A firewall is a protective system that lies, in essence, between your computer network and the Internet. When used correctly, a firewall prevents unauthorized use and access to your network. The job of a firewall is to carefully analyse data entering and exiting the network based on your configuration. It ignores information that comes from an unsecured, unknown or suspicious locations. A firewall plays an important role on any network as it provides a protective barrier against most forms of attack coming from the outside world. Firewalls can be either hardware or software. The ideal firewall configuration will consist of both. In addition to limiting access to you computer and network, a firewall is also useful for allowing remote access to a private network through secure authentication certificates and logins.