Aqualize, thanks for your useful reply. I read a bit about GET and POST. My HTML page uses POST and then the parameters are not not found in the URL but in the message body. If I want to send parameters through URL then I must use GET. In the HTML I changed the method from POST to GET and then I saw the URL http://192.168.1.200/?command=eOn, that's what I am looking for. Next step is to handle the GET request in the code in my Arduino. Thanks again.