It may happen that you have configured NetFlow export on a device but there is no NetFlow traffic in the application. This is manifested by empty charts and/or presence of dropped packets in System view. Possible causes are low memory, power outage on the server, network misconfiguration and more.
NetFlow traffic may not show due to several reasons:
Most of diagnostic information will be lost when you restart NetVizura. Use it as a last resort. Consult with support before restarting NetVizura. |
If all of the following steps are inconclusive and you cannot recover NetVizura to normal operational mode, consult article How to restart the application for steps on how to restart NetVizura.
Go to System tab in the application
tcpdump port 2055
command - you should see steady stream of packets received by the server (2055 is the default NetFlow port)watch -n1
"ls -l /var/lib/netvizura/flow/temp"
- after several seconds you should see that tmp.bin
file size is increasingtmp.bin
file size is not increasing, but tcpdump
shows that NetFlow packets are reaching the server check your local firewall configuration (usually iptables) or NetVizura NetFlow Collection port (see below).service iptables status
or firewall-cmd --list-all
to view firewall configuration. There has to be a line present which is allowing traffic on NetFlow port (2055)Execute command netstat -noap | grep 2055
and verify that there is a line present similar to following:
udp 0 0 :::2055 :::* 28004/java off (0.00/0/0) |
It is important that java process is the one that occupied NetFlow port - not some other process. If some other process already occupied NetFlow port you need to reconfigure that other process to use a different port.
Check that Collection port is accessible outside the NetVizura server
on a remote host execute command nmap netvizura_ip_address -sU -p 2055
where netvizura_ip_address is the address of NetVizura server. In the output of the command you should see that the port is open.
Using an administrator account on Windows is recommended. |
tmp.bin
file size is increasing (This is default location for NetVizura NetFlow installation)tmp.bin
file size is not increasing, but packet analyzer shows that NetFlow packets are reaching the server, check your local firewall configuration or NetVizura NetFlow Collection port (see below).netstat -noab
and verify that Tomcat process is the one that occupied NetFlow port 2055. If some other process already occupied NetFlow port you need to reconfigure that other process to use a different port.nmap -sU netvizura_ip_address -p 2055
where netvizura_ip_address is the address of NetVizura server. In the output of the command you should see that the port is open.