NTP

It's TIME

Network Time Protocol

Network Time Protocol Daemon

Also referred to as ntpd because it's a daemon.

There's a new system called systemd-timesyncd (Is it default now on Ubuntu?) ntpd is more accurate so it's better to stick with that if you have a system that is RTOS. Timesyncd is a client-only implementation and may be more suitable for most installations.

If you don't know what time it is, then how can you run cron?! Don't let your system get out of sync.

See

• http://doc.ntp.org/4.2.6/ntpd.html?advanced=on Docs
• https://help.ubuntu.com/lts/serverguide/NTP.html
• https://wiki.archlinux.org/index.php/Network_Time_Protocol_daemon
• https://www.digitalocean.com/community/tutorials/how-to-set-up-time-synchronization-on-ubuntu-16-04
• https://www.us-cert.gov/ncas/current-activity/2017/03/22/Vulnerabilities-Identified-Network-Time-Protocol-Daemon-ntpd