/DISPLAY={"network-address" | logical-name | device-name}
    Specifies a network address, logical name, or device name that
    references the X server to which the proxy server should connect.
    A network address must be in the following form:
    "[transport/][node][:]:display[.screen]"
    This option is ignored for managed proxy servers.
    The default is /DISPLAY=DECW$DISPLAY.