We’re big fans of the open-source firewall and router operating system OPNsense here at XDA, for many reasons, not the least of which is its commitment to the FOSS community. Many of us have replaced our primary router with OPNsense; others use it exclusively in our home labs, as it runs on (almost) everything that has two or more network interfaces, and it’s a powerful, configurable upgrade from the barely-there security of consumer routers.