For example, if you have an FTP server (port 21) at 192.168.123.1, a Web server (port 80) at
192.168.123.2, and a server at 192.168.123.6, you need to specify the following virtual server mapping as
shown in the table below:
Service Port Server IP Enable
21 192.168.123.1 X
80 192.168.123.2 X
1723 192.168.123.6 X
The “IP Address” section should contain the IP of the server computer in the LAN network that will be
providing the virtual services. The “Public Port” is the port number or port range on the WAN side that
will be used to access the virtual service. The “Private Port” is the port number of the service used by the
server computer. “Data Type” can be User Datagram Protocol (UDP), Transmission Control Protocol
(TCP) or both. This depends on the type of service you are running. TCP is connection-oriented protocol
and UDP is connectionless. Since most services are connection-oriented, you will most likely need to
select TCP. For example, FTP and HTTP are connection-oriented services while DNS and many
streaming radio servers are connectionless.
7.7.2 | Special Applications Some applications require multiple connections, such as Internet games, video conferencing, and
Internet telephony. These applications cannot work with a pure NAT router because of the
firewall function. However, the Special Applications feature allows some of these applications to
work with the router. Should the Special Applications feature fail to make an application work,
you can try setting your computer as a DMZ host.
Trigger: This is the outbound port number issued by the application.
Incoming Ports: When the trigger packet is detected, the inbound packets sent to specified
port numbers are allowed to pass through the firewall.
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