How to tell when time has been sync'ed with NTP server in Mac OS X Lion?

Question

I know that a similar question has been asked at superuser.

But I tried to grep for "time reset" in my /var/log/system.log and I can't find any instance of it. In fact, I even searched in the eight archived copies of system.log (system.log.0.bz2 through system.log.7.bz2). All I found when grep'ing for the word "ntpd" are lines like these:

Feb 20 10:17:16 caspar ntpd[44498]: proto: precision = 1.000 usec
Feb 20 12:27:21 caspar ntpd[44625]: proto: precision = 1.000 usec
Feb 20 18:31:53 caspar ntpd[44625]: bind(28) AF_INET6 > <censored IPv6> flags 0x11 failed: Can't assign requested address
Feb 20 18:31:53 caspar ntpd[44625]: unable to create socket on en0 (7) for <censored IPv6>

Update #1

Following @Raolin's suggestion, I now see lines like this in /tmp/ntpd.log:

21 Feb 19:30:52 ntpd[2328]: DNS time.asia.apple.com. ttl 1900
21 Feb 19:30:52 ntpd[2328]: DNS time.asia.apple.com. minpoll 9
21 Feb 19:30:52 ntpd[2328]: DNS time.asia.apple.com. maxpoll 12
21 Feb 19:30:52 ntpd[2328]: DNS time.asia.apple.com. +iburst
21 Feb 20:02:32 ntpd[2328]: DNS time.asia.apple.com. ttl 4013
21 Feb 21:09:24 ntpd[2328]: DNS time.asia.apple.com. ttl 3507

I'm not sure if the lines containing 'ttl' means it's trying to sync.

Answer 1

I'm not sure if there are any log messages by default—I couldn't find any either.

One possible solution is to just enable logging. You can edit:

/usr/libexec/ntpd-wrapper

And add this (or something similar):

-l /tmp/ntpd.log

To the exec /usr/sbin/ntpd line in the script (the last line). Then kill the ntpd process (it will automatically relaunch) or reboot.

The resulting log looks something like this:

ntpd[10728]: ntpd [email protected] Fri Feb  5 17:38:17 UTC 2016 (124~824): Starting
ntpd[10728]: Command line: /usr/sbin/ntpd -c /private/etc/ntp-restrict.conf -n -g -p /var/run/ntpd.pid -f /var/db/ntp.drift -l /tmp/ntpd.log
ntpd[10728]: proto: precision = 1.000 usec (-20)
ntpd[10728]: proto: fuzz beneath 0.083 usec
ntpd[10728]: Listen and drop on 0 v6wildcard [::]:123
...
ntpd[10728]: drift PPM:0.000 -> -37.418
ntpd[10728]: peer time.asia.apple.com. @ 17.253.66.125
ntpd[10728]: sample offset +0.000000 s @ 17.253.66.125
ntpd[10728]: sample offset -0.000569 s @ 17.253.66.125
ntpd[10728]: sample offset -0.000518 s @ 17.253.66.125