The use of network technologies inside factories is nowadays classical. The IP protocol starts to replace old field buses due to its standardization, its cheap price and the large community around it. The next step will be now to use long distance IP networks to bring new opportunities to engineers as, for example, remote diagnostic and maintenance or distant learning. We concentrate our work on the safe and reliable use of long distance network such as Internet, where the quality of service (delay, bandwidth, and jitter) is not guaranteed. Introducing new network technologies, in the context of producing units of factories, will, on the one side, open new ways of working, but on the other side open new problems that have to be solved. On this paper, we will first present our statistical results that show that the web remote control is now realisable. We will then describe a proposed software architecture that includes a network sensor. The latter gives statistical and dynamical information on the network. They are used in a development methodology, design to build remote control application in a safe way, while taking into account network lack of quality of services. We will then present an application on a "web" rapid prototyping machine.