PRTG Manual: SNMP Trap Receiver Sensor
The SNMP Trap Receiver sensor receives and analyzes Simple Network Management Protocol (SNMP) traps.
The sensor can also show the actual trap messages.
SNMP Trap Receiver Sensor
For a detailed list and descriptions of the channels that this sensor can show, see section Channel List.
▪Dutch: SNMP Trap-ontvanger
▪French: Récepteur de Trap (SNMP)
▪German: SNMP-Trap-Empfänger
▪Japanese: SNMP トラップレシーバー
▪Portuguese: Receptor de trap SNMP
▪Russian: Приемник ловушек SNMP
▪Simplified Chinese: SNMP 陷阱接收程序
▪Spanish: Receptor de trap SNMP
▪This sensor has a very high performance impact. Use it with care. We recommend that you use no more than 50 sensors of this sensor type on each probe.
▪This sensor does not support SNMP v3 traps. Use SNMP v1 or v2c instead.
▪This sensor only supports the User Datagram Protocol (UDP).
▪Add this sensor to the probe device to receive all messages of the remote probe system.
▪Add this sensor to a specific device to directly receive all messages from this device. This makes this sensor faster than when you use source filters.
▪This sensor supports the IPv6 protocol.
▪You can use specific placeholders in email notification templates to see the messages when you receive an email notification. See section List of Placeholders for Notifications.
▪The sensor states of this sensor persist for one scanning interval only. After showing a Warning status or a Down status, and if there is no warning or error message in the following scanning interval, the sensor shows an Up status again. For a workaround, see the Knowledge Base: How can I configure sensors using speed limits to keep the status for more than one interval?
▪With the available filter options, you can individually define which types of messages the sensor considers for monitoring, and which messages it categorizes as warning or error messages. Depending on the filters, received messages are counted in the respective channels.
▪If you do not add the sensor to a probe device but to a different device in PRTG, be careful with the configuration: Ensure that the IP address or Domain Name System (DNS) name of the parent device matches the proper sender. For example, if you want to receive messages from a storage area network (SAN), you might need to add a device to PRTG using the IP address of a specific array member that sends the messages. Providing a DNS name that points to the IP address of a whole group might not work for SANs.
▪In PRTG Network Monitor, you can copy the Management Information Base (MIB) file for your traps into the \MIB subfolder of the PRTG program directory to translate the object identifiers (OID) for the traps into readable messages. For details, see the Knowledge Base: How can I show the name of a received OID in PRTG?
▪You cannot use this sensor in cluster mode. You can only set it up on a local probe or a remote probe but not on a cluster probe.
▪See the Knowledge Base: How do I test an SNMP Trap Receiver sensor?
▪For a general introduction to the receiver's configuration, see section Monitoring Syslogs and SNMP Traps.
You cannot add this sensor to the hosted probe of a PRTG Hosted Monitor instance. If you want to use this sensor, add it to a remote probe device.
To import MIB files into PRTG Hosted Monitor, see section Manage a PRTG Hosted Monitor Subscription.
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the settings that are required to create the sensor. You can change nearly all settings on the sensor's Settings tab after creation.
Click the Settings tab of a sensor to change its settings.
Basic Sensor Settings
Setting |
Description |
|---|---|
Sensor Name |
Enter a name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.
|
Parent Tags |
Shows tags that the sensor inherits from its parent device, parent group, and parent probe.
|
Tags |
Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited.
The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor: ▪snmptrapsensor |
Priority |
Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority ( |
SNMP Trap Specific
Setting |
Description |
|---|---|
Port |
Enter the number of the port on which the sensor listens for SNMP traps. The default port is 162. Enter an integer.
|
Purge Messages After |
Define for how long PRTG stores received trap messages for analysis. Choose a period of time from the dropdown list. |
For detailed information, see section Filter Rules.
Filter
Setting |
Description |
|---|---|
Include Filter |
Define if you want to filter traps. If you leave this field empty or use the keyword any, the sensor processes all data. To include only specific types of traps, define filters using a special syntax. |
Exclude Filter |
Define which types of traps the sensor discards and does not process. To exclude specific types of traps, define filters using a special syntax. |
Warning Filter |
Define which types of traps count for the Warnings channel. To categorize received traps as warning messages, define filters using a special syntax.
|
Error Filter |
Define which types of traps count for the Errors channel. To categorize received traps as error messages, define filters using a special syntax.
|
Sensor Display
Setting |
Description |
|---|---|
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 is always displayed below the sensor's name. The available options depend on what channels are available for this sensor.
|
Graph Type |
Define how different channels are shown for this sensor: ▪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. |
Stack Unit |
This setting is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are 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 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 
under the corresponding setting name to disable the inheritance and to display its options.
For more information, see section Inheritance of Settings.
Scanning Interval
For more information, see section Root Group Settings, section Scanning Interval.
Schedules, Dependencies, and Maintenance Window
You cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.
Schedules, Dependencies, and Maintenance Window
For more information, see section Root Group Settings, section Schedules, Dependencies, and Maintenance Window.
