Firewall
A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet, to prevent unauthorized access, protect against malicious activities, and ensure the confidentiality, integrity, and availability of data. Firewalls can be hardware-based, software-based, or a combination of both, and they play a crucial role in protecting networks and devices from cyber threats.