[wplug] NTP and bad time sources

[Bob Schmertz]

> -----Original Message-----
> From: Eric C. Cooper [mailto:ecc at cmu.edu]
> Sent: Friday, May 23, 2003 04:40 PM
> To: wplug at wplug.org
> Subject: Re: [wplug] NTP and bad time sources
> 
> On Fri, May 23, 2003 at 03:01:52PM +0000, Bob Schmertz wrote:
> > I'm seeing my source time get reset to wildly different times
> > (usually Jan 1, 2003) for unexplained reasons, and I'd like for my
> > Linux boxes not to swallow these changes, but to bail out.
> > 
> > If the behavior I have observed is the actual default behavior of
> > NTP, does anyone know of any way of making it do something more
> > reasonable on a wild reset of the source (hopefully without
> > modifying the source code :-))?
> 
> 1. Choose a better external source to sync with!  I've never seen a
>    stratum 3 or better host reset its time the way you describe.
> 

The setup here is that I actually have a dedicated NTP server, which ATM is not hooked up to an external source, but is freewheeling.  Things should get better when it is getting its source from a stratum 2/3 source, but suppose it loses contact with its source, and while the connection is lost, one of these time resets happens.  I'm looking into why the time reset does happen, but it seems unlikely that I can fully guarantee preventing that, so I'd like to make sure my Linux boxes don't do the wrong thing when the NTP server does.

> 2. Use "ntpdate -b ..." in your init scripts before starting ntp,
>    to set the time close enough for ntp to do its thing.
> 

I'm not sure I see how this is related to my problem.  The NTP server, the Linux boxes, and the ntpd on the Linux boxes are all starting out with good times.  It is while everything is running fine that we occasionally see the NTP server get reset, and when that happens, the Linux boxes follow suit.