网络时间协议 --- 网络对时程序

// TCPIP time protocol.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
 #include <winsock2.h>
 #include <stdio.h>
 #pragma comment(lib,"WS2_32")
 class CInitSock
 {
 public:
     CInitSock(BYTE minorVer=2,BYTE majorVer=2)
     {
         WSADATA wsaData;
         WORD sockVersion = MAKEWORD(minorVer,majorVer);
         if(::WSAStartup(sockVersion,&wsaData)!=0)
         {
             exit(0);
         }
     }
     ~CInitSock()
     {
         ::WSACleanup();
     }
 };
CInitSock initSock;
void SetTimeFromTP(ULONG ulTime)
{
    FILETIME ft;
    SYSTEMTIME st;
    st.wYear = 1900;
    st.wMonth = 1;
    st.wDay = 1;
    st.wHour = 0;
    st.wMinute = 0;
    st.wSecond = 0;
    st.wMilliseconds = 0;
    SystemTimeToFileTime(&st,&ft);

    LONGLONG *pLLong=(LONGLONG*)&ft;
    *pLLong +=(LONGLONG)10000000*ulTime;
    FileTimeToSystemTime(&ft,&st);
    SetSystemTime(&st);
}
int main()
{
    SOCKET s = ::socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(s == INVALID_SOCKET)
    {
        printf("Failed socket()\n");
        return 0;
    }
    sockaddr_in servAddr;
    servAddr.sin_family = AF_INET;
    servAddr.sin_port = htons(37);

    servAddr.sin_addr.S_un.S_addr = inet_addr("18.145.0.30");
    if(::connect(s,(sockaddr*)&servAddr,sizeof(servAddr)) == -1)
    {
        printf("Failed connect()\n");
        return 0;
    }

    ULONG ulTime = 0;
    int nRecv = ::recv(s,(char*)&ulTime,sizeof(ulTime),0);
    if(nRecv>0)
    {
        ulTime=ntohl(ulTime);
        SetTimeFromTP(ulTime);
        printf("成功与时间服务器的时间同步！\n");
    }
    else
    {
        printf("时间服务器不能确定当前时间!\n");
    }
    ::closesocket(s);
    return 0;
}

试了好多服务器IP地址，都不好使.....郁闷....