Universal Plug and Play (UPnP) is an open networking standard that uses TCP/IP for simple peer-to-peer network connectivity between networking devices or software applications which have UPnP enabled. A UPnP device can dynamically join a network, obtain an IP address, advertise its services, and learn about other devices on the network. A device can also leave a network automatically when it is no longer in use.
*To use UPnP NAT-T, enable NAT in the Network Setting > Broadband > Edit or Add New WAN Interface screen.
Use the following screen to configure the UPnP settings on your Zyxel Device. Click Network Setting > Home Networking > UPnP to display the screen shown next.
Network Setting > Home Networking > UPnP
The following table describes the labels in this screen.
Network Settings > Home Networking > UPnP 
UPnP State
Select Enable to activate UPnP. Be aware that anyone could use a UPnP application to open the Web Configurator's login screen without entering the Zyxel Device's IP address (although you must still enter the password to access the Web Configurator).
UPnP NAT-T State
Select Enable to activate UPnP with NAT enabled. UPnP NAT traversal automates the process of allowing an application to operate through NAT. UPnP network devices can automatically configure network addressing, announce their presence in the network to other UPnP devices and enable exchange of simple product and service descriptions.
This field displays the index number of the entry.
This field displays the description of the UPnP NAT-T connection.
Destination IP Address
This field displays the IP address of the other connected UPnP-enabled device.
External Port
This field displays the external port number that identifies the service.
Internal Port
This field displays the internal port number that identifies the service.
This field displays the protocol of the NAT mapping rule. Choices are TCP or UDP.
Click Apply to save your changes.
Click Cancel to restore your previously saved settings.