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Configuring Advanced Settings
–
Custom
You can specify your own service filter here.
Specifying an own service filter
The services in the list are blocked for Internet access. The specified service filter applies
to all clients. To create a service filter, proceed as follows:
ì
Select the services that are to be blocked.
– Select predefined services from the
Predefined applications
list. The most pop-
ular Internet services are offered.
Or
– Specify your own services manually.
Select the
Protocol
and enter the appropriate port number or port range in the
Port start
and
Port end
fields. To define one single port enter the same number
in both fields.
Entering a
Comment
that is displayed will help you to identify different services.
Enable the
Filter
checkbox to use the respective service for the service filter.
ì
Click
Add
to create a new entry with the entered data or for the selected, predefined
application.
ì
Click
Delete
to delete an entry.
ì
When you have completed all the settings in this screen, click
OK
to apply them.
Setting up the NAT function
The router Gigaset 504 AGU 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 applications
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.
