ZyXEL Communications SBG5500-A, User Manual

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Chapter 8 Network Address Translation (NAT)
SBG5500 Series User’s Guide
127
Figure 97 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 SBG to record Jane’s computer IP address. The SBG
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 SBG 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 SBG
times out in three minutes with UDP (User Datagram Protocol) or two hours with TCP/IP (Transfer Control
Protocol/Internet Protocol).
Click Configuration > NAT > Port Triggering to open the following screen. Use this screen to view your
SBG’s trigger port settings.
Figure 98 Configuration > NAT > Port Triggering
The following table describes the labels in this screen.
SBG
Table 44 Network Setting > NAT > Port Triggering
LABEL DESCRIPTION
Add Click this to create a new rule.
Edit Double-click an entry or select it and click Edit to open a screen where you can modify the rule’s
settings.
Remove To remove an existing rule, select it and click Remove .
Multiple Entries
Turn On Select one or more rules and click this to enable them.
Multiple Entries
Turn Off Select one or more rules and click this to disable them.
# This is the index number of the rule.