PRTG Manual: SNMP Traffic Sensor

The SNMP Traffic sensor monitors traffic on a device via the Simple Network Management Protocol (SNMP).

i_round_blueYou can create the sensor on a device that provides traffic data.

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

SNMP Traffic Sensor

SNMP Traffic Sensor

Sensor in Other Languages

  • Dutch: SNMP Verkeer
  • French: Trafic SNMP
  • German: SNMP Datenverkehr
  • Japanese: SNMP トラフィック
  • Portuguese: Tráfego SNMP
  • Russian: Трафик по SNMP
  • Simplified Chinese: SNMP 流量
  • Spanish: SNMP tráfico

Remarks

  • You can define the displayed sensor name with port name templates in the SNMP compatibility options of the parent device.
  • We recommend that you select SNMP v2c (most common) or SNMP v3 in the credentials for SNMP devices of the parent device (if supported by the device that you monitor). SNMP v1 does not support 64-bit counters, which may result in invalid data. For details, see the Knowledge Base: SNMP Traffic sensor suddenly drops at 610Mbps
  • It might not work to query data from a probe device via SNMP (querying localhost, 127.0.0.1, or ::1). Add this device to PRTG with the IP address that it has in your network and create the SNMP sensor on this device instead.
  • This sensor supports the IPv6 protocol.
  • This sensor has a very low performance impact.

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.

Traffic Specific

Setting

Description

Interface Number

Select the ports on SNMP devices with multiple interfaces that you want to monitor. PRTG creates one sensor for each port that you select.

i_round_blueEnable check boxes in front of the respective lines to select the items. Use the check box in the table header to select all items or to cancel the selection. In large tables, use the search function in the upper-right corner.

i_round_blueYou can see the connection status of an interface in the respective table column.

i_round_blueYou can select interfaces and cancel the selection by clicking Select all connected interfaces, Select all disconnected interfaces, and Deselect all interfaces.

Name for Traffic In Channel

For the standard channel Traffic In, enter the channel name here. The sensor shows it in graphs and tables. You can change this description and the description of all other channels in the channel settings later.

Name for Traffic Out Channel

For the standard channel Traffic Out, enter the channel name here. The sensor shows it in graphs and tables. You can change this description and the description of all other channels in the channel settings later.

Name for Traffic Total Channel

For the standard channel Traffic Total, enter the channel name here. The sensor shows it in graphs and tables. You can change this description and the description of all other channels in the channel settings later.

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:

  • bandwidthsensor
  • snmptrafficsensor

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).

i_round_blueUsually, a sensor connects to the IP Address/DNS Name of the parent device. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings.

Traffic Specific

Traffic Specific

Traffic Specific

Setting

Description

Interface Number

Shows the number and name of the interface in the physical device that this sensor monitors.

i_round_redPRTG shows this value for reference purposes only. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.

Additional Channels

By default, each SNMP Traffic sensor creates the channels Traffic In, Traffic Out, and Traffic Total. Select additional channels for all interfaces. Click the respective channel names to mark the channels and to monitor their data.

You can choose between the following additional channels:

  • Errors in and Errors out: The number of incoming and outgoing packets that could not be delivered because of errors.
  • Discards in and Discards out: The number of discarded incoming and outgoing packets even though no errors have been detected.
  • Unicast packets in Unicast packets out: The number of unicast packets that have been delivered.
  • Non Unicast packets in and Non Unicast packets out (32-bit only): The number of non-unicast packets that have been delivered.
  • Multicast packets in and Multicast packets out (64-bit only): The number of delivered packets that were addressed to a multicast address.
  • Broadcast packets in and Broadcast packets out (64-bit only): The number of delivered packets that were addressed to a broadcast address
  • Unknown Protocols: The number of received packets that were discarded because of an unknown or unsupported protocol.

i_round_redYou cannot delete additional channels later. You can only disable them.

i_round_blueIf the sensor shows the Warning status with the message Channels not available, you can disable the affected channels to remove the warning.

Connection Status Handling

Define how PRTG reacts when an interface is operational. An interface that is not operational is, for example, an Ethernet port on a switch with no cable plugged in. This setting is valid for all selected interfaces. Choose between:

  • Show down status for all disconnected states: Show the Down status for a disconnected interface. This applies if the ifOperStatus of the interface is not "up".
  • Show down status when disconnected, ignore when deactivated: Show the Down status for a disconnected interface only if it is not deliberately deactivated in the configuration. This applies if the ifOperStatus of the interface is not "up" and the ifAdminStatus is "up". So the sensor stays in the Up status when the interface has been deactivated.
  • Ignore all disconnected states: Show the Up status.
    i_round_blueMonitoring is discontinued without notice.

Alias Availability

Shows if an alias is available for automatic port name updates.

i_round_redPRTG shows this value for reference purposes only. We strongly recommend that you only change it if the Paessler support team explicitly asks you to do so. Wrong usage can result in incorrect monitoring data.

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).
  • Show in and out traffic as positive and negative area graph: Show channels for incoming and outgoing traffic as positive and negative area graph. This visualizes your traffic in a clear way.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings). Manual scaling is not possible if you choose this option.
    i_round_redYou cannot show a positive/negative graph for a channel if you choose to display its data in percent of maximum (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.

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.

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

Discards In

The number of incoming discards per second

Discards Out

The number of outgoing discards per second

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.

Errors In

The number of incoming errors per second

Errors Out

The number of outgoing errors per second

Non-Unicast In

The number of incoming non-unicast packets per second

Non-Unicast Out

The number of outgoing non-unicast packets per second

Traffic In

The incoming traffic in bytes per second

Traffic Out

The outgoing traffic in bytes per second

Traffic Total

The total traffic in bytes per second

i_round_blueThis channel is the primary channel by default.

Unicast In

The number of incoming unicast packets per second

Unit

The number of outgoing unicast packets per second

Unknown Protocols In

The number of incoming, unknown protocols per second

More

i_square_blueKNOWLEDGE BASE

How does auto-discovery with SNMP Traffic sensors work?

SNMP Traffic sensors when the device changes them

Where is the volume line in graphs?

What security features does PRTG include?

SNMP Traffic sensor suddenly drops at 610Mbps

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: