Time services
From DWIKI
Links
Linux implementations
ntpd
ntpdate
systemd
chrony
timesyncd
FAQ
ntpdate: no servers can be used
you need to pass a server
Force IPv6 only
In ntpd.service
ExecStart=/usr/bin/ntpd -4 -g -u ntp:ntp
Or remove the 2.* lines from /etc/systemd/timesyncd.conf