What is a firewall?

A firewall is a network security device that monitors and filters incoming and outgoing network traffic based on an organization’s previously established security policies. At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet. Its main purpose is to allow non-threatening traffic in and to keep dangerous traffic out. There are several types of firewalls that have developed over time, including packet-filtering firewalls, stateful inspection firewalls, proxy firewalls, and next-generation firewalls. These can be implemented in hardware, software, or a combination of both. Firewalls are crucial components of network security, protecting the network from various threats by controlling traffic and preventing unauthorized access from outside the network.