Ericsson W21 - Manual (Page 44)

Configuration and Management
2.7 NAT
The Ericsson W21 includes a NAT (Network Address Translation) service.
With this service several computers on a LAN/WLAN can share the same
Internet connection using a single public IP address.
Devices on the LAN/WLAN use dedicated private IP addresses, which
cannot be used on the Internet. When a computer on the LAN/WLAN want
to send a data package to the Internet, its IP address is automatically
translated by NAT to an external (public) IP address allowed on the
Internet. When a reply receives to this external IP address, it is translated
back to the original private IP address to be able to find its way back to the
sending computer on the LAN/WLAN.
In this way, details about the local devices remain private and it is not
possible to access a local computer on the LAN/WLAN directly from the
Internet.
Figure 30 - NAT page
2.7.1 UPnP IGD
The Ericsson W21 supports the Universal Plug and Play (UPnP) Internet
Gateway Device (IGD) standard. UPnP IGD is used to provide automatic
port forwarding allowing communication between certain Internet
42 1/1551-CRH 102 167 Uen Rev D 2007-11-16