Rawsock under Linux since the group of udp packets to send no problem, but you need to set up under the Windows ip_hdrincl options, do not add the Windows will give I add a layer of the IP header, so my IP head is equivalent to become part of the data, after added ip_hdrincl options now, sendto become very slow, do not add ip_hdrincl option sendto soon,, can you tell me what or how to solve? System is 2008 server