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Configuring Advanced Settings
Gigaset SX763 WLAN dsl / en AnnA / A31008-M707-R131-1-7619 / configure_router.fm / 20.07.2006
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hablone 2
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– Click
Add
to create a new entry with the entered data or for the selected, prede-
fined application.
– Click
Delete
to delete an entry.
ì
Click
OK
to apply the settings.
Setting up the NAT function
The Gigaset SX763 WLAN dsl comes equipped with the NAT (Network Address Transla-
tion) function. With address mapping, several users in the local network can access the
Internet via one or more public IP addresses. All the local IP addresses are assigned to
the router's public IP address by default.
One of the characteristics of NAT is that data from the Internet is not allowed into the
local network unless it has been explicitly requested by one of the PCs in the network.
Most Internet applications can run behind the NAT firewall without any problems. For
example, if you request Internet pages or send and receive e-mails, the request for data
from the Internet comes from a PC in the local network, and so the router allows the
data through. The router opens precisely
one
port for the application. A port in this con-
text is an internal PC address, via which the data is exchanged between the Internet and
a client on a PC in the local network. Communicating via a port is subject to the rules of
a particular protocol (TCP or UDP).
If an external application tries to send a call to a PC in the local network, the router will
block it. There is no open port via which the data could enter the local network.
Some applications, such as games on the Internet, require several links, i.e. several
ports so that the players can communicate with each other. In addition, these applica-
tions must also be permitted to send requests from other users on the Internet to users
in the local network. These applications cannot be run if Network Address Translation
(NAT) has been activated.
Using port forwarding (the forwarding of requests to particular ports) the router is
forced to send requests from the Internet for a certain service, for example a game, to
the appropriate port(s) on the PC on which the game is running.
When the Gigaset SX763 WLAN dsl is supplied, the
Translation) is activated, i.e. all IP addresses of PCs in the local network are converted to
the router's public IP address when accessing the Internet.
