[ntp:questions] ntpd sets clock to the year 1939

Richard B. gilbert rgilbert88 at comcast.net
Tue Mar 27 15:04:02 UTC 2007


Marc Brett wrote:
> On Mon, 26 Mar 2007 19:01:00 -0400, "Richard B. gilbert"
> <rgilbert88 at comcast.net> wrote:
> 
> 
>>Robert Dodier wrote:
>>
>>>On Mar 26, 12:50 pm, "Richard B. gilbert" <rgilber... at comcast.net>
>>>wrote:
>>>
>>>
>>>
>>>>I believe that there is a limit to the date/time range that ntpd can
>>>>handle and that it's something like 36 years.  Try setting the date
>>>>manually to something a little closer to being current.  If it's off by
>>>>less than 36 years, I think ntpd will handle it correctly.  A startup
>>>>script that set the date to a reasonable approximation; e.g. 2007 would
>>>>probably solve your problem and work for the next 36 years or so.
>>>
>>>
>>>Yes! That's it. I set the date by hand to Jan 1, 2007, and then ntpd
>>>was
>>>able to handle the rest. It seems odd to me that ntpd gets confused by
>>>too large a time difference, but oh well, it's OK the way it is.
>>>
>>>Thanks for your help,
>>>Robert Dodier
>>>
>>
>>It's hardly ever a problem since most systems have a hardware clock of 
>>some sort that can supply a reasonable starting point.  In 2007, I don't 
>>think that 1970-is a reasonable starting point.
> 
> 
> "Be liberal in what you accept, conservative in what you send."
> 
> We may not think that 1970 is a reasonable starting point, but these systems
> exist today and ntpd should deal gracefully with them.  In fact, a POSIX time of
> 0 is not exactly an unreasonable starting date for a system with no hardware
> clock and no DHCP-specified NTP server.
> 
> It's unfortunate that applications (especially an application dedicated to
> keeping the correct time, fer cryin out loud) fall over when faced with such a
> time value, but whose fault is that?
> 
> 

The opposite argument would be that it's not reasonable for ntpd to make 
a "leap of faith" and jump the time by 36 years!  Ntpd is designed to 
consider a clock that's off by 1024 seconds or more as a situation it is 
not equipped to handle.  Ntpd is behaving as it's designed and 
documented to behave.

The source is available and anyone with the necessary skills can modify 
it to handle special cases like this.  Anyone lacking the necessary 
skills can pay someone with the skills to do the work.




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