PSTfile is a system which allows the exchange of files between two TCP/IP networks with different classification levels or security policies which would impede their connection through any other means. The two networks are not equivalent: one is considered to have a higher classification degree or security level.

PSTfile guarantees the impossibility of any type of traffic between the two networks except the files transferred by the system itself.

PSTfile has been developed to work in MAXIMUM security environments where networks of different security levels or classification must be kept separated. It is appropriate for fulfilling the most stringent security requirements, for example, when the protocol stack must be discontinued at all OSI model levels and where information flow between two networks must be controlled.

PSTfile establishes mapping between source and destination folders. The Gateway moves the files found in the source to the target.