[ntp:questions] negative estbdelay?

Danny Mayer mayer at ntp.isc.org
Tue Oct 23 16:43:22 UTC 2007

Dave Johnson wrote:
> Just ran into a system that has a estbdelay of -2.6 seconds.  Needless
> to say this is causing the system to run 2.6 seconds behind, but at
> the right rate.
> It is configured as a broadcastclient.  There is one stratum 1 system
> braodcasting on the subnet for which this client should sync to.
> Something must have gone very wrong when this client tried to
> calculate the delay when it started up.
> Should the system ever try to re-calibrate the broadcast delay once
> running or will it stay the same as long as the broadcaster keeps
> broadcasting?  Not even once a hour/day?
> It seems very wrong to accept a negative broadcast delay, shoudn't
> ntpd check for this and try again or reject the peer?
> Info below:
> version is ntpq 4.2.4p3.

If you are not using autokey authentication then it doesn't do the
autokey dance and as a result is unable to estimate the delay between
the broadcast client and the broadcast server. You didn't include the
client or server config file so it's hard to be sure.


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