netfloow free linux

netfloow free linux

Hello, please tell me. I downloaded and installed netflow analyzer on Linux. When installation is not an option netflow analyzer, netflow server and only netflow collector. I chose the collector installation. But when the period of 30 days has expired, he refused to work and the necessity of the license. I only have 2 interface, so I need a free version. 
I think that maybe I installed the wrong version. Please tell me that I need to install or how to get a free license?
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