In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted network and an untrusted network, such as the Internet.

What is a firewall on a computer?

A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules.

What is a firewall in simple terms?

A firewall is a computer network security system that restricts internet traffic in, out, or within a private network. ... It is typically intended to prevent anyone—inside or outside a private network—from engaging in unauthorized web activities and to help prevent malicious activity.