User`s guide

MN-500 Base Station Configuration Guide 19
Application-Triggered Port Forwarding
Some applications, such as Internet games and videoconferencing, require multiple ports for data transmission.
File Transfer Protocol (FTP) data, for example, is sent from your computer to one port and returns to another port.
These multiple port transmissions might cause problems when the base station is set to routing mode so that NAT
is enabled on your base station, because the NAT service anticipates that data sent to one port will return to the
same port.
The Broadband Networking Wired Base Station has already been configured to accommodate some common
application protocols that require multiple ports, including FTP, Simple Mail Transfer Protocol (SMTP), and Post
Office Protocol 3 (POP3).
To configure port forwarding for other applications that require multiple ports, you must specify the outbound
(destination) port to which data following a particular protocol will be sent, and the inbound (source) port or ports to
which related data will return. Essentially, you are telling the base station how to direct traffic across the networks.
The inbound ports that you specify will open only when data is sent to the corresponding outbound port. These
ports will close again after a certain amount of time has elapsed with no data sent to the inbound port.
You can set ranges of ports, multiple ports, and combinations of single and multiple ports for the inbound ports.
You can configure the base station to accommodate up to 50 applications. To identify the protocol that an
application uses and the ports to which the data should be sent, see the documentation for that application.
To establish application-triggered port forwarding
1. Open the Base Station Management Tool, and then click Security.
2. On the Security menu, click Port Forwarding, and then click Set up application-triggered port forwarding.
3. In the Description box, type a description of the application that you want to enable.
4. In the Outbound port box, type the number of the outbound port. The outbound port should be one number from
0 through 65535. To determine which port the application uses, consult the documentation for the application.
5. In the Trigger type drop-down list box, click the trigger type. The trigger type should be specified in the
documentation for the application.
6. In the Inbound port(s) box, type the inbound port. The inbound port can be a single port or a comma-separated
list of ports or port ranges. For example, you could type 4-25, or 243, or 10, 24-50, 74. You are limited to 256
characters.
7. In the Public type drop-down list box, click the public type. The public type should be specified in the
documentation for the application.
8. Select the Enable check box.
9. To save the changes you have made, click Apply, or to delete the changes, click Cancel.
If an application does not function correctly after you enable multiple ports, check the documentation for the
application to verify that you are enabling the correct ports to open. If you have set the correct ports to open and
the application still does not function properly, you might need to establish a virtual demilitarized zone (DMZ) on
one of the client computers on your network to run the application. For information about establishing a DMZ, see
“Virtual Demilitarized Zone.”
Persistent Port Forwarding
When you host a server on your network—for example, a Web or FTP server—you must configure the base station to
perform persistent port forwarding.
Persistent port forwarding is similar to application-triggered port forwarding in that you are opening inbound ports to
allow particular types of data or data requests to be sent from the Internet to one of the networked computers. The
difference is that you are opening these inbound ports permanently, rather than configuring them to open only
when there is data sent to an outbound port. In addition, you are directing the data sent to that port to a particular
computer on your local network.
For example, if you set up a Web server on one of the computers on your network, you must direct unsolicited
requests sent to Transmission Control Protocol (TCP) Port 80, which handles Hypertext Transfer Protocol (HTTP) or
Web data, to that computer. An unsolicited request is any data communication that is not initiated by a computer
on your local network.
Although not required, it is recommended that you have a static (fixed) IP address to host any type of server on your
network.