I'd like to offer an introduction into Network System Monitoring using different open tools available in linux. The talk is a technical approach to identify the best sniffing points in a network and how to orchestrate a full analysis of the content to secure the network, as well as showing ideas of collaborative and distributed hacking.Also, for a better performance, the talk includes a brief guide into configuring a Raspberry PI for creating a simple Network Capture Probe.The main point of the talk is to show how open source tools are a nice option for this kind of security assessment.