@Mihai It works!! Thank you very much.
Giovanni

@Mihai thanks for your reply, I read only today. I will try your sketch and tell you my results.

Hi,
I have same problem on arduino one clone-w5100-mysensors 1.5-sketch is the example mqtt gateway.
Can someone post a simply and working sketch of mqtt gateway??

For me the problem was the hang in setup at gw.begin call.
I solved reading this old topic : http://forum.mysensors.org/topic/773/ethernetgateway-hangs-after-gateway-startup-complete.

Hi,
I have the same problem.
I'm building a mqtt gateway with a dccduino and a ENC28J60 ethernet module, 1.6.6 Arduino IDE, 1.5 mysensors library.
I used the mysensors sketch for mqtt gateway and your sketch with the same results.
After that I tried the webserver sketch example from the arduino IDE and ... it works : I can ping the ethernert card and reach the arduino webserver.
Then my wiring is right and I think something wrong in mysensors library.