Firewall

A firewall is a computer network security system that restricts internet traffic in to, out of, or within a private network.

This software or dedicated hardware-software unit functions by selectively blocking or allowing data Packet|packets. It is typically intended to help prevent malicious activity and to prevent anyone—inside or outside a private network—from engaging in unauthorized web activities.

Firewalls can be viewed as gated borders or gateways that manage the travel of permitted and prohibited web activity in a private network. By comparison, network security firewalls are for web traffic management — typically intended to slow the spread of web threats.

Firewalls create 'choke points' to funnel web traffic, at which they are then reviewed on a set of programmed parameters and acted upon accordingly. Some firewalls also track the traffic and connections in audit logs to reference what has been allowed or blocked.

Firewalls are typically used to gate the borders of a private network or its host devices. As such, firewalls are one security tool in the broader category of user access control. These barriers are typically set up in two locations — on dedicated computers on the network or the user computers and other endpoints themselves (hosts).