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Re: How can I get ntp working?



On Wednesday 17 October 2001 14:13, Dave Sherohman spewed forth:
> On Wed, Oct 17, 2001 at 10:44:50PM +0530, Raghavendra Bhat wrote:
> > [Wed, Oct 17, 2001 at 09:36:38AM -0500] Dave Sherohman :
> > > ntpdate sets the time to be correct now.
> >
> > ntpdate sets  the system time after  syncing with the  time server.  Now
> > you have to update the hardware clock by doing a 'hwclock -w' before you
> > do a reboot/halt.  Have I gone wrong somewhere ?
>
> Slightly.  Unlike date/rdate, it appears that ntpdate also updates
> the hardware clock, so you don't need to use hwclock if you use
> ntpdate.
>
> > > idea is that you run ntpdate  at boot (or on installation) to make the
> > > time correct, then run ntpd continuously to keep it correct.
> >
> > Do we have  ntpdate symlinked in all run-levels ?
>
> It should be set up to run in all networked runlevels (2-5) by the
> package's installer.
>
> > You  mean to say that
> > ntpdate should run before ntp ?
>
> Yes.  ntpdate cannot run while ntpd is active because they both
> listen on the same port.  The debian ntpdate and ntp packages handle
> this properly, by setting up the rc?.d symlinks such that ntpdate
> runs first, then ntpd is started.
>
> > Do ntpdate and ntp read the same config
> > file ie. /etc/ntp.conf ?
>
> No.  ntpdate isn't that smart and needs to have its list of time
> sources passed on the command line.  To configure it, you have to
> edit /etc/init.d/ntpdate and follow the instructions in the script's
> comments.


Additional comment.
ntpd on Server 'A' will not accept any time synchronization requests until it 
is satisfied it's got a reasonable time, then Computer 'B' will be able to 
synchronize with Server 'A'.
After you run ntpdate and start ntpd -- wait a little while.  If you need to 
know exactly how long - watch tcpdump for the ntp traffic to die down a 
little bit and then try it.
I find 10 minutes is a very good number.



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