|  |  | Several widely available networking products can be used to secure the perimeter of the network. They create a "demilitarized zone" (DMZ) that exists to monitors and controls activities between the internal and external networks. A perimeter router may be installed with an Access Control list that allows or denies network traffic. A Proxy gateway or Application gateway is traffic filtering software that is loaded on a network server. A Firewall is also software that can be loaded on a server to filter network traffic. Let's look at each in more detail.