Draytek Vigor2620 LTE Series User Manual page 143

Choose IP Click this button and then a window will automatically pop
up, as depicted below. The window consists of a list of
private IP addresses of all hosts in your LAN network. Select
one private IP address in the list to be the DMZ host.
When you have selected one private IP from the above
dialog, the IP address will be shown on the screen. Click OK
to save the setting.
After finishing all the settings here, please click OK to save the configuration.
Vigor2620 Series User's Guide 131