袜子 5 UDP 连接

我正在尝试连接到UDP Socks5代理，但没有服务器会回复我的初始握手。Wire shark显示正确的信号正在进入服务器，但没有收到回复

#define PUT_BYTE(ptr,data) (*(unsigned char*)ptr = data)

static int Connect_proxy(SOCKET sock,sockaddr_in Rcv_address) {
char buff[200],*ptr;
sockaddr_in SenderAddrTemp;
int SenderAddrSize= sizeof(SenderAddrTemp);
ptr=buff;
int iResult;
PUT_BYTE(ptr++,5);
PUT_BYTE(ptr++,1);
PUT_BYTE(ptr++,0);  

iResult = sendto(sock,
    buff, ptr-buff, 0, (SOCKADDR *) & Rcv_address, sizeof (Rcv_address));
if (iResult == SOCKET_ERROR) {
    wprintf(L"[Send]Conection request failed with error: %dn",      WSAGetLastError());
    //closesocket(sock);
    //WSACleanup();
    return -1;
}
iResult = recvfrom(sock,buff, 200, 0, (SOCKADDR *) & SenderAddrTemp, &SenderAddrSize);
if (iResult==-1) { 
    wprintf(L"[Recv] Connection request failed with error: %dn", WSAGetLastError());
    return -1;
}
else
    if (iResult==2)  {
        wprintf(L"OK");
    }
    return 0;

}

套接字初始化为：

    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != NO_ERROR) {
    wprintf(L"WSAStartup failed with error: %dn", iResult);
    return 1;
}
//---------------------------------------------
// Create a socket for sending data
SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (SendSocket == INVALID_SOCKET) {
    wprintf(L"socket failed with error: %ldn", WSAGetLastError());
    WSACleanup();
    return 1;
}

RecvAddr.sin_family = AF_INET;
RecvAddr.sin_port = htons(8888);
RecvAddr.sin_addr.s_addr = inet_addr("114.207.246.173");
service.sin_family = AF_INET;
service.sin_addr.s_addr = htonl(INADDR_ANY);
service.sin_port = htons(0);
bind(SendSocket, (SOCKADDR *) &service, sizeof (service));
if (iResult == SOCKET_ERROR) {
    wprintf(L"bind failed with error %un", WSAGetLastError());
    closesocket(SendSocket);
    WSACleanup();
    return 1;
}
Connect_proxy(SendSocket,RecvAddr);

谢谢！