Firewall #
Introduction #
A Firewall is a network security device that monitors and controls incoming and outgoing traffic from a computer network. By allowing only authorized traffic and blocking unwanted traffic, firewalls protect against unauthorized access, malware, and other security threats. A firewall in a computer network provides security at the perimeter by monitoring incoming and outgoing data packets in network traffic for malware and anomalies.
Firewalls have been a first line of defense in network security for over 25 years. They establish a barrier between secured and controlled internal networks that can be trusted and untrusted outside networks, such as the Internet. A firewall can be hardware, software, software-as-a service (SaaS), public cloud, or private cloud (virtual).
There are five main types of firewalls depending upon their operational method:
- Stateless or packet filtering firewall
- Stateful inspection firewall
- Circuit-level gateway
- Application-level gateway
- Next-generation firewall (NGFW)