[ntp:questions] High-precision synchronization between two computers

Steve Kostecke kostecke at ntp.org
Wed Aug 29 19:13:36 UTC 2007

On 2007-08-28, Bruno.OBSOMER at thalesaleniaspace.com wrote:

> For a little project, I have two computers which need to be as best 
> synchronized as they could be. I tried to use ntp for that. I defined the 
> first one as a time server. The second one use the first one as unique 
> time server (I know that several time servers is recommended, but I don't 
> need perfect time, only perfect synchronization).

If you want "perfect synchronization" then you want your server to be
synchronized to a high quality time base (e.g UTC acquired via GPS) so
that the clients will not be chasing a moving target.

> When I run ntpdate on the client, all work fery well. To achieve best 
> synchronization, I run it several time and it gives me precision      
> up to 0.000001 seconds (which is very very well). The problem is      
> that I don't want to run ntpdate from a cron job since I cannot have  
> any steps (unless at run time). So I use ntpd, but it seems not to    
> work since the difference between the two clocks becomes bigger and   
> bigger.                                                               

There are a number of possible issues here. Please post the ntp.conf
files from both systems omitting the comment lines.

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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