3Com WL-550 User Manual page 76

74 C 5: C R
HAPTER ONFIGURING THE OUTER
Address Mapping
Network Address Translation (NAT) allows IP addresses used in a private
local network to be mapped to one or more addresses used in the public,
global Internet.
Figure 53 Address Mapping Screen
This feature limits the number of public IP addresses required from the ISP
and also maintains the privacy and security of the local network. We
allow one public IP address to be mapped to a pool of local addresses.
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.