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Demilitarized Zone in Computer Networking

Using a Demilitarized Zone on Computer Networks

By Bradley Mitchell Bradley Mitchell Writer Massachusetts Institute of Technology University of Illinois An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. lifewire's editorial guidelines Updated on March 23, 2020 Tweet Share Email Tweet Share Email Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless In computer networking, a demilitarized zone is a special local network configuration designed to improve security by segregating computers on each side of a firewall. A DMZ can be set up either on home or business networks, although their usefulness in homes is limited. Lane Oatey / Blue Jean Images/Getty Images

Where Is a DMZ Useful

In a home network, computers and other devices typically are configured into a local area network connected to the internet using a broadband router. The router serves as a firewall, selectively filtering traffic from the outside to help ensure only legitimate messages pass through. A DMZ divides such a network into two parts by taking one or more devices inside the firewall and moving them to the outside. This configuration better protects the inside devices from possible attacks by the outside (and vice versa). A DMZ is useful in homes when the network is running a server. The server could be set up in a DMZ so that internet users could reach it through its public IP address, and the rest of the home network was protected from attacks in cases where the server was compromised. Years ago, before cloud services became widely available and popular, people more commonly ran Web, VoIP, or file servers from their homes and DMZs made more sense. Business computer networks, on the other hand, can more commonly use DMZs to help manage their corporate web and other public-facing servers. Home networks nowadays more commonly benefit from a variation of DMZ called DMZ hosting.

DMZ Host Support in Broadband Routers

Information about network DMZs can be confusing to understand at first because the term refers to two kinds of configurations. The standard DMZ host feature of home routers does not set up a full DMZ sub-network but instead identifies one device on the existing local network to function outside the firewall while the rest of the network functions as normal. To configure DMZ host support on a home network, log into the router console and enable the DMZ host option that is disabled by default. Enter the private IP address for the local device designated as the host. Xbox or PlayStation game consoles are often chosen as DMZ hosts to prevent the home firewall from interfering with online gaming. Ensure the host uses a static IP address (rather than a dynamically assigned one), otherwise, a different device may inherit the designated IP address and become the DMZ host instead.

True DMZ Support

In contrast to DMZ hosting, a true DMZ (sometimes called a commercial DMZ) establishes a new sub-network outside the firewall where one or more computers run. Those computers on the outside add an extra layer of protection for computers behind the firewall as all incoming requests are intercepted and must first pass through a DMZ computer before reaching the firewall. True DMZs also restrict computers behind the firewall from communicating directly with DMZ devices, requiring messages to come through the public network instead. Multi-level DMZs with several layers of firewall support can be set up to support large corporate networks. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire Can't Connect to the Internet? Try These 10 Tips Port Numbers Used for Computer Networks What Is an IP Address? How to Set Up Port Forwarding How to Set Up a Router How to Connect Two Routers on a Home Network Private IP Addresses: Everything You Need to Know How to Set Up Networks for Digital Devices How to Use an IP Address to Find a MAC Address How to Fix Client and Server-Side VPN Error 800 What Is Computer Networking? Wired vs. Wireless Networking How to Fix It When Nintendo Switch Won't Connect to Wi-Fi What Is an Uplink Port in Computer Networking? How to Set Up PPPoE Internet Access 192.168.2.1 Default IP Address for Some Home Network Routers Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies