[ntp:questions] What exactly does "Maximum Distance Exceded" mean?

Joseph Gwinn joegwinn at comcast.net
Fri Mar 13 16:02:34 UTC 2009

In article <49ba0e33$0$505$5a6aecb4 at news.aaisp.net.uk>,
 David Woolley <david at ex.djwhome.demon.co.uk.invalid> wrote:

> Joseph Gwinn wrote:
> > What is this error likely telling me?  What are the possibilities?  What 
> > tests will tell the tale?
> Your timeservers are unsynchronised, but for some reason not setting 
> their stratum to 16.
> Distance exceeded means that the combination of worst case round trip 
> time induced error and an assumed drift of 15ppm since the last valid 
> time on the root server (plus a few minor components) has exceeded 1 second.

How would it know of drift, in this isolated little island?

Perhaps the drift file is causing trouble.

Perhaps ntpdate was needed to get things started properly started.  

I bet the engineer did not do any of these things.  He just plugged 
thing together.  Some of the more recent loopstats and peerstats files 
have data from both timeservers, the transition being marked by a little 
cloud of 5014 status (red dots in my plots).

> It commonly happens with w32time servers that have been synchronized 
> once but left to drift.  It can also happen if the servers are orphan 
> mode, and haven't had a real time source for too long, and you are not 
> using the very latest orphan mode code.

This strengthens my impression that we don't have a clean startup, so 
clean startup will be the next thing to try.  

We were equally sloppy before, but didn't get the cloud of 9514 
complaints, probably because until now things weren't quiet enough for 
NTP to worry about the change.


Joe Gwinn

More information about the questions mailing list