Network Time

S

sjsadler

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I note that when my dual G4 Mac has been on for a while the time starts to drift out of sync with the Solaris machines on the network (all of which are synchronised). If I press the "synchronise now" but in the "Network Time" pane of the "Date and Time" control panel everything goes back into synch.

It would appear that the time is only automatically reset on startup and since (the Mac is now a stable UNIX box) I would rather not restart it on a regular basis I was wondering if there was a way to get it to synchronise automatically and on a regular basis.
 
If you click "Use a network time server" in the Date & time preference pane (Network Time tab), your computer should sync regularly, not just at startup. Mine, for example, polls the time server about every 2 hours.
 
Thanks for the reply, this raises a couple more questions.

(1) How can you tell when a synchronisation can occured?

(2) Is there anyway to up the rate at which the synchronisation occurs (as there is the possibility that our local time reference could be noisy)?
 
Originally posted by sjsadler
(1) How can you tell when a synchronisation can occured?
Click to expand...
In my case, I had to open up the port in my firewall (BrickHouse; just a front-end for the Mac OS X firewall) a long time ago. That's how I figured out the port and how frequently it connected. Any utility that monitors your connection could give you the port number and the time of connection. But it was about every hour or so, IIRC. And the first check always occurs right after bootup and login.

Originally posted by sjsadler
(2) Is there anyway to up the rate at which the synchronisation occurs (as there is the possibility that our local time reference could be noisy)?
Click to expand...
IMHO, the once-hourly check is pretty aggressive, since your clock isn't going to drift much over the course of a few hours. I'd just try it and see if it works for you. :D

-- Steve
 
Originally posted by sjsadler
How can you tell when a synchronisation can occured?
Click to expand...

When synchronization occurs, a line will be written to your console log. Here is a line from my log showing the sync:

29 Jul 19:14:24 ntpdate[16331]: step time server 17.254.0.26 offset -15.239793 sec

Chris
 
My console.log doesn't report any updates (at least in the last 24 hours) until I manually use the set network time. Netinfo tells me that ntp's port is 123. The ntpd process has been running since I last restarted.

I don't believe that I have changed anything for ntp since installation.

Stewart
==
 
Apparently ntpd takes two arguments minpoll and maxpoll, specifying the maximum and minimum time between polls (or the log base 2 of the time).

On my machine it appears that the settings are in /etc/ntp.conf (there are equivalent values in the netinfo /config/ntp but these are ignored).

There is a useful tool ntpdc for monitoring the ntpd daemon.

However, there are no man pages for ntp, ntpd or ntpdc on the mac - had to look them up elsewhere.
 
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