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Chapter 11 Network Address Translation (NAT)
VMG5313-B10A/-B30A Series User’s Guide
187
11.4 The Port Triggering Screen
Some services use a dedicated range of ports on the client side and a dedicated range of ports on
the server side. With regular port forwarding you set a forwarding port in NAT to forward a service
(coming in from the server on the 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 VMG 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
VMG's WAN port receives a response with a specific port number and protocol ("open" port), the
VMG 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.
For example:
Figure 78
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 VMG to record Jane’s computer IP address. The VMG
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 VMG 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 VMG
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.
Содержание VMG5313-B10A
Страница 15: ...15 PART I User s Guide ...
Страница 16: ...16 ...
Страница 32: ...Chapter 2 The Web Configurator VMG5313 B10A B30A Series User s Guide 32 ...
Страница 40: ...Chapter 4 Tutorials VMG5313 B10A B30A Series User s Guide 40 ...
Страница 71: ...71 PART II Technical Reference ...
Страница 72: ...72 ...
Страница 78: ...Chapter 5 Network Map and Status Screens VMG5313 B10A B30A Series User s Guide 78 ...
Страница 106: ...Chapter 6 Broadband VMG5313 B10A B30A Series User s Guide 106 ...
Страница 162: ...Chapter 9 Routing VMG5313 B10A B30A Series User s Guide 162 ...
Страница 180: ...Chapter 10 Quality of Service QoS VMG5313 B10A B30A Series User s Guide 180 ...
Страница 198: ...Chapter 11 Network Address Translation NAT VMG5313 B10A B30A Series User s Guide 198 ...
Страница 210: ...Chapter 14 Interface Group VMG5313 B10A B30A Series User s Guide 210 ...
Страница 218: ...Chapter 15 USB Service VMG5313 B10A B30A Series User s Guide 218 ...
Страница 232: ...Chapter 17 Firewall VMG5313 B10A B30A Series User s Guide 232 ...
Страница 240: ...Chapter 19 Parental Control VMG5313 B10A B30A Series User s Guide 240 ...
Страница 250: ...Chapter 21 Certificates VMG5313 B10A B30A Series User s Guide 250 ...
Страница 296: ...Chapter 23 Voice VMG5313 B10A B30A Series User s Guide 296 ...
Страница 300: ...Chapter 24 Log VMG5313 B10A B30A Series User s Guide 300 ...
Страница 308: ...Chapter 27 xDSL Statistics VMG5313 B10A B30A Series User s Guide 308 ...
Страница 318: ...Chapter 30 Remote Management VMG5313 B10A B30A Series User s Guide 318 ...
Страница 322: ...Chapter 32 TR 064 VMG5313 B10A B30A Series User s Guide 322 ...
Страница 332: ...Chapter 36 Log Setting VMG5313 B10A B30A Series User s Guide 332 ...
Страница 335: ...Chapter 37 Firmware Upgrade VMG5313 B10A B30A Series User s Guide 335 Figure 176 Error Message ...
Страница 336: ...Chapter 37 Firmware Upgrade VMG5313 B10A B30A Series User s Guide 336 ...
Страница 352: ...Chapter 40 Troubleshooting VMG5313 B10A B30A Series User s Guide 352 ...
Страница 353: ...353 PART III Appendices Appendices contain general information Some information may not apply to your device ...
Страница 354: ...354 ...
Страница 374: ...Appendix B Wireless LANs VMG5313 B10A B30A Series User s Guide 374 ...
Страница 390: ...Appendix E Legal Information VMG5313 B10A B30A Series User s Guide 390 ...