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.