PRTG Manual: SNMP Trap Receiver Sensor
The SNMP Trap Receiver sensor receives and analyzes Simple Network Management Protocol (SNMP) traps. It returns the number of new traps per second received within the last scanning interval as well as the number of warnings per second.
For a general introduction to the technology behind SNMP, please see Monitoring via SNMP section.
The Add Sensor dialog appears when adding a new sensor on a device manually. It only shows the setting fields that are imperative for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change all settings in the sensor's Settings tab later.
On the sensor's details page, click on the Settings tab to change settings.
Note: If not set explicitly in a sensor's settings, it will connect to the IP Address or DNS Name defined in the settings of the parent device the sensor is created on.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful name to identify the sensor. The name will be shown by default in the device tree and in all alarms. |
Tags |
Enter one or more tags, separated by space or comma. You can use tags to group sensors and use tag-filtered views later on. Tags are not case sensitive. We recommend using the default value. You can add additional tags to it, if you like. Other tags are automatically inherited from objects further up in the device tree. Those are not visible here. |
Priority |
Select a priority for the sensor. This setting determines where the sensor will be placed in sensor lists. Top priority will be at the top of a list. You can choose from one star (low priority) to five stars (top priority). |
OID Values |
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OID Value |
Enter the OID of the SNMP object you want to receive numerical data from. |
Listen on Port |
Define the port on which SNMP traps are received. We recommend using the default value. |
When Message Comes In |
Define what will be done when a message comes in. Choose between:
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Sender |
Define if you want to filter for a specific sender only. If you enter something here, only traps with this sender will be regarded. Make sure the string matches exactly the value of the sender value in the trap. Please enter a string or leave the field empty. |
Specific Trap Code |
Define if you want to filter for a specific trap code value only. If you enter something here, only traps with this code will be regarded. Make sure the value matches exactly the code in the trap. Please enter an integer value or leave the field empty. |
Set Sensor to 'Warning' |
Define when the sensor will be put to a Warning status. Choose between:
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Message Must Include |
This setting is only visible if a sensor status change is enabled above. Define which string must be part of the trap's message. If the message does not include this string, the sensor will be set to a Warning status. Please enter a string or leave the field empty. |
Message Must Not Include |
This setting is only visible if a sensor status change is enabled above. Define which string must not be part of the trap's message. If the message does include this string, the sensor will be set to a Warning status. Please enter a string or leave the field empty. |
Sensor Display |
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Primary Channel |
Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed underneath the sensor's name. The available options depend on what channels are available for this sensor. |
Chart Type |
Define how different channels will be shown for this sensor.
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Stack Unit |
This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked 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. |
By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings. To change a setting for this object, disable inheritance by clicking on the check mark symbol in front of the respective setting name. You will then see the options described below.
Scanning Interval |
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Scanning Interval |
The scanning interval determines the time the sensor waits between two scans. Select a scanning interval (seconds, minutes, or hours) from the list. You can change the available intervals in the system administration. |
Schedules, Dependencies, and Maintenance Window |
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Note: Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted; the according settings from the parent objects will always be active. However, you can define additional settings here. They will be active in parallel to the parent objects' settings. |
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Schedule |
Select a schedule from the list. Schedules can be used to pause monitoring for a certain time span (days, hours) throughout the week. You can create new schedules and edit existing ones in the account settings. Note: Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active. |
Maintenance Window |
Specify if you want to set-up a one-time maintenance window. During a maintenance window this object and all child objects will not be monitored. They will enter a paused state then. Choose between:
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Maintenance Begins At |
This field is only visible if maintenance window is enabled above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance End At |
This field is only visible if maintenance window is enabled above. Use the date time picker to enter the end date and time of the maintenance window. |
Dependency Type |
Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:
Note: Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. |
Dependency |
This field is only visible if the select object option is enabled above. Click on the reading-glass symbol and use the object selector to choose an object on which the current sensor will be dependent on. |
Delay (Seconds) |
Define a time span. After the master object for this dependency comes back to an Up status, monitoring of the depending objects will be additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value in seconds. Note: This setting is not available if you choose this sensor to be the Master object for parent. In this case, please define delays in the parent Device Settings or the superior Group Settings. |
Access Rights |
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User Group Access |
Define which user group(s) will have access to the object you're editing. A table with user groups and right is shown; it contains all user groups from your setup. For each user group you can choose from the following access rights:
You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option. |
Knowledge Base: How can I use PRTG’s trap receiver and what are its limitations?
Knowledge Base: How do I find out what OID I need to use for a custom sensor?
Knowledge Base: How do I test an SNMP Trap Receiver Sensor?
Click on the Channels tab to change display settings, spike filter, and limits. For detailed information, please see Sensor Channels Settings section.
Click on the Notifications tab to change notification triggers. For detailed information, please see Sensor Notifications Settings section.
For more general information about settings, please see Object Settings section.
For information about sensor settings, please see the following sections:
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