What is a Firewall?
A firewall is a network security device that monitors and controls incoming and outgoing network traffic. A firewall provides security at the perimeter by monitoring incoming and outgoing data packets in network traffic for malware and anomalies. It filters traffic as it attempts to enter and exit your network. Depending on where it is deployed and its purpose, a firewall can be delivered as a hardware appliance, software, or software as a service (SaaS).
Types of Firewalls
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)