If you are running a single system or small local area network with few hosts, setting up a dedicated NTP server could be considered as an overkill. However, for a large network, setting up a private NTP server, privately serving LAN clients only is recommended.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-setup-ntp-server-and-client-on-debian-9-stretch-linux
André Verwijs
how do i set environment variables named NTPQ_* for NTP