PRTG Manual: sFlow (Custom) Sensor
The sFlow (Custom) sensor receives traffic data from an sFlow V5 compatible device and shows the traffic by type. Please make sure the device matches the sFlow version V5! There are several filter options available 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.
Dutch: sFlow (Custom), French: sFlow (personnalisé), German: sFlow (Benutzerdef.), Japanese: sFlow(カスタム), Portuguese: sFlow (customizado), Russian: sFlow (нестандартный), Simplified Chinese: sFlow (自定义), Spanish: sFlow (Personalizado)
- You must enable sFlow V5 export 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).
- The sensor accepts RAW data.
- 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.
- There are several limitations for this sensor type.
- Paessler Website: Paessler sFlow Tester
- Knowledge Base: Where is the volume line in graphs?
- For a general introduction to the technology behind flow monitoring, see section Monitoring Bandwidth via Flows.
- This sensor type can have a high impact on the performance of your monitoring system. Please use it with care! We recommend that you use no more than 50 sensors of this sensor type on each probe.
You cannot add this sensor type to the Hosted Probe of a PRTG hosted by Paessler instance. If you want to use this sensor type, please add it to a remote probe device.
Limitations of This Sensor Type
There are some limitations that you want to consider before using this sensor type:
- Only sFlow version 5 datagrams are supported
- Only IPv4 flows are supported
- Only the "raw packet header" format is supported
- Only the "Flow sample" and "Extended flow" formats are supported. "Counter" formats cannot be processed
- PRTG processes only samples where the source ID matches the ifIndex of the input interface (avoiding double counted traffic) and ascending sequence numbers.
- Sample packets have to be of ethernet type "IP" (with optional VLAN tag)
- Sampled packets of type TCP and UDP are supported
We recommend that you use the sFlow tester for debugging. Please download it here: Paessler sFlow Tester
PRTG does not officially support more than 50 sensor channels. 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.
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.
On the details page of a sensor, click the Settings tab to change its settings.
Usually, 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. See below for details on available settings.
Basic Sensor Settings |
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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.
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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). |
sFlow Specific Settings |
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Receive sFlow 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 sFlow export options of your hardware router device. Default value is 6343. Please enter an integer value.
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Sender IP |
Enter the IP address of the sending device you want to receive the sFlow 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 sFlow Packets on IP |
Select the IP address(es) on which PRTG listens to sFlow packets. The list of IP addresses shown here is specific to your setup. To select an IP address, add a check mark in front of the respective line. The IP address selected here must match the one configured in the sFlow export options of your hardware router device.
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Channel Definition |
Enter a channel definition to divide the traffic into different channels. Write each definition in one line. All traffic for which no channel is defined will be accounted to the default channel named Other.
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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:
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Filtering |
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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.
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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.
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Sensor Display |
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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.
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Graph Type |
Define how different channels will be shown for this sensor.
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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 |
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Primary Toplist |
Define which will be your primary Toplist. It will be shown in maps when adding a toplist object. Choose from:
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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, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.
Scanning Interval |
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Click |
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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 to 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:
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Schedules, Dependencies, and Maintenance Window |
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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.
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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 status instead. Choose between:
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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:
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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.
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Access Rights |
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Click |
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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:
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.
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Channel Unit Configuration |
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Click |
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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):
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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, see section Toplists.
The following filter rules apply to all xFlow, IPFIX, and Packet Sniffer sensors.
Field |
Possible Filter Values |
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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 sFlow sensors only.
Field |
Possible Filter Values |
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Interface |
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) |
MAC |
Physical address |
SourceMAC |
Physical address |
DestinationMAC |
Physical address |
Paessler Website: Paessler sFlow Tester
Knowledge Base: Where is the volume line in graphs?
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, see the Sensor Channel Settings section.
Click the Notification Triggers tab to change notification triggers. For detailed information, see the Sensor Notification Triggers Settings section.
For more general information about settings, see the Object Settings section.
For information about sensor settings, see the following sections: