ZyXEL Communications VMG3926-B10A User Manual page 165

Figure 81 Trigger Port Forwarding Process: Example
Jane requests a file from the Real Audio server (port 7070).
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Port 7070 is a "trigger" port and causes the VMG to record Jane's computer IP address. The VMG
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associates Jane's computer IP address with the "open" port range of 6970-7170.
The Real Audio server responds using a port number ranging between 6970-7170.
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The VMG forwards the traffic to Jane's computer IP address.
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Only Jane can connect to the Real Audio server until the connection is closed or times out. The VMG
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times out in three minutes with UDP (User Datagram Protocol) or two 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 VMG's trigger port settings.
Figure 82 Network Setting > NAT > Port Triggering
The following table describes the labels in this screen.
Table 59 Network Setting > NAT > Port Triggering
LABEL DESCRIPTION
Add New Rule Click this to create a new rule.
# This is the index number of the entry.
Status This field displays whether the port triggering rule is active or not. A yellow bulb signifies
that this rule is active. A gray bulb signifies that this rule is not active.
Service Name This field displays the name of the service used by this rule.
WAN Interface This field shows the WAN interface through which the service is forwarded.
Trigger Start The trigger port is a port (or a range of ports) that causes (or triggers) the VMG to record
Port the IP address of the LAN computer that sent the traffic to a server on the WAN.
This is the first port number that identifies a service.
Trigger End This is the last port number that identifies a service.
Port
Trigger Proto. This is the trigger transport layer protocol.
Chapter 11 Network Address Translation (NAT)
VMG3926-B10A User's Guide
165