[ntp:questions] any reason why NTP client would receive -10sec diff?

David Woolley david at ex.djwhome.demon.co.uk.invalid
Tue Nov 11 07:47:34 UTC 2008

Blair Smith wrote:

+ limited time as an NTP admin!! Naturally their ntpd wasn't going to
+ accept a jump by -10sec, so subsequently their server started polled our

A normal, out of the box, ntpd would step, if all sources agreed on the 
error.  However, it is most unlikely that this is ntpd.

+ tier-one server every second for a while before giving up, after which

A real ntpd cannot be configured to poll that fast, and such a fast 
polling rate would be considered abusive.  Do you,by any chance, have 
kiss of death enabled on your server, as that polling rate would trigger 
it. I believe one of the tactics it uses to try and dissuade abusive 
clients is to report a false time to them.  A non-standard (or 
non-recent) implementation might not recognize the other signals that it 
had received the kiss.

> Their software using NTP was something called "Netware", which I'm
+ not familiar with, so I was unable to help them. One potential cause of

I didn't realise people still used this.  I thought Microsoft CIFS/SMB 
networking now completely dominated the market.  When I last encountered 
it, Netware was a file server that ran as a DOS extender; it used to be 
the dominant corporate file server software in the days of MS-DOS, and 
the early days of Windows.  Although clients can time synchronize to 
this, it is only the server that I would imagine would try to use NTP.

+ problems at our end was a lightening strike at our facility on Friday
+ 7th Nov, which affected other systems in the same building but not, as
+ far as I know, the clocks or NTP servers. The client started reporting
+ this problem on that Friday evening, but that could be just a coincidence.

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