Two Points To Remember About Trigger Ports; Nat Advanced Screen; Figure 76 Trigger Port Forwarding Process: Example - ZyXEL Communications ZyXEL NBG334W User Manual

Figure 76 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 NBG334W to record Jane's computer IP
address. The NBG334W 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 NBG334W 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 NBG334W times out in three minutes with UDP (User Datagram Protocol), or
two hours with TCP/IP (Transfer Control Protocol/Internet Protocol).

11.5.2 Two Points To Remember About Trigger Ports

1 Trigger events only happen on data that is going coming from inside the NBG334W 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.

11.6 NAT Advanced Screen

To change your NBG334W's trigger port settings, click Network > NAT > Advanced. The
screen appears as shown.
Only one LAN computer can use a trigger port (range) at a time.
NBG334W User's Guide
Chapter 11 Network Address Translation (NAT)
135