Perimeter Network

A perimeter network is often referred to as a DMZ (demilitarized zone) network. The process of packet filtering is often involved in separating more trusted networks from DMZ networks at the perimeter. It may also separate the internet from a perimeter network. This allows an untrusted user to enter the DMZ but keeps them out of the trusted network. For instance, packet filtering may permit an HTTP request from the web to reach the DMZ, but prevent protocols that may leave a trusted network vulnerable to attacks. Perimeter networks are generally found in small LAN environments that connect internal routers with border routers. In more basic environments, the DMZ may be the most trusted area of a network. This is true with some ISPs (Internet Service Providers) that attach their border routers and servers to a single LAN. In this scenario, the perimeter network is the only network present.