[ntp:questions] what happens if ntp server jumps time BIG TIME

unruh unruh at invalid.ca
Sat Feb 11 01:03:52 UTC 2012

On 2012-02-09, bombjack <bombjack99 at gmail.com> wrote:
> Hi,
> Scenario:
> - I'm in control of a NTP server and can change the time on this
> server as I please (this server is "sync'ed to the hw-clock)
> - I have a client that is sync'ed with the server above (and only that
> server)
> What happens if I change the time on the server, lets say 5 years
> forward? Will the client sync to the server? and If so, how? big leap?
> small steps? Will the flag "-g" affect how the client reacts to this
> changes?

No. If ntp finds the time out by >128ms, it steps the clock. If it finds
it out by 1000(?) sec it says "Something is horribly wrong here" and
abandons ship. (ntpd exits).

> Yes, I do realise that this scenario is stupid in many ways. Only one
> server, big time changes on the server etc etc, and I do know how to
> fix ti, but this is the scenario that I need an answer to.
> Any input welcome!
> BR,
> Fredrik

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