<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: NetFlow V9 (Custom) Sensor

The NetFlow V9 (Custom) sensor receives traffic data from a NetFlow V9 compatible device and shows the traffic by type. Please make sure the sensor matches the NetFlow version your device is exporting! In this custom sensor, you can define your own channel definitions to divide traffic into different channels.

  • This sensor can show traffic by type individually according to your needs.

Which channels the sensor actually shows might depend on the monitored device and the sensor setup.

NetFlow V9 Sensor

NetFlow V9 Sensor

Click here to enlarge: http://media.paessler.com/prtg-screenshots/netflow_v9.png

Remarks

  • You must enable NetFlow export of the respective version on the monitored device for this sensor to work. The device must send the flow data stream to the IP address of the PRTG probe system on which the sensor is set up (either a local or remote probe).
  • This sensor type cannot be used in cluster mode. You can set it up on a local probe or remote probe only, not on a cluster probe.
  • Knowledge Base: What is the Active Flow Timeout in Flow sensors?
  • This sensor does not support more than 50 channels officially.
  • For a general introduction to the technology behind flow monitoring, please see manual section Monitoring Bandwidth via Flows.

icon-prtg-on-demandYou cannot add this sensor type to cloud probes in PRTG in the cloud. If you want to use this sensor type, please add it to a remote probe device.

Limited to 50 Sensor Channels

icon-i-bluePRTG does not support more than 50 sensor channels officially. Depending on the data used with this sensor type, you might exceed the maximum number of supported sensor channels. In this case, PRTG will try to display all sensor channels. However, please be aware that you will experience limited usability and performance.

Add Sensor

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

icon-i-roundUsually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details on available settings.

Basic Sensor Settings

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.

Parent Tags

Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

NetFlow Specific Settings

Receive NetFlow Packets on UDP Port

Enter the UDP port number on which the flow packets are received. It must match the one you have configured in the NetFlow export options of your hardware router device. Please enter an integer value.

icon-i-roundWhen configuring export, make sure you select the appropriate NetFlow version for this sensor.

Sender IP

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

Receive NetFlow Packets on IP

Select the IP address(es) on which PRTG listens to NetFlow packets. The list of IP addresses you see here is specific to your setup. To select an IP address, add a check mark in front of the respective line. You can also select and deselect all items by using the check box in the table head. The IP address you select here must match the one you have configured in the NetFlow export options of your hardware router device.

icon-i-roundWhen configuring export, please make sure you select the appropriate NetFlow version for this sensor.

Active Flow Timeout (Minutes)

Enter a time span in minutes after which new flow data must be received. If the timeout is reached and no new data was received during this time, the sensor switches to an Unknown status. Please enter an integer value.

We recommend that you set the timeout one minute longer than the respective timeout configured in your hardware router device. The maximum timeout is 60 minutes.

icon-i-redIf you set this value too low, flow information might be lost!
 

icon-book-bulbFor more details, please see this Knowledge Base article: What is the Active Flow Timeout in Flow sensors?
 

icon-i-roundIf the target device sends incorrect time information that results in wrong monitoring data, please try to use 0 as active flow timeout. This will ignore the start and stop information of a flow as provided by the device and account all data to the current point in time. It might result in spikes but all data will be captured.

Sampling Mode

Define if you want to use the sampling mode. This setting must accord to the setting in the flow exporter. Choose between:

  • Off: The standard flow will be used.
  • On: Switch into sampling mode and specify the sampling rate below.

Sampling Rate

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

Channel Definition

Please enter a channel definition to divide the traffic into different channels. Write each definition in one line. For detailed information, please see Channel Definitions for xFlow, IPFIX, and Packet Sniffer Sensors section. All traffic for which no channel is defined will be accounted to the default channel named Other.

Extensive use of many filters can cause load problems on your probe system. We recommend defining specific, well-chosen filters for the data you really want to analyze.

Log Stream Data to Disk (for Debugging)

Define if you want the probe to write a logfile of the stream and packet data to the data folder (see Data Storage). Choose between:

  • None (recommended): Do not write additional logfiles. Recommended for normal use cases.
  • Only for the 'Other' channel: Only write logfiles of data that is not filtered otherwise and therefore accounted to the default Other channel.
  • All stream data: Write logfiles for all data received.

icon-i-redUse with caution! When enabled, huge data files can be created. Please use for a short time and for debugging purposes only.

Filtering

Include Filter

Define if you want to filter any traffic. If you leave this field empty, all traffic will be included. To include specific traffic only, define filters using a special syntax. For detailed information, please see Filter Rules below.

Exclude Filter

First, the filters defined in the Include Filter field are considered. From this subset, you can explicitly exclude traffic, using the same syntax. For detailed information, please see Filter Rules below.

Sensor Display

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 below the sensor's name. The available options depend on what channels are available for this sensor.

icon-i-roundYou can set another primary channel later by clicking the pin symbol of a channel in the sensor's Overview tab.

Graph Type

Define how different channels will be shown for this sensor.

