Different Types of Firewalls
Firewalls protect your PC from unauthorized access by screening unsolicited data from the internet. Firewalls are based on pre-programmed rules that determine what traffic is allowed to come into or out of your computer. In other words, a firewall acts like a guard at a doorway to ensure no one can get into your house or car without permission.
In addition to checking the identity of incoming traffic (e.g., where it came from and where it’s attempting to go), firewalls can also check the contents of those packets. This can be helpful for preventing malicious code and data leaks.
Different types of firewalls are available based on network architecture, threat landscape, and operational needs. Some of the differences are simply technical trivia, but others reflect more advanced capabilities that improve detection and support for hybrid and multi-cloud environments.
Static packet-filtering firewalls operate at the OSI network layer (layer 3) and filter on the basis of specific criteria like IP addresses, ports, and basic packet protocols. This is the most basic type of firewall and, at a minimum, prevents two networks from connecting directly to each other without a firewall between them.
Unlike static packet-filtering firewalls, stateful inspection firewalls operate at the OSI network layer (4 or 5). These systems scan individual packets of data to look for certain patterns and evaluate the overall context of connections. This is how they are able to detect and block advanced threats that could pass through other filters.