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

Philippe Dhont (Sea-ro) philippe.dhont at searo.be
Thu Oct 19 07:04:07 UTC 2006

Yes you can, and i finally found how.

On the server, this is my ntp.org configuration:

fudge stratum 5

I also have a second one with higher stratum.

After restarting ntpd and waiting some minutes i get this when doing a

localhost.localdomain: stratum 6, offset 0.000000, synch distance

So, basically ntp uses its local clock and then puts a stratum 6 on it.
My local clock is sync'ed with a windows2003 server like this:

Net time -S x.x.x.x set  , and put in crontab.

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

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

service timestamps debug datetime localtime
service timestamps log datetime localtime
clock timezone GMT 1
ntp server x.x.x.x               ==> this is no X ofcourse in my real
config! :)
ntp server x.x.x.x prefer
clock summer-time GMT recurring last sunday march 02:00 last sunday
october 03:00 60

Best to put 2 time servers in cisco devices.
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
*~x.x.x.x       6   373  1024  377     3.1    0.28
 ~x.x.x.x       8  1012  1024  377     2.4  -760.9
 * master (synced), # master (unsynced), + selected, - candidate, ~

(changed the x ofcourse).

So, it can be done.

-----Original Message-----
From: questions-bounces at lists.ntp.isc.org
[mailto:questions-bounces at lists.ntp.isc.org] On Behalf Of Steve Kostecke
Sent: woensdag 18 oktober 2006 14:39
To: questions at lists.ntp.isc.org
Subject: [ntp:questions] Re: How to change STRATUM on linux.

On 2006-10-18, Philippe Dhont  Sea-ro <philippe.dhont at searo.be> wrote:

> i also want to sync all my cisco switches with that ntp server but 
> that's not working and probably because the cisco switch thinks that 
> the ntp server has stratum 16 (that's what it says in show ntp 
> associations) so it thinks it is not reliable.

If your "ntp server" is reporting that it is at Stratum-16 then it is
most likely not synchronized to a time source. You need to fix this

Please post the output from 'ntpq -p your.ntp.server' and the active
lines from your ntp.conf.

> Is there a way so that i can my the cisco thinks that the linux server

> has stratum 1 so that it will take that host as reliable and configure

> its time with it ?

First you have to make sure that your "ntp server" is really working.

> in other words, how can i change on linux the stratum value ?

You can't do it directly (except in certain circumstances.

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

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