Which is the best open-source Linux-based firewall for a small organization?

Firewalls serve as essential network security devices designed to monitor incoming and outgoing traffic, establishing a barrier between trusted and untrusted networks to protect against cyber threats. Firewalls, critically important in IT infrastructure, offer a range of security features that include packet filtering, stateful inspection, and proxy service. They are used extensively to define policies that allow or block traffic, playing a crucial role in preventing unauthorized access....