User's Manual

C HAPTER 9 | Special Application Settings
Port Triggering
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N OTE : If you set the service port of the virtual server as 80, you must set
the Web management port on System Tools –> Remote Management page
to be any other value except 80 such as 8080. Otherwise there will be a
conflict to disable the virtual server.
PORT TRIGGERING
Choose menu “Special Application->Port Triggering”, you can view and add
port triggering in the following screen. Some applications require multiple
connections, like Internet games, video conferencing, Internet calling and
so on. These applications cannot work with a pure NAT Router. Port
Triggering is used for some of these applications that can work with an NAT
Router.
Figure 66: Port Triggering
Once the Router is configured, the operation is as follows:
1. A local host makes an outgoing connection using a destination port
number defined in the Trigger Port field.
2. The Router records this connection, opens the incoming port or ports
associated with this entry in the Port Triggering table, and associates
them with the local host.
3. When necessary the external host will be able to connect to the local
host using one of the ports defined in the Incoming Ports field.
Trigger Port - The port for outgoing traffic. An outgoing connection
using this port will "Trigger" this rule.
Trigger Protocol - The protocol used for Trigger Ports, either TCP,
UDP, or All (all protocols supported by the Router).
Incoming Ports Range - The port or port range used by the remote
system when it responds to the outgoing request. A response using one
of these ports will be forwarded to the PC that triggered this rule. You
can input at most 5 groups of ports (or port section). Every group of
ports must be set apart with ",". For example, 2000-2038, 2050-2051,
2085, 3010-3030.