A type of network address translation (NAT) technology that extends capabilities by translating and mapping port numbers, in addition to the IP address, when communicating with an external network.
Network Address Port Translation (NAPT), as specified in RFC 3022, is a method by which many network addresses and their TCP/UDP (Transmission Control Protocol/User Datagram Protocol) ports are translated into a single network address and its TCP/UDP ports. Together with Basic Network Address Translation (see NAT), these two operations, referred to as traditional NAT, provide a mechanism to connect a realm with private addresses to an external realm with globally unique registered addresses.