Zoom X4 - Manual (Page 23)

Chapter 2: Advanced Setup Options 23
2.5 Virtual Server
To use certain special applications—some Internet games,
videoconferencing, and Internet telephony, for example—you may
have to use nonstandard ports. A port is an endpoint to a logical
connection. The port number identifies the logical channel being
used—for instance, port 21 is associated with FTP (File Transport
Protocol). If you want to use an application that requires access to
a port that the X4 would normally deny, you have to modify the
X4’s settings to accommodate it.
One way to do this is to implement a virtual server. In other cases,
you might want to have multiple ports open and for this you need
to set up a Demilitarized Zone (DMZ); see page 26 for instructions
on configuring a DMZ.
Tip:We recommend that you visit this web site:
www.practicallynetworked.com/sharing/specialapps.htm .
This site contains easy-to-understand instructions about
opening ports and accommodating special applications.
To set up a virtual server, from the Advanced Setup page, click
the Virtual Server button.