ntpdate - client for setting system time from NTP servers
ntpdate-debian - set the date and time via NTP
shell> apt-get install ntpdate
shell> ntpdate -u time.apple.com
shell> ntpdate -u time.asia.apple.com
shell> ntpdate -u time.euro.apple.com
shell> ntpdate -u ntp.ubuntu.com
/etc/default/ntpdate
# The settings in this file are used by the program ntpdate-debian, but not
# by the upstream program ntpdate.
# Set to "yes" to take the server list from /etc/ntp.conf, from package ntp,
# so you only have to keep it in one place.
NTPDATE_USE_NTP_CONF=yes
# List of NTP servers to use (Separate multiple servers with spaces.)
# Not used if NTPDATE_USE_NTP_CONF is yes.
NTPSERVERS="time.asia.apple.com ntp.ubuntu.com"
# Additional options to pass to ntpdate
NTPOPTIONS=""
shell> ntpdate-debian
shell> sudo apt install ntp
shell> sudo systemctl reload ntp.service
/etc/ntp.conf
server time1.google.com iburst
server time2.google.com iburst
server time3.google.com iburst
server time4.google.com iburst
如何找到你想要連結的NTP伺服器?(此以台灣的NTP伺服器為例)
請至以下網址 http://support.ntp.org/bin/view/Servers/WebHome
Finding A Time Server→Browsing the Lists→ 選擇並點擊其一伺服器連結(此以點擊「Public NTP Pool Time Servers」為例)找到對應表中的亞洲，點擊連結「
asia.pool.ntp.org」。找到台灣的
NTP伺服器為「tw.pool.ntp.org」
driftfile /var/lib/ntp/ntp.drift
server 0.tw.pool.ntp.org
server 1.tw.pool.ntp.org
server 2.tw.pool.ntp.org
server 3.tw.pool.ntp.org
server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server 3.pool.ntp.org
server 0.asia.pool.ntp.org
server 1.asia.pool.ntp.org
server 2.asia.pool.ntp.org
server 3.asia.pool.ntp.org
server 0.europe.pool.ntp.org
server 1.europe.pool.ntp.org
server 2.europe.pool.ntp.org
server 3.europe.pool.ntp.org
server 0.ubuntu.pool.ntp.org
server 1.ubuntu.pool.ntp.org
server 2.ubuntu.pool.ntp.org
server 3.ubuntu.pool.ntp.org
server 0.amazon.pool.ntp.org iburst
server 1.amazon.pool.ntp.org iburst
server 2.amazon.pool.ntp.org iburst
server 3.amazon.pool.ntp.org iburst
shell> sudo service ntp reload
shell> ntpq -pn
shell> ntpstat
參考網站：
- https://developers.google.com/time/
- http://www.pool.ntp.org/zone/europe
- http://www.pool.ntp.org/zone/tw
- http://www.pool.ntp.org/zh/use.html
- http://support.ntp.org/bin/view/Servers/NTPPoolServers
- https://help.ubuntu.com/lts/serverguide/NTP.html
- http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/set-time.html
- https://www.asus.com/tw/support/faq/111041