[ntp:questions] Re: Yet Another Isolated Network Question

m.marien mmATRiverCityCanadaDOTcom
Thu Dec 16 23:23:54 UTC 2004

"Bruce Baumgart" <bab at inel.gov> wrote in message 
news:Xns95C16598DC25baumgabainelgov at
>I have been following the isolated network configuration discussions
> because I am in a very similar situation.
> I need to sync our end of a widespread, but limited number of
> connections, private network.  First, a few interjections of reality.
> 1) It will remain completely, totally private.  No outside connections,
> no matter how brief.  Never.
> 2) I cannot simply add a GPS/WWVB/etc reciever.  End of discussion.
> 3) I cannot alter connection methods, topology, etc.
> 4) I am not interested in sub-second synchronization.  When I got brought
> in, the DNS server and the SMTP server were 1/2 an hour apart, and had
> been that way for a long time.  +/- a few seconds is fine <shudder>.
> There is one NTP server on the network.
> My thoughts are to set up a local server, with a server statement
> pointing to the remote server and one for my local clock.  I would advise
> people to point their local machines to that one local server.
> If I lose my connection to the psuedo-outside world or that server, I
> still want to be able to keep my local machines together, hence the local
> clock thing.  The room is (mostly, usually) climate controlled, so what I
> am hoping is that after the local server talks to the remote server for
> awhile, it will have it's frequency adjusted and a proper value set in
> the drift file.  That way, if my external link goes down, the local
> server won't drift too far (hopefully) by the time things get restored.
> The clients are mostly, if not completely, Windows-flavored things.  I
> have to assume that they would sync to me by SNTP.  I have no visibility
> to them.
> Questions
> Will NTP work the way I think it will in these circumstances?  Mainly
> thinking about the local server serving time, not drifting too far, etc?
> Is there a better way, given my loose requirements and draconian
> restraints?

If the systems are window flavoured and Win2000 or better, they will all 
sync to the DC at the root of the tree. If you don't have AD or an NT 
domain, you can make the Win2000 or better sync to a source with the 

C:\>net time /setsntp:time.server.name or IP address.

It's simple enough to have the Linux or Unix systems run NTP and sync to the 
one NTP server.

You may not have accurate time, but all the systems will have the same time. 

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