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.