An organizations network can be divided into two zones:
Uncontrolled Zone: Network outside the organizations control (Internet, WAN)
Controlled Zone: Subnet that protects internal network from uncontrolled zone
De-militarized Zone (DMZ)
Also called Screened Subnet, Perimeter Network or Extranet
Public facing services that can access the internet
Web Servers, Proxy Servers, DNS Servers, Email and File Servers
Internal Network (Intranet)
Internal Private Network that the organization needs to protect
Used for internal business
Outside users (Internet, Extranet) cannot access resources on the Intranet
Restricted Zone
Private network that only business partners an access
Used to store highly confidential and sensitive information
Only accessible from Intranet
