Fighting malware and spam

Demilitarized Zone

Set of systems between internal and external networks

A demilitarized zone (DMZ) is a network positioned between a secure LAN and the external internet, allowing the separation of exposed services such as email and web hosting from the internal network.

Machines in the DMZ are usually server systems which are by their nature less secure than systems within the LAN - they need to allow access from outside to carry out web and mail transactions. Firewalls usually sit on either side of the DMZ filtering traffic, and those between the LAN and the DMZ will normally only allow initiation of connections from the inside, thus providing an extra layer of security should the systems in the DMZ be subjected to attack or compromised.

In some cases a single system is used as a combined firewall and DMZ, prozying all services.