First, there are two types of DMZs.
- In a three-homed perimeter network, the firewall has three network connections. One for connection to the Internet, one for connection to your network and a third, the DMZ on which you place your Web server and other Internet-facing servers.
- In a second type of DMZ, the back-to-back perimeter network, you use two firewalls, each with two network connections. One firewall, the Internet facing firewall, has a network connection to the Internet and another to the DMZ network. The second firewall has a connection to the DMZ network and then to your Internal network. In this type of DMZ, the DMZ network is sandwiched between your network and the Internet.
This was first published in April 2003