Qt version 4.8, use QUdpSocket join multicast fetching multiple multicast data, in A single network card situation without any problems, but into the multiple network card on the machine, no matter in which the data on the card will be taken less than sowing multiple groups of data, A former data using the network card, the card B restart, the number of normal, whereas the same, you just need to restart A, do not need to reboot every time, ah ~ ~ ~ ~ ~ ~ how to solve