[ntp:questions] NTP behaviour when server is not synchronized

Geir G geir.guldstein at start.no
Fri Jun 29 18:28:27 UTC 2007

On 29 Jun, 20:07, Harlan Stenn <s... at ntp.isc.org> wrote:
> >>> In article <1183138077.657644.124... at n2g2000hse.googlegroups.com>, Geir G <geir.guldst... at start.no> writes:
> Geir> Hello, NTP configuration:
> Geir> Client: ntpd version 4... at 1.1532 running on Windows XP Servers: 2
> Geir> identical stratum 1 servers with GPS antennas directly connected
> Are these 2 servers peering with each other?  They should be.

Please note that the servers are embedded devices and (at least to my
knowledge) don't run the NTP reference implementation. I don't think
they support peering.

> Geir> I want comments on the following observations. Unfortunately, the
> Geir> system is currently not available, hence I cannot supply ntpq
> Geir> diagnostics. I know that 2 servers is the worst possible
> Geir> configuration, it is not necessary to comment that.
> Geir> For some reason one NTP server lost its GPS synch. It switched to
> Geir> internal clock started reporting stratum 12 when this happened. The
> Geir> other server was perfectly synchronized and reported stratum 1.
> Geir> Problem: ntpd rejects both servers and considers itself not
> Geir> synchronized.
> This tells me it was not peering with the other S1 server.  If it was, it
> would report S2 and follow the time of the other S1 server.

OK, you are correct.

> Geir> Questions:
> Geir> 1. Does the NTP server behave correctly when changing its stratum to
> Geir> 12? Should it perform different/other actions when it considers itself
> Geir> not synchronized?
> If it is reporting S12 then you must have it configured to use its local
> clock as a refclock.  ntpd is correctly reporting that it is sync'd to its
> local refclock.
> ntpd is behaving as designed.  It may be that your configuration is
> incorrect.

No specific configuration was done to the server to make it use its
local clock. It seems this is the the default behavior for the device.

> Geir> 2. Does ntpd behave correctly? Is a server's stratum used in any way
> Geir> in ntpd's clock selection process?
> Yes.

Is that 'Yes' to both questions?

> Have you visitedhttp://support.ntp.org/Support/ConfiguringNTP?
> H

Yes, I have. But sometimes it is more convenient to ask the experts
directly. Thank you for your answers Harlan.

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