[ntp:questions] Re: How to change STRATUM on linux.

Steve Kostecke kostecke at ntp.isc.org
Fri Oct 20 02:46:45 UTC 2006

On 2006-10-19, Philippe Dhont  Sea-ro <philippe.dhont at searo.be> wrote:

> Yes you can, and i finally found how.
> On the server, this is my ntp.org configuration:
> server
> fudge stratum 5
> restrict

This is the special case I mentioned previously. Refclocks (including
the often misused Undisciplined Local Clock) can be fudged to arbitrary

Most refclocks default to stratum 0. The Undisciplined Local Clock, or
LocalCLK, defaults to stratum 5; the fudge line you used is redundant
unless you are changing the stratum to something else.

> I also have a second one with higher stratum.

Second what? Where?

> After restarting ntpd and waiting some minutes i get this when doing a
> ntptrace:
> localhost.localdomain: stratum 6, offset 0.000000, synch distance
> 0.011279
> So, basically ntp uses its local clock and then puts a stratum 6 on it.

What this means is that your ntpd is following the drift of your
hardware clock.

> My local clock is sync'ed with a windows2003 server like this:
> Net time -S x.x.x.x set  , and put in crontab.

You should not be changing the clock while ntpd is running.

> My 2003 server is sync'ed with the daytime protocol to a internet time
> server.

This is probably the worst possible configuration you could have chosen.

If you must use your Windows 2003 Server as your local time source you
really should run ntpd on it. There are Windows ports of NTP linked from

> I need a good stratum value because my cisco devices (switches etc)
> will not sync if the stratum is 16.

Your ntpd was operating at stratum 16 because, in all likelyhood, it was
never synchronized to a source of time (i.e. locally attached refclock,
remote time server).

> And this works for a 100%!
> I can see in my cisco device with "show ntp associations"
> address    ref clock    st  when  poll reach  delay  offset  disp
> *~x.x.x.x   6   373  1024  377     3.1    0.28   0.3
>  ~x.x.x.x   8  1012  1024  377     2.4 -760.9  103.9

Only if you consider a 761 milliseconds, or 3/4 of a second, difference
between your time sources to be acceptable. And if you're not too
concerned with stability.

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

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