Sams Teach Yourself TCP/IP in 24 Hours, Fourth Edition

The DMZ

The firewall provides a protected space for the internal network that is difficult to access from the outside. This concept works well for workgroups of web clients with a few scattered file servers filling internal requests. In many cases, however, an organization might not want to protect all its resources from outside access. A public web server, for instance, needs to be accessible from the outside. Many organizations also maintain FTP servers, email servers, and other systems that need to be accessible from the Internet. Although it is theoretically possible to open a port on the firewall to allow outside clients to access a specific service on a specific system, thus allowing the server to operate from inside the firewall, inviting ...