<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: SNMP Trap Receiver Sensor

The SNMP Trap Receiver sensor receives and analyzes Simple Network Management Protocol (SNMP) traps.

i_round_blueThe sensor can also show the actual trap messages.

i_square_cyanFor a detailed list and descriptions of the channels that this sensor can show, see section Channel List.

SNMP Trap Receiver Sensor

SNMP Trap Receiver Sensor

Sensor in Other Languages

  • Dutch: SNMP Trap-ontvanger
  • French: Récepteur de traps 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

Remarks

  • 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 have 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.

i_podYou 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.

i_podTo import MIB files into PRTG Hosted Monitor, contact the Paessler support team.

Add Sensor

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. Therefore, you do not see all settings in this dialog. You can change nearly all settings on the sensor's Settings tab after creation.

Basic Sensor Settings

Click the Settings tab of a sensor to change its settings.

Basic Sensor Settings

Basic Sensor Settings

Setting

Description

Sensor Name

Enter a meaningful 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.

i_round_blueIf the name contains angle brackets (<>), PRTG replaces them with braces ({}) for security reasons. For more information, see the Knowledge Base: What security features does PRTG include?

Parent Tags

Shows tags that the sensor inherits from its parent device, parent group, and parent probe.

i_round_blueThis setting is for your information only. You cannot change it.

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.

i_round_blueIt is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>).

i_round_blueFor performance reasons, it can take some minutes until you can filter for new tags that you added.

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 (i_priority_1) to the highest priority (i_priority_5).

SNMP Trap Specific

SNMP Trap Specific

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 value.

i_round_blueWe recommend that you use the default value.

Purge Messages After

Define for how long PRTG stores received trap messages for analysis. Choose a period of time from the dropdown list.

Filter

i_square_cyanFor detailed information, see section Filter Rules.

Filter

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.

i_round_blueThe senor collects messages until a scanning interval ends. As long as the scanning interval is running, no status change happens. By default, the sensor changes to the Warning status after a scanning interval finishes and there was at least one warning message (and no error message) during this scanning interval. The sensor shows the Warning status at least until the succeeding scanning interval finishes. If the sensor does not receive any warning or error message in this scanning interval, its status changes to the Up status again with the start of the next scanning interval.

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.

i_round_blueThe senor collects messages until a scanning interval ends. As long as the scanning interval is running, no status change happens. By default, the sensor changes to the Down status after a scanning interval finishes and there was at least one error message during this scanning interval. The sensor shows the Down status at least until the succeeding scanning interval finishes. If the sensor does not receive any warning or error message in this scanning interval, its status changes to the Up status again with the start of the next scanning interval.

Sensor Display

Sensor Display

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.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary below a channel gauge on the sensor's Overview tab.

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.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

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.

Inherited Settings

By default, all of the following 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 b_inherited_enabled under the corresponding setting name to disable the inheritance and to display its options.

i_square_cyanFor more information, see section Inheritance of Settings.

Scanning Interval

Click b_inherited_enabled to interrupt the inheritance.

Scanning Interval

Scanning Interval

Setting

Description

Scanning Interval

Select a scanning interval from the dropdown list. The scanning interval determines the amount of time that the sensor waits between two scans. Choose from:

  • 30 seconds
  • 60 seconds
  • 5 minutes
  • 10 minutes
  • 15 minutes
  • 30 minutes
  • 1 hour
  • 4 hours
  • 6 hours
  • 12 hours
  • 24 hours

i_round_blueYou can change the available intervals in the system administration of PRTG Network Monitor.

If a Sensor Query Fails

Select the number of scanning intervals that the sensor has time to reach and to check a device again if a sensor query fails. Depending on the option that you select, the sensor can try to reach and to check a device again several times before the sensor shows the Down status. This can avoid false alarms if the monitored device only has temporary issues. For previous scanning intervals with failed requests, the sensor shows the Warning status. Choose from:

  • Set sensor to down immediately: Set the sensor to the Down status immediately after the first request fails.
  • Set sensor to warning for 1 interval, then set to down (recommended): Set the sensor to the Warning status after the first request fails. If the second request also fails, the sensor shows the Down status.
  • Set sensor to warning for 2 intervals, then set to down: Set the sensor to the Down status only after the third request fails.
  • Set sensor to warning for 3 intervals, then set to down: Set the sensor to the Down status only after the fourth request fails.
  • Set sensor to warning for 4 intervals, then set to down: Set the sensor to the Down status only after the fifth request fails.
  • Set sensor to warning for 5 intervals, then set to down: Set the sensor to the Down status only after the sixth request fails.

i_round_blueSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval before they show the Down status. It is not possible to immediately set a WMI sensor to the Down status, so the first option does not apply to these sensors. All other options can apply.

i_round_blueIf you define error limits for a sensor's channels, the sensor immediately shows the Down status. None of the interval options apply.

i_round_blueIf a channel uses lookup values, the sensor immediately shows the Down status. None of the interval options apply.

Schedules, Dependencies, and Maintenance Windows

i_round_blueYou 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 Windows

Schedules, Dependencies, and Maintenance Windows

Setting

Description

Schedule

Select a schedule from the list. You can use schedules to monitor during a certain time span (days or hours) every week. Choose from:

  • None
  • Saturdays
  • Sundays
  • Weekdays
  • Weekdays Eight-To-Eight (08:00 - 20:00)
  • Weekdays Nights (17:00 - 09:00)
  • Weekdays Nights (20:00 - 08:00)
  • Weekdays Nine-To-Five (09:00 - 17:00)
  • Weekends

i_round_blueYou can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Schedules.

