[ntp:questions] ntpq -p command query
cswiger at mac.com
Tue Jul 30 18:15:52 UTC 2013
On Jul 30, 2013, at 7:24 AM, Biswajit Panigrahi <BP00106533 at TechMahindra.com> wrote:
> Both are communicating properly. I would like to test when the
> connectivity between those two goes down, after how much time the
> "reach" option in ntpq -p command becomes zero.
The "reach" field is a 1-byte large bitmap which tracks whether
the last 8 NTP polls got a reply, so the answer to your question is:
8 * poll interval
> The reach option will still keep on increase to 377 then gradually
> decreases to zero. The time duration to come to zero is almost 20
That seems about right if you'd just restarted both ntpds and then stopped
the server once the client got to 377, as the client wouldn't have reached
default maxpoll = 10 interval of ~17 minutes. If you'd waited longer,
it would likely take a bit over two hours to clear the reach field.
> Can we reduce the time gap ?
Yes, you can reduce maxpoll to have reach field zero out more quickly.
There are tradeoffs involved in doing so, however.
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