2020-05-03-----2022-08-12 north-america.pool.ntp.org
2021-02-20-----2022-08-01 2.us.pool.ntp.org
2020-03-11-----2022-07-15 us.pool.ntp.org
2022-01-11-----2022-01-11 1.us.pool.ntp.org
2021-02-19-----2021-12-31 0.us.pool.ntp.org
2021-12-31-----2021-12-31 3.us.pool.ntp.org
2020-07-21-----2020-07-21 0.android.pool.ntp.org
2020-06-18-----2020-06-18 3.debian.pool.ntp.org
2020-04-20-----2020-04-20 ntp.sjtu.edu.cn