NTP

Configuration of ntpd and timezone on >= Ubuntu 16.04

vim /etc/systemd/timesyncd.conf

  NTP=0.ca.pool.ntp.org 1.ca.pool.ntp.org 2.ca.pool.ntp.org 3.ca.pool.ntp.org
  FallbackNTP=ntp.ubuntu.com

Excute those commands :

timedatectl list-timezones
timedatectl set-timezone America/Toronto
timedatectl set-ntp on
timedatectl set-local-rtc false
timedatectl status

Old method

vim /etc/ntp.conf

  server 10.25.168.168
  server 10.25.168.169
  restrict lo
  interface ignore wildcard
  interface listen lo