Access Rights
For more information, see section Root Group Settings, section Access Rights.
Which channel units are available depends on the sensor type and the available parameters. If no configurable channels are available, this field shows No configurable channels.
Channel Unit Configuration
For more information, see section Root Group Settings, section Channel Unit Configuration.
Debug Options
Debug Options
Setting |
Description |
|---|---|
Result Handling |
Define what PRTG does with the sensor result: ▪Discard result (recommended): Do not store the sensor result. ▪Store result: Store the last sensor result in the \Logs\debug subfolder of the PRTG data directory on the probe system. The file name is Sensor [ID]_[Date].log. This setting is for debugging purposes. |
Filter rules are used for the include, exclude, warning, and error definition fields of the SNMP Trap Receiver sensor. They are based on the following format:
field[filter]
You can use include and exclude filters to define which traps to monitor or use warning and error filters to define how to categorize received traps. Provide these filters in the sensor settings as formulas. Formulas are fields that you can combine with boolean operators (AND, OR, NOT) and brackets.
Field |
Parameter |
Examples |
|---|---|---|
source[ip] |
Enter an IP address where the UDPs come from. IP masks and ranges are also possible. |
source[10.0.23.50], source[10.0.23.10-50], |
agent[ip] |
Enter an IP address that specifies the object that creates the SNMP trap.
|
agent[10.0.0.1] |
enterprise[oid] |
Enter an OID that specifies the object that originates the trap.
|
enterprise[1.3.6.1.4.1.2.6.182.1.2.31.1.0] |
bindings[text] |
Enter a substring to match all OIDs and values in the bindings. |
bindings[ERROR],
|
bindings[oid,value] |
Enter an OID and a substring to match a value in the specified OID. Separate the OID and the value with a comma. |
bindings[1.3.6.1.4.1.2.6.182.1.2.31.1.0,error] |
bindings[oid,value,mode] |
Enter an OID, a substring, and a mode to match a value in the specified OID. Separate the OID, the value, and the mode with a comma. The mode can be: ▪substring (default): This mode works like bindings[oid,value]. ▪exact: This mode enforces an exact match of a value. ▪equal, greater, greaterorequal, less, or lessorequal: This interprets and compares values as numbers. |
bindings[1.3.6.1.4.1.2.6.182.1.2.31.1.0,error,exact] |
gentrap[number] |
Enter a number that specifies the generic trap type.
|
gentrap[3], gentrap[2-6] |
spectrap[number] |
Enter a number that defines the specific trap code.
|
spectrap[4], spectrap[0-3] |
version[number] |
Enter a number (1 or 2) that specifies the SNMP version. |
version[1], version[2] |
community[text] |
Enter a community string for an exact, case-sensitive match. |
community[public], |
Messages Tab: Review and Analyze Traps
PRTG stores received traps as common files in the \Trap Database subfolder of the PRTG data directory. To review and analyze all received messages, you can directly access the most recent data in a table list in the PRTG web interface. You can access this list via the sensor's Overview tab.
PRTG only shows received traps in the table on the Overview tab after an (automatic) page refresh following a sensor scan. The default value for auto refresh is 30 seconds.
For more details and further filter options, click the Messages tab of the SNMP Trap Receiver sensor. You see all received messages in a table list. At the top, you have display filter options to drill down into the data for specific events of your interest. The filters are the same as those that are available in the sensor settings, but you can define them without using formulas. Provide the desired parameters and PRTG automatically loads the filtered list.
PRTG automatically applies boolean operators to the filters in the following manner: parameters across all columns are combined with AND, and parameters within a single column are combined with OR.
The parameters that you enter in the filters must exactly match the parameters in the message. They are case sensitive.
You can automatically add a filter by clicking the content of a column.
Advanced Filter Settings
You can open advanced filter settings by clicking 
in the Filter row. The Advanced Filter appears in a popup window. In the text field, you can define a filter using the syntax as described in section Filter Rules.
If you provided filter parameters on the Messages tab, the advanced filter already includes them as a corresponding formula with the correct syntax. You can adjust this filter to your needs. You can also copy the automatically created and manually adjusted formula for usage in the filter fields of the sensor settings.
Which channels the sensor actually shows might depend on the target device, the available components, and the sensor setup.
Channel |
Description |
|---|---|
Downtime |
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 |
Drops |
The number of dropped packets per second on the SNMP trap collector port |
Errors |
The number of messages categorized as "error" per second |
Messages |
The overall number of received traps per second
|
Warnings |
The number of messages categorized as "warning" per second |
KNOWLEDGE BASE
How can I configure sensors using speed limits to keep the status for more than one interval?
▪https://kb.paessler.com/en/topic/73212
How can I show the name of a received OID in PRTG?
▪https://kb.paessler.com/en/topic/63562
How do I test an SNMP Trap Receiver sensor?
▪https://kb.paessler.com/en/topic/10193
What security features does PRTG include?
▪https://kb.paessler.com/en/topic/61108
My SNMP sensors don’t work. What can I do?
