[ntp:questions] Remaining synced on an unsynchronised peer?

michael.buetow at comsoft.de michael.buetow at comsoft.de
Thu Dec 3 08:18:41 UTC 2009

I'll try to explain why I do not think that covers it.

In my case, the prefer peer (ntp1) is unreachable.
Even if it were never discarded (I assume that's what the immunity
idol means), my host1 and host2 should not use each other as
synchronization source.

> Mitigation Rules
> "As the selection algorithm scans the associations for selectable
>    candidates, the modem driver and local driver are segregated
>    for later, but only if not designated a prefer peer.  If so
>    designated, a driver is included among the candidate population."

Problem is, my prefer peer (to host1/host2) is neither a modem nor
local driver.
It is a genuine external source.

> "If the prefer peer is among the survivors, it becomes the system
>    peer and its clock offset and jitter are inherited by the
>    corresponding system variables. Otherwise, the combining
>    algorithm computes these variables from the survivor population."

The prefer peer indeed remains the synchronisation source, despite
being unreachable (!).
This is what I find buggy.

> The minsane Option
> "The minclock threshold

Thanks, didn't use these options before. Maybe they will become handy
at some time, but as far as I can see they will not mitigate my
immediate problem. If I cut the LANs, I expect to have no survivors.
Shouldn't my preferred peers have been eliminated as unfit due to no
reachability in ntp_proto.c:peer_unfit() (TEST13) ?

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