There are several types of firewalls and each firewall has its own purposes. However, many experts categorize the different firewalls out there into two simple, main groupings: personal and commercial Personal firewalls are designed to provide protection to simple systems or a small network. Usually, personal firewalls do not require any special training or certifications; personal users can simply follow the instructions of these user-friendly firewalls over the web or through some other graphical user interface instructions that are readily available to them. Contrarily, commercial firewalls are little more complex as they are designed to protect medium to large businesses and they require specific training and certifications to take full advantages of their features.In addition, there are four other subcategories of firewalls such as personal hardware firewall, commercial hardware firewall, personal software firewall and commercial software firewall. Out of these subcategories, it is hard to really dissect which one is the best type of firewall because it really comes down to preferences, cost and the overall objective of that firewall. For example, it really makes no sense for a person that is operating a home network to purchase an expensive commercial firewall. For personal use, I will likely pick a hardware firewall because it is easy to operate and on top of that it is specifically built and hardened to support the functions of the firewall software running on it. In addition, a hardware firewall has dedicated hardware resources not shared with any other devices, important security features that can reduce vulnerabilities. A hardware firewall can also protect a single system or an entire network, all it needs is a single network connection and a power source. All these tenets are great security features that make a hardware firewall the best type of firewall.ExampleFor example,You surf the internet at home using an always-on broadband connection.You connect to the internet via a public WiFi network in a park, cafe or airport.You run a home network which needs to be kept isolated from the internet.You wish to be kept informed when any program on your computer attempts to connect to the internet.Most Personal Firewalls are highly configurable so you can easily create security policies to suit your individual needs.