A firewall is a security system that controls the incoming and outgoing network traffic based on a set of rules and protocols. It acts as a barrier between a private internal network and the public Internet.
Firewalls can be hardware-based or software-based, and can be implemented on different points of the network such as at the router level, at the host level (on each individual device), or as a cloud-based service.
It’s important to note that firewall is one of many security measures that should be considered when building and maintaining a secure network.
In simple terms, a firewall is like a guard at a gate, it inspects and controls the traffic that enters and leaves the network. It allows or blocks the traffic based on the rules and protocols set by the administrator, and prevents unauthorized access or malicious attacks from entering the network, thus providing an extra layer of security to the network.