阿里云：
time1.aliyun.com
time2.aliyun.com
time3.aliyun.com
time4.aliyun.com
time5.aliyun.com
time6.aliyun.com
time7.aliyun.com
windows服务器，使用time.pool.aliyun.com
其它NTP服务器：
202.108.6.95,182.92.12.11,110.75.186.248,110.75.186.247,120.25.108.11,115.28.122.198