5.8.5 New Port Mapping 
Port mapping is to map a port of a host on the intranet to a port of a host on the 
extranet to provide corresponding services. When a user accesses the port on the 
extranet, the server automatically maps the request to the internal machine on the 
corresponding LAN. 
Scenario: Users on the extranet cannot directly access a web server on the 
intranet. In this case, a port mapping can be created on the gateway so that the 
gateway automatically transfers the data to port 80 of the web server on the 
intranet when a user on the extranet accesses port 1000 via the cellular interface 
of the gateway.