Network address translation gateway for local area networks using local ip addresses and non-translatable port addresses

A network address and gateway (20), a (10) provides the universal network is converted to the IP data unit of a network (30) occurrence of using local information IP local area network, wherein port for specific protocol housing, for example by IPSec protocol model part of ISAKMP a handshake a protocol, a tangent with the address source for service port (3-2) digital (2) and digital 3). The ISAKMP exchange the electric source computer and target computer is the same address for service (a). By providing by a fastening source address for service (a) network interface, wherein the gateway and initiate and keeps with the safety encryption transmission of IPSec protocol is using local IP address local area network Internet and server.