Gateway none - Manual (Page 61)

4-25
CHAPTER 4
4.3.7.3 Virtual Server
If you configure the Gateway as a virtual server, remote
users accessing services such as Web or FTP at your local
site via public IP addresses can be automatically redirected
to local servers configured with private IP addresses. In
other words, depending on the requested service (TCP/UDP
port number), the Gateway redirects the external service
request to the appropriate server (located at another internal
IP address).4.3.17 Enabling Special Applications