Подключение к серверам NTP

#define _CRT_SECURE_NO_WARNINGS
#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <iostream>
#include <winsock2.h>
#include <ctime>
 
#pragma comment(lib, "ws2_32.lib")
 
void ntpdate()
{
    int portno = 123;
    const int maxlen = 1024;
    int i;
    unsigned char msg[48] = { 010,0,0,0,0,0,0,0,0 };
    unsigned long buf[maxlen];
    struct protoent *proto;
    struct sockaddr_in server_addr;
    int s; 
    long tmit; 
    proto = getprotobyname("udp");
    s = socket(PF_INET, SOCK_DGRAM, proto->p_proto);
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr("23.101.187.68");
    server_addr.sin_port = htons(portno);
    i = sendto(s, (const char*)msg, sizeof(msg), 0, (struct sockaddr *)&server_addr, sizeof(server_addr));
    struct sockaddr saddr;
    int fromlen = sizeof(saddr);
    i = recvfrom(s, (char*)buf, 48, 0, &saddr, &fromlen);
    tmit = ntohl((time_t)buf[4]); //# get transmit time
    tmit -= 2208988800U;
    std::cout << "NTP time is " << ctime((const time_t *)tmit) << std::endl;
    i = time(0);
    std::cout << "System time is " << (i - tmit) << " seconds off" << std::endl;
}
int main() {
 
    WSADATA wsaData;
    if (!WSAStartup(MAKEWORD(2, 2), &wsaData))
        ntpdate();
    return 0;
}