Method for operating a network (10), wherein the network (10) comprises at least one outer network (12) having at least one network device (14) and at least one inner network (13) having at least one network device (15), wherein additionally a transmission unit (16) is present that blocks a transmission of data from the outer network (12) to the inner network (13) and allows it in the opposite direction (or vice versa), characterised in that the transmission unit (16) permits a transmission of data only from the inner network (13) to the outer network (12) and the at least one network device (15) sends data from the inner network (13) to the transmission unit (16) with a first address, wherein the transmission unit (16) converts this first address into a second address and thereafter the data are transmitted with this second address in the direction of the outer network (12), the second address being a target address for the at least one network device in the outer network (12).