Which type of firewall is built into many operating systems?

The correct answer is Host-based firewall. A host-based firewall is integrated into the operating system of a computer or device to monitor and control incoming and outgoing traffic based on predetermined security rules. This type of firewall is designed to protect individual hosts by filtering traffic directly on the device, which helps defend against unauthorized access or harmful traffic.

Host-based firewalls are especially effective for personal computers and servers, providing an additional layer of security by managing traffic at the device level. Users can configure settings based on their specific needs, which is crucial for personal protection and securing sensitive data.

In contrast, other firewall types such as packet-filtering firewalls and stateful firewalls can be found in standalone devices or dedicated appliances rather than directly built into an operating system. Next-generation firewalls incorporate additional features like application awareness and deep packet inspection, and while they provide advanced functionality, they are not typically embedded within the operating systems themselves. This distinction underscores the unique role of host-based firewalls as part of the security architecture for individual systems.