Cannot see any netflow traffic for the 3 devices, it says " never" for the netflow received....icmp is not allowed for the said 3 devices? is it the cause why we could not see any netflow traffic? because port 2055 is already allowed on the firewall, only the icmp is not allowed.
With the other device, the last netflow received is 6/16 until now we could not see any netflow traffic......this device is behind the firewall. And should not be passing through the firewall.
I suggest the following: