We’ve all heard the term “firewall.” In fact, it’s the firewall that’s often blamed when a user can’t do something he wants to do (like stream Pandora at the office). “It’s that darn firewall… it needs to be changed.”
But what, really, is a firewall and what is it designed to do? A firewall sits between your local computer/computer network and the internet, and acts like a gatekeeper. More specifically, it is the part of a computer system or network that enforces security policies designed to block unauthorized access to your system from the outside, while permitting communication to the internet from the inside.
Where would you find it? Is it software on your computer? Is it software on your server? Is it a piece of equipment on your network? The answer is yes … to all three. In today’s world, firewalls have evolved to be a multi-tier threat-detection and prevention collection of policies, rather than a one-size-fits-all device. There are NAT firewalls, proxy firewalls, application firewalls, stateful firewalls and packet filter firewalls. Some of these are included in your internet firewall, some are included in your PC’s firewall, and some may even be included in your server’s firewall.