Maintenance Window

Select if you want to set up a one-time maintenance window. During a maintenance window, monitoring stops for the selected object and all child objects. They show the Paused status instead. Choose between:

  • Do not set up a one-time maintenance window: Do not set up a one-time maintenance window. Monitoring is always active.
  • Set up a one-time maintenance window: Set up a one-time maintenance window and pause monitoring. You can define a time span for the pause below.

i_round_blueTo terminate an active maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

Maintenance Begins

This setting is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the one-time maintenance window.

Maintenance Ends

This setting is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the end date and time of the one-time maintenance window.

Dependency Type

Select a dependency type. You can use dependencies to pause monitoring for an object depending on the status of a different object. You can choose from:

  • Use parent: Use the dependency type of the parent object.
  • Select a sensor: Use the dependency type of the parent object. Additionally, pause the current object if a specific sensor is in the Down status or in the Paused status because of another dependency.
  • Master sensor for parent: Make this sensor the master object for its parent device. The sensor influences the behavior of its parent device: If the sensor is in the Down status, the device is paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor is paused if the parent group is paused by another dependency.

i_round_blueTo test your dependencies, select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects are paused. You can check all dependencies under Devices | Dependencies in the main menu bar.

Dependency

This setting is only visible if you enable Select a sensor above. Click b_search_light and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

This setting is only visible if you select Select a sensor above. Define a time span in seconds for the dependency delay.

After the master sensor for this dependency returns to the Up status, PRTG additionally delays the monitoring of the dependent objects by the time span you define. This can prevent false alarms, for example, after a server restart or to give systems more time for all services to start. Enter an integer value.

i_round_redThis setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, define delays in the parent device settings or in its parent group settings.

Access Rights

Click b_inherited_enabled to interrupt the inheritance.

Access Rights

Access Rights

Setting

Description

User Group Access

Define the user groups that have access to the sensor. You see a table with user groups and group access rights. The table contains all user groups in your setup. For each user group, you can choose from the following group access rights:

  • Inherited: Inherit the access rights settings of the parent object.
  • No access: Users in this user group cannot see or edit the sensor. The sensor neither shows up in lists nor in the device tree.
  • Read access: Users in this group can see the sensor and view its monitoring results. They cannot edit any settings.
  • Write access: Users in this group can see the sensor, view its monitoring results, and edit its settings. They cannot edit its access rights settings.
  • Full access: Users in this group can see the sensor, view its monitoring results, edit its settings, and edit its access rights settings.

i_square_cyanFor more details on access rights, see section Access Rights Management.

Channel Unit Configuration

Click b_inherited_enabled to interrupt the inheritance.

i_round_blueWhich 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

Channel Unit Configuration

Setting

Description

Channel Unit Types

For each type of channel, select the unit in which PRTG displays the data. If you define this setting on probe, group, or device level, you can inherit these settings to all sensors underneath. You can set units for the following channel types (if available):

  • Bandwidth
  • Memory
  • Disk
  • File
  • Custom

i_round_blueCustom channel types are only available on sensor level.

Debug Options

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.
    i_round_redUse with caution. We recommend that you only use this setting for a short time because it can create huge data files.

Filter Rules

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],
source[10.0.23.10/24]

agent[ip]

Enter an IP address that specifies the object that creates the SNMP trap.

i_round_redagent[ip] only supports v1.

agent[10.0.0.1]

enterprise[oid]

Enter an OID that specifies the object that originates the trap.

i_round_redenterprise[oid] only supports v1.

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[1.3.6.1.4.1.2.6.182.1.2.31.1.0],
bindings["port blocked"]

i_round_blueIt is not necessary to use quotation marks (") to find strings. If the string contains quotation marks that you want to include in the filter, you need to escape them with quotation marks.

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: This is the default mode that 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.
    i_round_redThis mode only supports integer values without extra characters and without thousands separators.
    i_round_blueIt also supports hex format.

bindings[1.3.6.1.4.1.2.6.182.1.2.31.1.0,error,exact]
bindings[1.3.6.1.4.1.2.6.182.1.2.31.1.0,10,equal]

gentrap[number]

Enter a number that specifies the generic trap type.

i_round_blueYou can also enter ranges.

gentrap[3], gentrap[2-6]

spectrap[number]

Enter a number that defines the specific trap code.

i_round_blueYou can also enter ranges.

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],
community[private]

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.

i_round_bluePRTG 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.

i_round_bluePRTG 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.

i_round_redThe parameters that you enter in the filters have to exactly match the parameters in the message. They are case sensitive.

i_round_blueYou can automatically add a filter by clicking the content of a column.

Advanced Filter Settings

You can open advanced filter settings by clicking b_filter_advanced 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.

Channel List

i_round_blueWhich channels the sensor actually shows might depend on the monitored 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 in percent.

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

i_round_blueThis channel is the primary channel by default.

Warnings

The number of messages categorized as "warning" per second

More

i_square_blueKNOWLEDGE BASE

What placeholders can I use with PRTG?

How can I configure sensors using speed limits to keep the status for more than one interval?

How can I show the name of a received OID in PRTG?

How do I test an SNMP Trap Receiver sensor?

What security features does PRTG include?

What SNMP sensors does PRTG offer?

My SNMP sensors don’t work. What can I do?

Sensor Settings Overview

For more information about sensor settings, see the following sections: