Procedure and configuration in order to transmit data

Method of transmitting data for operating and observing an automation system embedded in a first internal network protected by a first firewall from a remote client embedded in a second internal network independent from the first internal network, without the authorization to pass the firewall, via the World Wide Web of the Internet using the Hypertext Transfer Protocol (HTTP), comprising the steps of:

• a) the automation system sends a first connection request by means of a HTTP command to a central web server located in the World Wide Web outside the area protected by the first firewall, whereby the first connection request cannot be distinguished by the first firewall from a regular web browser access;
• b) the connection request is kept open thereby generating a data transfer tunnel between the automation system and the central web server;
• c) the remote client sends at least one second connection request by means of a HTTP command to the central web server in the World Wide Web;
• and
• d) the data transfer tunnel between the automation system and the web server is used to establish a contact for bi-directionally sending and receiving reference data;
• whereby no Internet Protocol (IP) address of the automation system has to be known to the World Wide Web.