3Com WL-603 - Manual (Page 97)

Firewall 95
Virtual Servers The Virtual servers feature allows you to route external (Internet) calls for
services such as a web server (port 80), FTP server (Port 21), or other
applications through your Router to your internal network. Since your
internal computers are protected by a firewall, machines from the
Internet cannot get to them because they cannot be 'seen'.
If you need to configure the Virtual Server function for a specific
application, you will need to contact the application vendor to find out
which port settings you need.
The maximum number of virtual servers that can be configured is 20.
Figure 72 Virtual Servers Screen
A list of popular servers has been included to choose from. Select the
server from the Popular servers drop-down menu. Then click Add, your
selection will be added to the table.
If the server that you want to use is not listed in the drop-down menu,
you can manually add the virtual server to the table. To manually
configure your virtual servers:
1 Enter the IP address, and the description in the spaces provided for the
internal machine.
2 Select the protocol type (TCP, UDP, or both TCP and UDP) from the
drop-down menu.