I'm having the same problem too. I'm trying to make sure that the tcpsocket uses my wireless connection by setting the setLocalAddress() with my wireless ip and still it sends by the ethernet connection... If i disconnect the ehternet connection it sends on wireless...

I had to change the function setLocalAddress() in QAbstractSocket.h from protected to public otherwise using QTcpSocket wouldn't let me use the protected function, as it is not declared on QTcpSocket...

Have you found a solution to this problem?