ZyXEL Communications NBG6616 - Two Points to Remember about Trigger Ports

Chapter 14 NAT
NBG6616 User’s Guide
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2 Port 7070 is a “trigger” port and causes the NBG6616 to record Jane’s computer IP address. The
NBG6616 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 NBG6616 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
NBG6616 times out in three minutes with UDP (User Datagram Protocol), or two hours with TCP/IP
(Transfer Control Protocol/Internet Protocol).
14.5.5 Two Points To Remember About Trigger Ports
1 Trigger events only happen on data that is coming from inside the NBG6616 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.