Re: [chrony-users] chrony and ntpd xleave interoperability

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On Tue, Jan 23, 2018 at 02:44:56PM +0100, FUSTE Emmanuel wrote:
> Le 23/01/2018 à 13:00, Miroslav Lichvar a écrit :
> > With the current versions, if you can avoid the issue with
> > unsynchronized sources, they should interoperate, at least when their
> > polling intervals match. If it doesn't work for you, I'd like to see a
> > tcpdump output.
> Ok. I fixed min/max polling interval to 5 for testing purpose.
> Then I first restarted chrony. Wait for it to sync on a online source.
> Then restarted ntp and take capture.
> Will send you all the datas
> NTP is stuck in unreachable state
> Chrony is stuck with only one valid RX.

Ok. I can reproduce this problem. It seems ntpd doesn't update its
state in the interleaved mode when it receives a packet with an
unexpected origin timestamp. There was a similar issue fixed for the
basic mode few ntp releases ago:

As chronyd doesn't switch to the interleaved mode until it's receiving
valid responses and ntpd doesn't accept responses in the basic mode,
they are stuck waiting forever on each other.

A similar thing seem to happen when trying to use the interleaved mode
between two 4.2.8p10 ntpds. You said it worked for you before, so I
assume one of the ntpds was an older version which didn't have this

Miroslav Lichvar

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