It is crucial to choose the right hardware for your OPNsense, so that it functions well as a firewall, and the most important components are the CPU and the network interface cards (NICs). For example, choosing the right NIC for the network environment can make the difference between a successful deployment and a complete disaster. Of course, the high-quality code of OPNsense can do an outstanding job while securing networks, but without a good hardware bundle, it won't make any magic.

As we discussed in the last chapter, the kernel OPNsense runs on has the netmap framework implemented in it, which can be used by network IPS and Sunny Valley's Sensei plugin, for example, to process network packets with better performance and low CPU usage. If one of your OPNsense installation tasks uses one or maybe both of these (network IPS and Sensei plugin in different NICs), then you should choose a network card with a driver that is supported by netmap to...