[ntp:questions] Yet Another Isolated Network Question

Bruce Baumgart bab at inel.gov
Thu Dec 16 16:59:25 UTC 2004

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.


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 

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