}
1) If your ISP assigns a private IP address (192.168.x.x, 10.x.x.x, or 172.16.x.x)
instead of a public IP address to the Device, DDNS will not work.
2) DDNS feature can help you implement VPN tunnels using dynamic IP addresses
on the Device.
4.6
UpnP
The Universal Plug and Play (UPnP) is architecture that implements zero
configuration networking, that is, it provides automatic IP configuration and dynamic
discovery of the UPnP compatible devices from various vendors. An UPnP compatible
device can dynamically join a network, obtain an IP address, announce its name,
convey its capabilities upon request, and learn about the presence and capabilities of
other devices on the network.
The Device can implement NAT traversal by enabling UPnP. When you enable UPnP,
the Device allows any LAN UPnP-enabled device to perform a variety of actions,
including retrieving the public IP address, enumerate existing port mappings, and add
or remove port mappings. By adding a port mapping, an UPnP-enabled device opens
the related service ports on the Device to allow the Internet hosts access. Windows
Messenger is an example of an application that supports NAT traversal and UPnP.
The Device provides
the
UPnP Port Forwarding List
, which lists all the port
forwarding rules established using UPnP. You can view each port forwarding
rule’s
detailed information in the list, which includes internal IP address, internal port,
protocol, remote IP address, external port, and description.
Figure 4-25 UPnP
