[ntp:questions] reach=0 and still synchronized

Miroslav Lichvar mlichvar at redhat.com
Wed May 26 09:02:29 UTC 2010

On 2010-05-25, Krejci, Pavel <pavel.krejci at siemens-enterprise.com> wrote:
> Hello,
> when my own reference clock driver (for the /dev/rtc) stops to
> respond, the ntpd still shows that the clock is synchronized:
> linux:~ # ntpq -pn
>      remote           refid      st t when poll reach   delay   offset  jitter
> *    .RTC.            6 l  260   16    0    0.000   -0.074   0.059
> The reach=0 and still the asterisk (*) is displayed at the beginning of line.

You may be hitting this bug:


It seems to happen when the reachability register wasn't full (or above
a certain limit) when the source stopped providing samples. The source
will stay marked as system peer and ntpd will continue to serve time
even if it's actually not sychronized to anything.

Miroslav Lichvar

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