It seems that the NETMF does not accept Multicast on RAW Sockets in contrast to the big .NET framework.
Anyone knows how to retrieve a remote endpoint. IP and port number on Dgram sockets, or to make a RAW socket accepting multicast? Maybe through IOCTL?
UPDATE: Found the solution for Dgram sockets
var buf = new byte[socket.Available];
EndPoint remoteEndpoint = new IPEndPoint(IPAddress.Any, 0);
The endpoint is populated after the ReceiveFrom :-[