In this article we will cover the steps in designing a secure DMZ (demilitarized zone). The idea behind the secure DMZ is that your company has certain assets (web, mail, ftp, dns, etc) that need to be accessible from a public (untrusted) network while still maintaining a certain level of security of these assets and your secured private (trusted) network. By placing the assets in a secured DMZ, only approved access as outlined in the companies security policy is allowed into the DMZ from both the public and private networks making the assets less vulnerable to being compromised by an attacker from the public network than if they were just placed directly on the outside network. At the same time the secured DMZ insures the integrity of the private network since no security holes will need to be opened in the firewall to the private network for access to these assets.