A firewall is a network security system that monitors, controls, and filters 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, helping to prevent unauthorized access and cyberattacks.
Firewalls can be hardware-based, software-based, or a combination of both. They are commonly used in home networks, business networks, and data centers to protect computers, servers, and sensitive data.
Firewalls work by analyzing data packets and determining whether to allow or block them based on rules set by the network administrator. They can prevent threats such as malware, hackers, and unauthorized data access, while also controlling the types of applications and services that can communicate over a network.
Advanced firewalls, like next-generation firewalls (NGFW), offer additional features such as intrusion detection, application awareness, and deep packet inspection for enhanced security.