Figure 208 Trigger Port Forwarding Process: Example; Figure 209 Advanced > Nat > Port Triggering - ZyXEL Communications ZYWALL 2 PLUS User Manual

Chapter 17 Network Address Translation (NAT)

Figure 208 Trigger Port Forwarding Process: Example

1 Jane (A) requests a file from the Real Audio server (port 7070).
2 Port 7070 is a "trigger" port and causes the ZyWALL to record Jane's computer IP
address. The ZyWALL 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 ZyWALL 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 ZyWALL times out in three minutes with UDP (User Datagram Protocol) or
two hours with TCP/IP (Transfer Control Protocol/Internet Protocol).
Click ADVANCED > NAT > Port Triggering to open the following screen. Use this screen
to change your ZyWALL's trigger port settings.
Figure 209 ADVANCED > NAT > Port Triggering
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