A firewall is a hardware or software network security device that sits at the juncture between two networks to control what information is allowed to pass between those networks. Usually, the two networks are an organization's internal network and the Internet. A firewall's primary role in information security is to protect computers on the internal network from intentional attacks that aim to:
So a firewall greatly reduces the risk of outside attacks corrupting information, compromising confidentiality or denying service. It DOES NOT protect computers on the network against viruses sent in email attachments or through web downloads and file transfers from removable media such as USB and Firewire drives.
In 2009, HSU established a "closed border configuration" firewall which: