Question: I would like to know what the default settings for OS X are in terms of keeping the clock adjusted when I enable automatic time sync in the Date & Time preference.

I do know that the venerable `ntpd` daemon on Mavericks (10.9) and Yosemite (10.10) is no longer responsible for adjusting the time and instead a new program `pacemaker` has been introduced — so how can I know things are working or need adjustment to keep time?

Answer: 
Starting with High Sierra the ntpd system daemon was replaced with the timed system daemon which invokes /usr/libexec/timed.

The best exec I've found to get details is `systemsetup` (run as root) with its various flags:

```
[-getusingnetworktime] [-setusingnetworktime on | off]
[-getnetworktimeserver] [-setnetworktimeserver timeserver]

```

The resulting output is by far less verbose (= boring). E.g no ∂T/drift details.

Apparently *timed* uses only one ntp-server (the first one listed - checked with WireShark/LittleSnitch) even if several are entered in the system preferences/ntp.conf file.

Further reading (not very technical): [Has anyone got the time? How High Sierra has changed time synchronisation](https://eclecticlight.co/2017/10/27/has-anyone-got-the-time-how-high-sierra-has-changed-time-synchronisation/)

---

A legacy ntpd daemon is still present but unloaded. It can be loaded though by entering in Terminal.app:

```
sudo launchctl load [-F|-w] /System/Library/LaunchDaemons/org.ntp.ntpd-legacy.plist

```

in SIP disabled mode. Entering `ntpq -p` will work again then.

To load the daemon in SIP enabled mode copy the file to /Library/LaunchDaemons/:

```
sudo cp /System/Library/LaunchDaemons/org.ntp.ntpd-legacy.plist /Library/LaunchDaemons/org.ntp.ntpd.plist

```

Modify the label of the plist with nano or another editor from org.ntp.ntpd-legacy to org.ntp.ntpd:

```
sudo nano /Library/LaunchDaemons/org.ntp.ntpd.plist

```

Load the daemon:

```
sudo launchctl load -w /Library/LaunchDaemons/org.ntp.ntpd.plist

```

---

If I find a better exec to get time details with the default High Sierra daemon the answer will be updated.
To get a reliable answer on how well your clock is set, run ntpdate in debug mode:

```
ntpdate -d pool.ntp.org

```

This will gyrate for a while and end in a line such as

```
 1 Apr 17:38:16 ntpdate[4711]: adjust time server 123.45.67.89 offset 0.000810 sec

```

In this case, this meant to say my local clock was off some 810 µs (which would be spectacular, if actually true, but the value well below 100 ms does indicate a working synchronization).