Port Range Forwarding; End Port; Start Port - Cisco DPC3825 User Manual

Configure Applications and Gaming
Section
Port Filtering
Applications & Gaming > Port Range Forwarding
Important: The gateway normally implements a feature called Port Translation. Port
Translation monitors what ports are actually being used by your PCs or other
devices on your LAN. This monitoring provides an added level of security beyond
what the firewall provides. However, there are some applications that require the
gateway to use specific ports to connect over the Internet.
Use Port Range Forwarding to forward ports from the public Internet to specific IP
addresses in your local network. Select the Port Range Forwarding tab to open the
Applications & Gaming Port Range Forwarding page.
For the Start and End Port, select a port from the recommended 49152 - 65535 range.
Keep in mind that ports used are program specific so check which ones the program
requires to be forwarded. Type the port number or range in both boxes. In the IP
Address box type the name of the computer's IP address to which this is to apply.
Note: Port Range Forwarding continually exposes the selected ports to the public
Internet. This means that the gateway's firewall is no longer active on these ports.
The device with the forwarding IP address can be exposed to hacker attacks while
the port range is being forwarded.
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Field Description

Start Port:

This is the beginning of the port range. Enter the beginning of the
range of port numbers (external ports) used by the server or Internet
application. Check with the software documentation of the Internet
application for more information if necessary.

End Port:

This is the end of the port range. Enter the end of the range of port
numbers (external ports) used by the server or Internet application.
Check with the software documentation of the Internet application
for more information if necessary.
Protocol
Select one of the following protocols:

TCP

UDP

Both
Enable:
Check this box to enable filtering on the specified ports.
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