PRTG keeps you or other responsible people informed about the status of the network. There are several methods that you can use to stay up to date.
Internal Sensor Alerts
Alerts are an important part of monitoring that informs you when there are issues, when values exceed limits, or when a sensor status changes, for example. Some sensors display internal alerts in case of errors, for example, disconnected probes or socket and timeout errors. There are also sensors whose internal sensor alerts you can modify. To see if you can modify an alert, check the sensor's settings for customizable options.
Here is an example of a sensor that is in the Down status because of an internal sensor alert.
Probe Health Sensor with Disconnected Probe Alert
HTTP sensors, for example, show preconfigured internal alerts based on specific HTTP status codes.
For more information, see the Knowledge Base: Which HTTP status code leads to which HTTP sensor status?
There are also alerts that are triggered by limits that you can set in the channel settings of a sensor. PRTG triggers a sensor status change when a sensor measures values that exceed or fall below a defined limit. For example, you can set an SNMP CPU Load sensor to the Down status when it measures values that you consider critical. This sensor then appears in the alarms list as well.
This type of alert only applies when a value breaches the configured limits. If the value is normal again in the next sensor scan, the sensor shows the Up status again.
The value type that you need to configure for limits depends on the type of data that the channel returns. You can set absolute values or delta values .
For more information, see the video tutorial: How to set channel limits .
Lookups for Channels
PRTG also uses lookups for some sensors. In general, lookups make data more human friendly because they map status values that a device returns, usually integers, to more informative expressions in words that show you the status of a target device in plain text.
SNMP HP LaserJet Hardware Gauge
Additionally, lookups can define the sensor status in combination with specific status codes. For example, a sensor can show the Unknown status if a channel value, provided by lookups, indicates that the device is Inactive , instead of displaying a numeric value like -1 .
You can also modify preconfigured lookups or create your own custom lookups.
For more information, see section Define Lookups .
PRTG can send a notification when it discovers, for example, downtime, an overloaded system, threshold breaches, or similar situations. Notifications use various methods to notify you of issues. After you create notification templates in the system settings, you can select the templates on the Notification Triggers tab of probes, groups, devices, and sensors, as well as the root group.
The status or the data of a sensor can also trigger notifications. With this mechanism, you can configure custom external alerts. Which notification triggers are available depends on the kind of object you edit. You can define notification triggers that are activated by an 'on change' event. Some sensors offer the option to trigger a notification whenever sensor values change.
For more information, see section Notifications .
The alarms list shows all sensors that are in the Down , Down (Partial) , Down (Acknowledged) , Warning , or Unusual status. Sensors in the Up , Paused , or Unknown states do not appear here.
For more information, see section Alarms .
The logs list shows the log file that includes all monitoring events. PRTG documents the activity of every single object, so you can use this data to check if your setup works as expected.
For more information, see section Logs .
The tickets list shows tickets with important system information or actions that you need to take. We recommend that you view every ticket and take appropriate action. By default, PRTG sends an email to the PRTG System Administrator user for every new ticket that the system or a user creates. If a ticket is assigned to a specific user, this user also receives an email by default.
For more information, see section Tickets .
Which HTTP status code leads to which HTTP sensor status?
How to set channel limits
