In home networking,
port forwarding, also called
port mapping or
punch-through, enables you to create a permanent translation entry that maps
a
protocol port on your gateway machine to an
IP
address and protocol port on your private
LAN. It's a
transparent process,
meaning network
clients cannot see that port
forwarding is being done. This process enables you to run a public Internet
service on a machine that is otherwise hidden from the Internet by your
gateway. Port forwarding may also be used to
aggregate traffic from an application that uses several ports for transactions
and consolidate it into one port for
reporting the total traffic identified with that application.
Also see
Well-Known TCP
Port Numbers in the Quick
Reference section of Webopedia.