ZyXEL Communications 310 6.6.2 Trigger Port Forwarding Process, 1.Jane requests a file from the Real Audio server, Figure 6-25Trigger Port Forwarding Process — Example

Prestige 310 Broadband Sharing Gateway

FIELD	DESCRIPTION	EXAMPLE
End Port	Enter a port number or the ending port number in a range of port numbers.	7170
Trigger	Trigger is a port (range) your Prestige checks to “remember” a computer IP
	address on the LAN when it sends traffic from the LAN to the WAN. It is the
	“listening” port of the server on the WAN side.
Start Port	Enter a port number or the starting port number in a range of port numbers.	7070
End Port	Enter a port number or the ending port number in a range of port numbers.	7070

Press [ENTER] at the message “Press ENTER to Confirm...” to save your configuration, or press [ESC] at any time to cancel.

6.6.2 Trigger Port Forwarding Process

The following is an example of trigger port forwarding.

.

Figure 6-25 Trigger Port Forwarding Process — Example1.Jane requests a file from the Real Audio server.

2.Port 7070 is a trigger port the Prestige uses to remember Jane’s computer IP address.

3.The Real Audio server responds using a port number ranging between 6970-7170.

4.The Prestige associates this “incoming” port with the trigger port, remembers Jane’s computer IP address and then forwards the traffic to her computer.

5.Only Jane can connect to the Real Audio server until the connection is closed or times out1.

1The Prestige will time out in three minutes when using UDP (User Datagram Protocol); two hours when using TCP/IP (Transfer Control Protocol/Internet Protocol).

6-24 Network Address Translation (NAT)