[ntp:questions] Why can't clocks do inital synchronization?

Juergen Perlinger juergen.perlinger at t-online.de
Wed Jan 7 09:01:54 UTC 2009


Juergen Perlinger wrote:

> Hi everybody,
> 
> One of the things that can be annoying is that NTPD cannot do an initial
> synchronization from (most) reference clocks over a difference of more
> than 4 hours.
> 
> The reason is that 'refclock_process()' calls 'clocktime()' which in turn
> will only accept time stamps that are in a hard-coded window of +/- 4h
> around the sample time (== system time). This makes it impossible for
> systems to recover from a loss of power if there is no battery-backup
> driven hardware clock.
> 
<DISCARDED SOME TEXT>

Thanks everybody.

Seemed I made myself not totally clear: The system has NO network connection
to the outside world, but will be the time source of a little network. (NOT
internet-connected, for security reasons.) NTPDATE (which is deprecated
anyway) does not work with reference clocks, it can query servers
only. 'ntpd -g does not work, because clocks are treated different from
servers and the code of NTPD inhibits corrections of more than CLOSETIME
(4h) difference.

So basically it looks like we would have to bypass sanity checks when '-g'
is given.

I'll think about it.

-- 
juergen 'pearly' perlinger
"It's hard to make new errors!"




More information about the questions mailing list