Step 1 Type in the default IP address of the router in your browser (default IP is 192.168.1.1)
Step 2 Log in using the default username and password (username: admin, password: admin)
Step 3 Click on Advanced at the top of the screen and then click on the Firewall and DMZ option on the left.
Step 4 In the DMZ Settings, check the 'Enable DMZ' option. Enter the IP Address that you want in the DMZ.
Step 5 Click on the Apply Settings button at the bottom of the screen.
Step 6 Click on the Reboot button on the left to reboot the router with the new settings.