What Does a Firewall Actually Do?

You may have heard that firewalls are an important security protection, but do you know why? Many people don’t, as evidenced by references to firewalls in television shows, movies, and other forms of popular media.

A firewall sits between your computer (or local network) and another network (such as the Internet) and monitors incoming and outgoing network traffic. Without a firewall, anything is possible. In a firewall, firewall rules determine which traffic is allowed and which is not.

Definition of a firewall

A firewall is a security device — a piece of hardware or software — that helps protect your network by filtering traffic and preventing unauthorized access to private data on your computer by unauthorized people. Not only does a firewall block unwanted traffic, but it also helps prevent malware from infecting your computer.

Firewalls can provide different levels of protection. It is important to decide how much protection you need. The following topics will help you understand what a firewall does and determine which level of protection will help you protect your computer and the data it contains.

Types of firewalls

There are software and hardware firewalls. Each serves a different but important purpose. A hardware firewall is physical, like a broadband router – it sits between your network and the gateway. A software firewall is internal – it’s a program on your computer that works through ports and applications.

There are also cloud-based firewalls, known as Firewall as a Service (FaaS). One of the advantages of cloud-based firewalls is that they can grow with your organization and handle perimeter security as well as a hardware firewall. There are different types of firewalls, depending on their architecture and functionality. Here are the different firewalls you can use, depending on the size of your network and the level of security you need.

Hardware firewalls vs. software firewalls 

There are two types of firewalls you should know about: hardware firewalls and software firewalls. As the name implies, a hardware firewall is a physical device that can be compared to a network router because it filters network traffic. Its purpose is to protect your network and endpoints. In contrast, hardware firewalls attempt to protect your entire network with a single device. This makes them vulnerable to attacks on network interconnections.

Using a software firewall is a more detailed approach because it involves installing a firewall on an existing individual local device. Software firewalls are usually included in antivirus software and operating systems and work in the same way as hardware firewalls. They monitor and filter traffic, but only for specific end devices.