I think a fully equivalent would be to use socat On Receiving Server ssh user@proxy socat UNIX-RECVFROM:/tmp/foobar - And then on sending server ./f

I think a fully equivalent would be to use socat On Receiving Server ssh user@proxy socat UNIX-RECVFROM:/tmp/foobar - And then on sending server ./foobar | ssh user@proxy socat - UNIX-SENDTO:/tmp/foobar