In Splynx NetFlow accounting provides ability to record and process customer traffic statistics that was collected from NetFlow exporters, more specifically - from NAS devices added as Routers to Splynx.
5th version of NetFlow protocol data to calculate statistic information of
TCP packets that passed through your network and was and exported by your NAS device.
Once Router is added and NetFlow accounting is chosen for your NAS in
Networking → Routers - Splynx will be open to receive and process NetFlow data from this device via
9995/UDP port by default (can be changed in settings).
Depending on the data received from Router, Splynx is able to mark customer sessions as online and display amount of collected traffic for the session.
On MikroTik devices there is an ability to configure router as NetFlow exporter by configuring Traffic Flow.
In Splynx, navigate to
Networking → Routers, press
Add, specify the router IP and Accounting type:
NetFlow accounting will only work if the SRC IP in NetFlow packets originating from router is the same as IP/Host field value on router's info Splynx page, it will not work if router's outgoing traffic is translated (NAT) to IP that is different from what is entered in IP/Host field. It's better to connect your router with built-in OpenVPN feature for NAS and Splynx to be in the same network.
Customers → List, open the necessary customer's profile, click on the Services tab and open the window to edit their Internet service. Specify the router that this service is connected to, the IP assignment method (pool or static) and the IP address:
If we use Radius on our router to authorize customers, we should disable Radius accounting for services that must be counted by NetFlow:
On the MikroTik device, navigate to
IP → DHCP Server → DHCP (tab) → DHCP Config and disable the
PPP → Secrets (tab) → PPP Authentication & Accounting and disable the
Accounting option there:
IP → Hotspot, click on the Server Profiles tab, choose your profile and disable the
On the MikroTik device, navigate to
IP → Traffic Flow, put the check-mark to enable the setting and set the value in the Cache Entries field. Make sure this value is at least
128k, you can increase this value, but this depends on the amount of built-in RAM of the router.
On the MikroTik device, in the Traffic Flow Settings window, click on the Targets button and add Splynx as the traffic flow target:
9995 and select the Version value -
Once the Traffic Flow is enabled on MikroTik router, please wait 5-10 minutes for traffic to appear.
The traffic should be counted from the first finished flow that MikroTik sent to the Splynx
Config → Networking → NetFlow accounting we can change its Daemon and Expire options:
|Time in seconds when the accounting of the session will be stopped if there is no traffic. The default value is 450 seconds.
|Max session time
|Time in hours when large sessions will be spitted into smaller ones in the statistics. The default value is 24 hours.
|Min bytes for accounting
|if the accounting package shows that the used traffic is less than the indicated value (1024 bytes by default), such a package will be declined.
|Specifies the time interval in seconds to rotate files. The default value is 300 seconds.
|Specifies the port number to listen. Default port is 9995.
|Set size limit for the directory. The specified limit accepts values such as 100M, 100MB, 1G, 1.5G etc. Accepted size factors are K, KB, M, MB, G, GB and T, TB.
|Sets the max lifetime for files in the directory. The supplied maxlife_time accepts values such as 31d, 240H 1.5d etc. Accepted time scales are w (weeks) d (days) H (hours).
Check the daemon state and log data
Splynx uses some scripts from the
nfdump package to calculate traffic. The daemon
nfcapd listens to the port and the data can be received there.
When the interval for data collection ends, the data will be written to a file. After that the console script
./var/www/splynx/system/scripts/accounting-netflow is started, it runs
nfdump process with the specific parameters, script gets a response and converts it in the acceptable format for Splynx Accounting Processor.
To check if the
nfcapd daemon is running:
ps -aux | grep nfcapd
nfcapd daemon is written to syslog:
sudo tail -f /var/log/syslog | grep nfcapd
Review collected traffic via CLI
nfcapd is configured to save collected traffic to
/tmp/nfcapd/ folder. For each router there is subfolder named
router_ with corresponding number value at the end that is
ID of the router in Splynx.
To display all present collected data from router with
ID:1 and service with
IP 192.168.1.25 you can use the following command:
nfdump 'host 192.168.1.25' -R /tmp/nfcapd/router_1/ -A proto,srcip,dstip,srcport,dstport -O bytes
You can add
-t key to display collected flows of specific time period, for example from
nfdump 'host 192.168.1.25' -t 2023/01/25.00:00:00-2023/01/26.00:00:00 -R /tmp/nfcapd/router_1/ -A proto,srcip,dstip,srcport,dstport -O bytes
Missing of MAC and Session ID values in the customer's Internet statistics
In the customer's Internet sessions statistics you can notice that the last two sessions are listed without MAC and Session ID values. This is a common condition due to a limitation in
5th version of NetFlow, which results in such data not being passed to Splynx.