Your computer when it is connected to the Internet may have two IPs. One of them is for accessing your computer through the Internet. The other is for accessing your computer from the Intranet. Intranet is the network in which your computer operates. It is optional. When your computer is connected to the Internet directly through a DSL modem there is no Intranet. When there is a router between your computer and the modem and at least one other computer is connected to this router you have the Intranet. The Intranet access is for the other computer(s) connected to the router.
Whenever possible leave the default portnumber intact for both Internet and Intranet access.