  • Show channels independently (default): Show an own 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 will generate an easy-to-read graph that visualizes the different components of your total traffic.
    icon-i-roundThis option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).

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.

Primary Toplist

Primary Toplist

Define which will be your primary toplist. It will be shown in maps when adding a toplist object. Choose from:

  • Top Talkers
  • Top Connections
  • Top Protocols
  • [Any custom toplists you have added]

Inherited Settings

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 only for this object, disable inheritance by clicking the check mark in front of the corresponding setting name. You will then see the options described below.

Scanning Interval

Scanning Interval

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Define the number of scanning intervals that a sensor has time reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:

  • Set sensor to "down" immediately: The sensor will show an error immediately after the first failed request.
  • Set sensor to "warning" for 1 interval, then set to "down" (recommended): After the first failed request, the sensor will show a yellow warning status. If the following request also fails, the sensor will show an error.
  • Set sensor to "warning" for 2 intervals, then set to "down": Show an error status only after three continuously failed requests.
  • Set sensor to "warning" for 3 intervals, then set to "down": Show an error status only after four continuously failed requests.
  • Set sensor to "warning" for 4 intervals, then set to "down": Show an error status only after five continuously failed requests.
  • Set sensor to "warning" for 5 intervals, then set to "down": Show an error status only after six continuously failed requests.

icon-i-roundSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to "down" immediately, so the first option will not apply to these sensor types. All other options can apply.

icon-i-roundIf a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.
 

icon-i-roundIf a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Schedules, Dependencies, and Maintenance Window

icon-i-roundInheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

icon-i-roundSchedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a paused state instead. Choose between:

  • Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.
  • Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

icon-i-roundTo terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends field to a date in the past.

Maintenance Begins

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enabled the maintenance window 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:

  • Use parent: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency.
  • Select object: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in Down status, or is paused by another dependency. Select below.
  • Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device, where it is created on: If the sensor is in Down status, the device will be 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 will be paused if the parent group of its parent device is in Down status, or if it is paused by another dependency.

icon-i-roundTesting 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. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend.

Dependency Delay (Sec.)

Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to 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.

icon-i-round-redThis setting is not available if you choose this sensor to Use parent or to be the Master object for parent. In this case, please define delays in the parent Device Settings or in the superior Group Settings.

Access Rights

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown: It contains all user groups from your setup. For each user group you can choose from the following access rights:

  • Inherited: Use the access rights settings of the parent object.
  • None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
  • Read: Users in this group can see the object and review its monitoring results.
  • Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
  • Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

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.

For more details on access rights, please see the section User Access Rights.

Channel Unit Configuration

Channel Unit Types

For each type of sensor channel, define the unit in which data is displayed. If defined on probe, group, or device level, these settings can be inherited to all sensors underneath. You can set units for the following channel types (if available):

  • Bandwidth
  • Memory
  • Disk
  • File
  • Custom

icon-i-roundCustom channel types can be set on sensor level only.

Toplists

For all flow and packet sniffer sensors there are Toplists available on the Overview tab of a sensor's detail page. Using toplists, you can review traffic data of small time periods in great detail. For more information, please see Toplists section.

Filter Rules

The following filter rules apply to all xFlow, IPFIX, and Packet Sniffer sensors.

Field

Possible Filter Values

IP

IP address or DNS name (see Valid Data Formats)

Port

Any number

SourceIP

IP address or DNS name (see Valid Data Formats)

SourcePort

Any number

DestinationIP

IP address or DNS name (see Valid Data Formats)

DestinationPort

Any number

Protocol

TCP, UDP, ICMP, OSPFIGP, any number

TOS

Type Of Service: any number

DSCP

Differentiated Services Code Point: any number

The following filter rules apply to NetFlow V9 sensors only.

Field

Possible Filter Values

Interface

Any number

ASI

Any number

InboundInterface

Any number

OutboundInterface

Any number

SenderIP

IP of the sending device. This is helpful if several devices send flow data on the same port, and you want to divide the traffic of each device into a different sensor channel.

Possible values: IP address or DNS name (see Valid Data Formats)

SourceASI

Any number

DestinationASI

Any number

MAC

Physical address

SourceMAC

Physical address

DestinationMAC

Physical address

Mask

Mask values represent subnet masks in with a single number (number of contiguous bits).

DestinationMask

Mask values represent subnet masks in with a single number (number of contiguous bits).

NextHop

IP address or DNS name (see Valid Data Formats)

VLAN

VLAN values represent a VLAN identifier (any number)

SourceVLAN

VLAN values represent a VLAN identifier (any number)

DestinationVLAN

VLAN values represent a VLAN identifier (any number)

More

Knowledge Base: Where is the volume line in graphs?

Knowledge Base: What is the Active Flow Timeout in Flow sensors?

Edit Sensor Channels

To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, please see the Sensor Channels Settings section.

Notifications

Click the Notifications tab to change notification triggers. For detailed information, please see the Sensor Notifications Settings section.

Others

For more general information about settings, please see the Object Settings section.

Sensor Settings Overview

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

Related Topics

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