[ntp:questions] ntp orphan sync time after boot

Charles Elliott elliott.ch at comcast.net
Fri Jan 15 11:41:28 UTC 2016

I just answered a question about NTPD's broadcast mode for someone else, so
perhaps it is on my mind.  Nevertheless, it might be the answer to your
problem.  How to set it up is in confopt.html in the NTP standard
documentation, in the C:\Program Files (x86)\NTP\doc\HTML directory in the
Meinberg NTP distribution for Windows.  If you broadcast the time at the
highest rate possible, all the computers will sync as fast as possible.

You need a figure for the broadcast delay option, but this might be a way to
see if broadcast mode will work for you.  For a few days, make, using the
"week" option, the loopstats file on each computer.  Then pull several in to
Excel or another spreadsheet program.  Compute the average and the standard
deviation of the delay column; half the delay is the packet flight time
between computers.  If the ratio of the StdDev/Average is "small" on each
computer, then the computers are more likely to be closely synched.  You
could also plot the delay against the time in the second column on the left
to see if it is a nice, straight line.

As an aside, you might consider the wisdom of shutting down each computer
each night, for energy savings I suppose, versus the wear and tear of
starting up delicate electronics each morning.  The new motherboards and
CPUs from Supermicro and Intel use a small fraction of the wattage of their

Charles Elliott

-----Original Message-----
From: questions
[mailto:questions-bounces+elliott.ch=comcast.net at lists.ntp.org] On Behalf Of
Rini van Zetten
Sent: Thursday, January 14, 2016 9:26 AM
To: questions at lists.ntp.org
Subject: [ntp:questions] ntp orphan sync time after boot


We have several devices connected to each other without internet connection.
They have to be synchronised, but the absolute time is not important.
I have set up the ntpd on each device in orphan mode with one device as
This works fine.

The problem we have is that it takes about 5 minutes after boot before the
devices are synchronised.
Is there anything possible to speed up this process ?



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