It's no secret that we're big fans of OPNsense here at XDA. I've got two virtual machines with it running for testing purposes, plus I recently got a DEC750 OPNsense hardware firewall to save my brain ...

OPNsense is a powerful firewall forked from pfSense and based on FreeBSD. Although capable, many may find the software daunting when first starting with a custom firewall. OPNsense is pretty much good ...