Now the problem is very strange, look, have the idea,
My computer can't receive udp multicast data, but the sender really to send over there, a variety of Settings and there is no problem, my Internet cable connects to another computer under the Windows (the IP and Mac address to me), can receive the data,
Then the code is no problem, the code in the same network segment on another computer Debian works well, can receive data,
At the same time, tried to use the same network segment of another computer send a udp data to me, I can receive, I pure amateur, hope bosses give advice or comments,