In computer networking, DMZ is a firewall configuration for 
securing local area networks (LANs). 
In a DMZ configuration, most computers on the LAN run 
behind a firewall connected to a public network like the 
Internet. One or more computers also run outside the 
firewall, in the DMZ. Those computers on the outside 
intercept traffic and broker requests for the rest of the 
LAN, adding an extra layer of protection for computers 
behind the firewall. 

Traditional DMZs allow computers behind the firewall to 
initiate requests outbound to the DMZ. Computers in the DMZ 
in turn respond, forward or re-issue requests out to the 
Internet or other public network, as proxy servers do. 
(Many DMZ implementations, in fact, simply utilize a proxy 
server or servers as the computers within the DMZ.) The LAN 
firewall, though, prevents computers in the DMZ from 
initiating inbound requests. 

DMZ is a commonly-touted feature of home broadband routers. 
However, in most instances these features are not true 
DMZs. Broadband routers often implement a DMZ simply 
through additional firewall rules, meaning that incoming 
requests reach the firewall directly. In a true DMZ, 
incoming requests must first pass through a DMZ computer 
before reaching the firewall.

A DeMilitarised Zone (DMZ) is a seperate network located in 
the neutral zone between a private (inside) network and a 
public (outside) network