Industrial access routers are used for simple and secure connections between office networks or the Internet and production networks. Routers also purposefully separate different networks so that access to the production network linked to the router is only granted to authorised users. This means that a whole connected system can be covered by a single IP address, thus considerably reducing the level of installation work involved. A VPN (virtual private network) connection can then be established between two routers via the local Internet provider. Only authorised applications are admissible.