Arch Linux network time setup
Turns out an NTP service exists, but isn’t enabled by default. So the fix for that is easy:
$ sudo systemctl enable systemd-timesyncd $ sudo systemctl start systemd-timesyncd
The man page explains in full:
$ man systemd-timesyncd
…
"systemd-timesyncd is a system service that may be used to synchronize the local system clock with a remote Network Time Protocol (NTP) server. It also saves the local time to disk every time the clock has been synchronized and uses this to possibly advance the system realtime clock on subsequent reboots to ensure it (roughly) monotonically advances even if the system lacks a battery-buffered RTC chip.
"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. …"
So you don’t have to reboot for the time to eventually correct itself.