notification Templates from the main menu bar.
  2. Hover over b_add and click Add Notification Template.
  3. Enter a meaningful name for the notification template, for example, Disk Free Limit Notification.
    i_round_blueIf you want to trigger this notification on a global level, for example for a probe or group, so that it does not only apply to breached disk free limits, a general name might be more suitable (like the predefined notification Email to Admin, for example).
  4. You can optionally create a Schedule to activate notifications only at specific times, for example, only on weekdays. In section Notification Summarization, you can choose from various options to avoid message floods. Furthermore, you can define the User Group Access to this notification.
  5. Select a notification method. In this case, enable b_notification_disabled next to Send Email.
Create an Email Notification

Create an Email Notification

i_square_cyanYou can select any other notification method, of course. For more information, see section Notification Templates.

  1. Specify who receives a notification, for example, select a specific user and PRTG sends the notification to all notification contacts that you defined for this user account in step 2.
  2. Enter the Subject of the email notification or use the predefined placeholders.
    i_square_cyanFor available placeholders, see section List of Placeholders for Notifications.
  3. Specify the Format and the Priority of the notification.
  4. Click Create. PRTG opens the Notifications Templates tab.

You can now use the new notification for every trigger on every object in your device tree.

Step 4: Define Limits

Before you create triggers that initiate notifications, you need to specify the limits that you want to apply to your disks. For example, if you want to get a notification when a disk has exceeded 80% of its capacity, set the sensor to the Warning status if it reaches this limit. You have the following options to set limits for disk free sensors:

i_round_blueYou can also use the multi-edit functionality to set limits for multiple sensors at once.

Step 4.1: Define Limits in Sensor Settings (Multi-Disk Free Sensors Only)

You can set limits for sensors that monitor multiple disks directly via the sensor's Settings tab. Multi-edit for sensors is also possible.

Set Limits for All Disks in the Sensor Settings

Set Limits for All Disks in the Sensor Settings

  1. Open the settings of the selected sensor and go to section Set Limits Checked For ALL Disks.
  2. Enable Use the limits of both the sensor and the channel settings.
  3. In the field Lower Warning Limit, enter the percentage that suits your needs. In our example, this is 20. This limit applies to all channels of the selected sensors that represent disks.
    i_round_blueAlternatively, you can use bytes to define a limit. However, we recommend that you use percentage values for more flexibility.
  4. Click Save to save your settings.

Step 4.2: Define Limits in Channel Settings

To set specific limits for single disks, use the sensors' channel settings. You can open the channel settings via b_channel_settings below the channel gauge or via b_channel_settings_2 in the channels table.

Set Limits in the Channel Settings

Set Limits in the Channel Settings

  1. Under Limits, select Enable alerting based on limits.
  2. Enter the desired Lower Warning Limit. This limit only applies to the respective channel.
  3. Click OK to save your settings.

i_round_blueIf you define channel limits when you also use the sensor's limit setting on the sensor's Settings tab, PRTG takes the first limit that applies. This way, you can individually define harder limits for single disks in a multi-disk sensor. All defined limits are valid.

You have to take the approach via channel settings for sensors that monitor only one (logical) disk, for example, the SNMP Disk Free sensor. For these sensors, you can use multi-edit if you want to automatically apply the same limits to each of these sensors.

Set Limits for Channels in Multi-Edit Mode

Set Limits for Channels in Multi-Edit Mode

  1. To see all SNMP Disk Free sensors, filter for the sensor type. Select Sensors | By Type | SNMP Disk Free from the main menu bar.
  2. Enable the check boxes next to the sensors for which you want to set a limit.
  3. Click b_multi_edit_settings.
  4. Select the Channel Settings tab.
  5. Select the channel to which you want to add a limit. In this case, select the channel Free Space.
  6. Enable the check box next to Limits.
  7. Select Enable alerting based on limits.
  8. Enter the desired Lower Warning Limit.
  9. Click OK to save your settings.

The new limit applies to all Free Space channels of all selected sensors.

Absolute Values and Delta Values for Limits

The value type that you need to configure for limits depends on the type of data that the channel delivers:

Value Type


Absolute values

For channels that measure absolute values, for example, for free disk space, you have to set limits with absolute values like 20.

Delta values

For channels that measure delta values, that is, measurements per second (x.xx/sec), you have to set delta values according to the formula number of errors/scanning interval in seconds.

For example, you have an SNMP Traffic sensor and want to receive an alert when the sensor reports errors:

  • Set the sensor to the Warning status when 1 error occurs.
  • Set the sensor to the Down status when 30 errors occur.

The following screenshot shows how to configure the limits for delta channels. You could set the following limits for the channel Errors in with a standard scanning interval of 60 seconds:

Setting Channel Limits with Delta Values

Setting Channel Limits with Delta Values

Because this channel uses per second (delta) measurements, the sensor reports a single error that occurs over a standard 60-second scanning interval as 0.016 # per second. So the warning limit for one single error within a scanning interval is 0.1 (errors/sec). To get an alert when there are 30 errors within a scanning interval, the limit needs to be 0.5 (errors/sec).

i_round_blueIf no new errors occur in the next scanning interval, the sensor shows the Up status again. To ensure that you do not miss any notifications for this sensor, set a notification trigger with 0 seconds.

Step 5: Set up the Notification Trigger

You specified limits to define when a sensor shows the Warning (or the Down) status. Now you can create suitable notification triggers. The notification trigger for this example is the state trigger.

i_square_cyanFor more information about available triggers, see section Notification Triggers Settings.

Set Notification Trigger for Disk Free Limit

Set Notification Trigger for Disk Free Limit

  1. Go to the sensor's Notification Triggers tab.
  2. Hover over b_add and select Add State Trigger from the menu.
  3. Set the notification trigger to When sensor state is Warning and select the notification template that you created before from the dropdown list.
  4. Adjust the other notification triggers settings to your needs.
  5. Click b_trigger_save to save the notification trigger.

Now you immediately receive a notification when the capacity of one of your disks falls below the defined limit, in this case 20% of free disk space.

Step 6: Test the Notification

Finally, test the notification that you created. You can immediately trigger a notification for test purposes:

  1. From the main menu bar, select Setup | Account Settings | Notification Templates.
  2. Click b_template_test next to the respective notification template to send a test notification.
  3. Check if the notification was correctly triggered and delivered based on the notification contacts and the notification method that you defined before. If you do not get a notification or if a defined action is not executed, check the notification logs. To do so, select Logs | System Events | Notification Related from the main menu bar. Look for the triggered notification in the table list and check that you correctly set up the notification delivery.

i_square_cyanFor more information, see section Logs.