> The systemd-timesyncd service implements SNTP only. This minimalistic service will step the system clock for large offsets or slowly adjust it for smaller deltas. Complex use cases that require full NTP support (and where SNTP is not sufficient) are not covered by systemd-timesyncd.
SMTP is really only intended for use in edge-of-graph instances where there is no further dependence on the output e.g. a wall clock. General-purpose computers should all be using NTP.
To be precise, it's SNTP, not full-fledged NTP:
> The systemd-timesyncd service implements SNTP only. This minimalistic service will step the system clock for large offsets or slowly adjust it for smaller deltas. Complex use cases that require full NTP support (and where SNTP is not sufficient) are not covered by systemd-timesyncd.
SMTP is really only intended for use in edge-of-graph instances where there is no further dependence on the output e.g. a wall clock. General-purpose computers should all be using NTP.