Chapter 11 Network Address Translation (NAT)
NR/FWA Outdoor Series User’s Guide
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Figure 109 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 Zyxel Device to record Jane’s computer IP address. The Zyxel
Device associates Jane's computer IP address with the "open" port range of 6970 – 7170.
3 The Real Audio server responds using a port number ranging between 6970 – 7170.
4 The Zyxel Device 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 Zyxel
Device times out in 3 minutes with UDP (User Datagram Protocol) or 2 hours with TCP/IP (Transfer Control
Protocol/Internet Protocol).
Click Network Setting > NAT > Port Triggering to open the following screen. Use this screen to view your
Zyxel Device’s trigger port settings.
Note: TCP port 7547 is reserved for system use.
Note: The sum of trigger ports in all rules must be less than 1000 and every open port range
must be less than 1000. When the protocol is TCP/UDP, the ports are counted twice.