Chapter 9 Network Address Translation (NAT)
P-320W v3 User’s Guide
95
WAN) to the IP address of a computer on the client side (LAN). The problem is
that port forwarding only forwards a service to a single LAN IP address. In order to
use the same service on a different LAN computer, you have to manually replace
the LAN computer's IP address in the forwarding port with another LAN
computer's IP address.
Trigger port forwarding solves this problem by allowing computers on the LAN to
dynamically take turns using the service. The P-320W v3 records the IP address of
a LAN computer that sends traffic to the WAN to request a service with a specific
port number and protocol (a "trigger" port). When the P-320W v3's WAN port
receives a response with a specific port number and protocol ("incoming" port),
the P-320W v3 forwards the traffic to the LAN IP address of the computer that
sent the request. After that computer’s connection for that service closes, another
computer on the LAN can use the service in the same manner. This way you do not
need to configure a new IP address each time you want a different LAN computer
to use the application.
9.3.2.1 Trigger Port Forwarding Example
The following is an example of trigger port forwarding.
Figure 60
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 P-320W v3 to record Jane’s computer
IP address. The P-320W v3 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 P-320W v3 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 P-320W v3 times out in three minutes with UDP (User Datagram
Protocol), or two hours with TCP/IP (Transfer Control Protocol/Internet Protocol).
Internet
Jane’s computer
Real Audio Server
Port 7070
Summary of Contents for P-320W v3
Page 2: ......
Page 8: ...Safety Warnings P 320W v3 User s Guide 8 ...
Page 10: ...Contents Overview P 320W v3 User s Guide 10 ...
Page 18: ...Table of Contents P 320W v3 User s Guide 18 ...
Page 20: ...20 ...
Page 24: ...Chapter 1 Getting to Know Your P 320W v3 P 320W v3 User s Guide 24 ...
Page 36: ...Chapter 2 Introducing the Web Configurator P 320W v3 User s Guide 36 ...
Page 54: ...54 ...
Page 72: ...Chapter 4 Wireless LAN P 320W v3 User s Guide 72 ...
Page 76: ...Chapter 5 Wireless Client Mode P 320W v3 User s Guide 76 ...
Page 88: ...Chapter 7 LAN P 320W v3 User s Guide 88 ...
Page 104: ...Chapter 10 VLAN P 320W v3 User s Guide 104 ...
Page 105: ...105 PART III Security Firewall 117 Content Filtering 125 ...
Page 106: ...106 ...
Page 116: ...Chapter 11 WAN P 320W v3 User s Guide 116 ...
Page 124: ...Chapter 12 Firewall P 320W v3 User s Guide 124 ...
Page 130: ...130 ...
Page 134: ...Chapter 14 Static Route P 320W v3 User s Guide 134 ...
Page 140: ...Chapter 15 Remote Management P 320W v3 User s Guide 140 ...
Page 154: ...Chapter 16 Universal Plug and Play UPnP P 320W v3 User s Guide 154 ...
Page 155: ...155 PART V Maintenance and Troubleshooting System 157 Logs 163 Product Specifications 193 ...
Page 156: ...156 ...
Page 178: ...Chapter 18 Logs P 320W v3 User s Guide 178 ...
Page 184: ...Chapter 19 Tools P 320W v3 User s Guide 184 ...
Page 192: ...Chapter 20 Troubleshooting P 320W v3 User s Guide 192 ...
Page 196: ...Chapter 21 Product Specifications P 320W v3 User s Guide 196 ...
Page 198: ...198 ...
Page 260: ...Index P 320W v3 User s Guide 260 ...
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