ZyXEL Communications G-2000 Plus - Manual (Page 150)

ZyAIR G-2000 Plus User’s Guide
149 Chapter 10 Single User Account (SUA) / Network Address Translation (NAT)
Figure 60 Trigger Port Forwarding Process: Example
1 Jane requests a file from the Real Audio server (port 7070).
2 Port 7070 is a “trigger” port and causes the ZyAIR to record Jane’s computer IP address.
The ZyAIR associates Jane's computer IP address with the "incoming" port range of
6970-7170.
3 The Real Audio server responds using a port number ranging between 6970-7170.
4 The ZyAIR forwards the traffic to Jane’s computer IP address.
5 Only Jane can connect to the Real Audio server until the connection is closed or times
out. The ZyAIR times out in three minutes with UDP (User Datagram Protocol), or two
hours with TCP/IP (Transfer Control Protocol/Internet Protocol).
10.6.2 Two Points To Remember About Trigger Ports
1 Trigger events only happen on data that is going coming from inside the ZyAIR and
going to the outside.
2 If an application needs a continuous data stream, that port (range) will be tied up so that
another computer on the LAN can’t trigger it.
10.7 Configuring Trigger Port Forwarding
To change your ZyAIR’s trigger port settings, click SUA/NAT and the Trigger Port tab. The
screen appears as shown.
Note: Only one LAN computer can use a trigger port (range) at
a time