What is a network security firewall?

A Network Security Firewall is a security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules. Its primary purpose is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet, to prevent unauthorized access and cyber threats. Firewalls can be hardware-based, software-based, or a combination of both, and are a fundamental component of an organization's cybersecurity strategy.