[ntp:questions] ntpdate

Brad Knowles brad at shub-internet.org
Tue Jun 16 02:59:23 UTC 2009

on 6/15/09 8:52 PM, Danny Mayer quoted Scott Haneda:

>>>> I am only looking for the basics of keeping my system clock in sync on
>>>> OS X 10.5.  On OS X 10.5 the clock will drift badly on a machine that is
>>>> not logged in.  If you log in, it is less of a problem, but the date and
>>>> time parts of OS X do not check into the time servers nearly often
>>>> enough.  An idle machine is usually fine, but certain types of
>>>> applications can stall the OS, and in turn, stall the clock.  For a
>>>> server, this makes log files a royal pain to deal with timestamps.
>>> You should be running ntpd as a daemon. That will keep the clock in
>>> synch and you never have to touch it.
>> I will look at this.  It seems, OS X, in it's GUI based controls, has a
>> "use network time server", but it is known, and documented in regards to
>> OS 10.4, to not be reliable. I am not sure the position on OS 10.5,
>> which I am using, though I suspect there are still issues, as when I
>> have that setting on, I still get major drift of time.
> I don't know what OS X does, maybe Brad, our resident MAC expert, can
> tell us.

Well, I wrote the page that was originally at 
but it seems that there have been a few updates by other authors since 
then.  It does seem that Mac OS X 10.5 should be somewhat more 
intelligent about ntpd, but still not as good as it should be.  I would 
still recommend replacing the ntpd binary with one that is built from 
our sources.

You'll still have problems with the Mac OS X GUI screwing up your 
ntpd.conf file every time you go into that panel, but so long as you 
stay away from that panel then you should be able to put whatever 
appropriate stuff you might want in your ntp.conf (make sure to save a 
copy off to the side, in case you do go back to that panel), and have a 
reasonable expectation that it should work properly.  Oh, and you'll 
have to make sure that Apple doesn't "upgrade" your binary for you on 
the next OS update.

That's basically what I've done on Mac OS X ever since I ran into these 

Brad Knowles <brad at shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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