Think of your firewall as your house. Your home has doors and windows that can be opened or closed and even locked. Some doors may have advance locks that only allow specific individuals to come in or out. A firewall is a lot like that. Your firewall should have as many doors and windows closed as possible to prevent unwanted traffic from getting in or even out. A great thing about firewalls is that they are available for networking devices and for host stations. Your router, however, most likely also has a built-in firewall as well. The ability to have a firewall on the router and on each host highlights a security strategy called "Defense in Depth." The purpose of defense in depth is to have layers of security to make it more difficult for a bad actor to get into your network. Also, since there are so many layers of security, should one layer fail, you are not left unsecured. In fact, some security teams intentionally leave some doors open to learn more about the traffic, only to deny it later on, just before it gets dangerous. When it comes to firewalls, there a few different types available such as packet filtering, circuit level, stateful inspection, application level, and multi-level. Each has its own benefits and pitfalls. Your business must understand what it is trying to achieve before acquiring a firewall. Also, it takes a well-trained person to configure a firewall securely, let alone do so for the multiple manufacturers out there. Fortunately, no firewall is too great for Gray Space Defense.