Software firewalls are security applications installed on individual devices, servers, or virtual environments to monitor and control incoming and outgoing network traffic. Unlike hardware firewalls, which protect entire networks, software firewalls operate at the device level, filtering traffic based on user-defined rules, applications, and ports. Common examples include Windows Defender Firewall, ZoneAlarm, and Sophos Endpoint Firewall. They are cost-effective, easy to deploy, and flexible enough to be installed across multiple systems quickly, making them ideal for small businesses and individual users. Software firewalls provide features such as stateful packet inspection, application-level filtering, activity logging, and real-time alerts to prevent unauthorized access. They can also integrate with antivirus software and endpoint security platforms to provide layered protection against malware and cyber threats. In cloud and virtualized environments, software firewalls help secure workloads on platforms such as AWS and Microsoft Azure. However, their effectiveness is limited by the computing resources of the host system, as high network traffic may impact performance. While not as robust as hardware firewalls, software firewalls remain an essential layer of defense for endpoint protection, especially in scenarios where affordability, flexibility, and device-level control are required.