<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: NetFlow v5 (Custom) Sensor

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.

If 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.

This 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.

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

For 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
• netflowsensor

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 () to the highest priority ().

Receive NetFlow Packets on UDP Port

Enter the User Datagram Protocol (UDP) port number on which the flow packets are received. It must match the UDP port number in the NetFlow export options of the hardware router device. Enter an integer value.

When you configure the export, make sure that you select the appropriate NetFlow version for this sensor.

Sender IP

Enter the IP address of the sending device that you want to receive the NetFlow from. Enter an IP address to only receive data from a specific device or leave the field empty to receive data from any device on the specified port.

Receive NetFlow Packets on IP

Select the IP addresses on which PRTG listens to NetFlow packets. The list of IP addresses is specific to your setup. To select an IP address, add a check mark in front of the respective line. The IP address that you select must match the IP address in the NetFlow export options of the hardware router device.

When you configure the export, make sure that you select the appropriate NetFlow version for this sensor.

You can also select all items or cancel the selection by using the check box in the table header.

Active Flow Timeout (Minutes)

Enter a time span in minutes after which the sensor must receive new flow data. If the timeout elapses and the sensor receives no new data during this time, it shows the Unknown status. Enter an integer value. The maximum timeout is 60 minutes.

We recommend that you set the timeout one minute longer than the timeout in the hardware router device.

If you set this value too low, flow information might be lost.

For more details, see the Knowledge Base: What is the Active Flow Timeout in Flow sensors?

If the target device sends incorrect time information that results in wrong monitoring data, try to use 0 as active flow timeout. This ignores the start and stop information of a flow as provided by the device and accounts all data to the current point in time. It might result in spikes but all data is captured.

Sampling Mode

Define if you want to use the sampling mode:

• Off: Use the standard flow.
• On: Use the sampling mode and specify the Sampling Rate below.

This setting must match the setting in the xFlow exporter.

Sampling Rate

This setting is only visible when sampling mode is On above. Enter a number that matches the sampling rate in your device that exports the xFlows. If the number is different, monitoring results will be incorrect. Enter an integer value.

Channel Definition

Enter a channel definition to divide the traffic into different channels. Enter each definition in one line. The sensor accounts all traffic that you do not define a channel for to the default channel Other.

For detailed information, see section Channel Definitions for xFlow, IPFIX, and Packet Sniffer Sensors.

Extensive use of many filters can cause load problems on the probe system. We recommend that you define specific, well-chosen filters for the data that you really want to analyze. We recommend that you do not use more than 20 channels in graphs and tables, and not more than 100 channels in total. For performance reasons, we recommend that you add several sensors with fewer channels each.

Stream Data Handling

Define what PRTG does with the stream and packet data:

• Discard stream data (recommended): Do not store the stream and packet data.
• Store stream data only for the 'Other' channel: Only store stream and packet data that is not otherwise filtered and is therefore accounted to the default Other channel. PRTG stores this data in the \StreamLog subfolder of the PRTG data directory on the probe system. The file name is Streams Sensor [ID] (1).csv. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval.
• Store all stream data: Store all stream and packet data. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval.

Use with caution. If you enable this setting, it can create huge data files. We recommend that you only use this setting for a short time.

Include Filter

Define if you want to filter any traffic. If you leave this field empty, the sensor includes all traffic. To include specific traffic only, define filters using a special syntax.

Exclude Filter

First, the sensor considers the filters in Include Filter. From this subset, you can explicitly exclude traffic, using the same syntax.

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.

You can set a different primary channel later by clicking 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.
  You 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.

Primary Toplist

Define which Toplist is the primary Toplist of the sensor:

• Top Talkers
• Top Connections
• Top Protocols
• [Any custom Toplists you add]

PRTG shows the primary Toplist in maps when you add a Toplist object.

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

You can change the available intervals in the system administration on PRTG on premises installations.

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.

Sensors 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.

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

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

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

You 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.

To 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.

To 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 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 enable 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.

This 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.

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.

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

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

Custom channel types are only available on sensor level.

IP

IP address or Domain Name System (DNS) name

Port

Any number

SourceIP

IP address or Domain Name System (DNS) name

SourcePort

Any number

DestinationIP

IP address or Domain Name System (DNS) name

DestinationPort

Any number

Protocol

Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Internet Control Message Protocol (ICMP), Open Shortest Path First (OSPF), any number

ToS

Type of Service (ToS): any number

DSCP

Differentiated Services Code Point (DSCP): any number

Interface

Any number

ASI

Any number

InboundInterface

Any number

OutboundInterface

Any number

SenderIP

IP of the sending device. Use this if you have several devices that send flow data on the same port, and you want to divide the traffic of each device into a different channel.

Possible values: IP address or DNS name

SourceASI

Any number

DestinationASI

Any number

[Custom]

The traffic by type according to the channel definition

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.

Other

All traffic for which no channel is defined in bytes per second

Total

The total traffic in bytes per second

This channel is the primary channel by default.