[ntp:questions] Re: NTP sync on a standalone network (Windows 2k)

Richard B. Gilbert rgilbert88 at comcast.net
Thu Aug 17 01:54:38 UTC 2006

Alexandre Carrausse wrote:

> Hello,
> I want to keep the time sync'd on about 90 machines spreaded on 11 different 
> sites (one central site with the main servers and 10 remote sites with 
> secondary domain controlers and workstations).
> All the servers are W2K server and all the workstation are W2K Pro SP4.
> It is important to note that all the links between the sites are running a 
> 64 kbps, through a dedicated WAN.
> We are currently using NTP 4.1.72 which is running as a service  and has the 
> minimal configuration, ie all clients getting their time from the "main 
> central server". The server is getting its time from itself, ie
> But we are not sure that we are having a good "state of the art" 
> configuration and we are unsure about the time accuracy on our system.
> 1. 1st question : Is this basic configuration enough?

That is a question that only you can answer!   Does it meet your needs 
for accuracy, and tightness of synchronization?

> 2. The command line option in the service properties is greyed? Is there a 
> way to specify any options?
> 3. Any recommendations regarding the remote servers? Should we peer them 
> with the Central Site?

No.  I don't think there is any point.
> 4. Should we peer the server at the central site to keep them more on time 
> (9 minutes drift in one year, but the outside world time is not very 
> important for us)

Suit yourself.
> 5. What would happen if a silly user change the time by adding lets say one 
> hour to the main server... would this mistake be cascaded on all the system? 
> Is there any safety options? (our application would crash if the time 
> between 2 servers is more than 3 minutes)

NTPD will panic and exit if the error is more than 1024 seconds (about 
17 minutes)
> 6. I have found a  lot of litteracy on 
> http://www.eecis.udel.edu/~mills/ntp/, and nice tools on ntp.org, but where 
> can I find any specific information about the NTP 4.1.72 for W2K software? 
> What are the defaults settings compiled in this version?
> 7. What is the purpose of the ntp.drift file? What is the meaning of the 
> value contained in this file?

The drift file is used to store the current frequency correction to your 
local clock.  It is updated once per hour.  In a more "normal" 
configuration, it would help ntpd synchronize more quickly.  I wouldn't 
attempt to guess whether it would help or hurt in your configuration. 
The value is the frequency correction expressed in Parts per Million.

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