- Billion ADSL2+ Wireless Router User's Manual

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5.3.6.1 Port Mapping
Application: Select the service you wish to configure
Protocol: Automatic when you choose Application from listbox or select a protocol type
which you want.
External Port & Internal Port: Enter the public port number & range you wish to
configure.
Internal IP Address: Enter the IP address of a specific internal server to which requests
from the specified port is forwarded.
Add: Click to add a new virtual server rule. Click again and the next figure appears.
Edit: Check the Rule No. you wish to edit and then click “Edit/Delete”.
Delete: Check the Rule No. you wish to delete, then click “Edit/Delete”.
Since NAT acts as a “natural” Internet firewall, your router protects your network from
access by outside users, as all incoming connection attempts point to your router unless
you specifically create Virtual Server entries to forward those ports to a PC on your network.
When your router needs to allow outside users to access internal servers, e.g. a web server,
FTP server, Email server or game server, the router can act as a “virtual server”. You can
set up a local server with a specific port number for the service to use, e.g. web/HTTP (port
80), FTP (port 21), Telnet (port 23), SMTP (port 25), or POP3 (port 110). When an incoming
access request to the router for a specified port is received, it is forwarded to the
corresponding internal server.
For example, if you set the port number 80 (Web/HTTP) to be mapped to the IP Address
192.168.1.2, then all incoming HTTP requests from outside users are forwarded to the local
server (PC) with the IP address of 192.168.1.2. If the port is not listed as a predefined
application, you need to add it manually.