Abstract: Methods and systems are provided for directing data packets over a network from a source machine (100) via at least one virtual packet switch (110, 130), over a physical unidirectional connection (150, 250) to at least one destination machine (200), by configuring a transmission (TX) Layer 3 agent module (140), located between the source machine and the physical unidirectional connection, to receive an Address Request Protocol (ARP) request message from the source machine and to respond with an ARP response message containing a Media Access Control (MAC) address of a reception (RX) machine, wherein the physical unidirectional connection is located on the network between the TX Layer 3 agent module and the RX machine.