In IT, gateway refers to the component (hardware or software) that establishes the connection between two systems. IT systems that do not know their communication partners contact their gateways directly. A gateway represents a bridge for communication between several internal or external network parts. The term gateway means that forwarded data is processed in its addressing for forwarding. This can be data in all layers of the OSI model. Depending on the layer on which the processing takes place, the corresponding system has a more specific terminology.