[ntp:questions] NTP request retry?

Rob nomail at example.com
Mon Jan 27 18:10:32 UTC 2014

Marco Marongiu <brontolinux at gmail.com> wrote:
> On 01/26/2014 08:08 PM, Rob wrote:
>> My hypothesis is that the ARP entry for the NTP server has timed out,
>> and when ARP has to resolve an entry in some implementations the first
>> packet is always lost (it is not cached pending a reply).
>> When the cycle is 1024 seconds, the ARP entry has again timed out the
>> next poll cycle and the issue is the same.
> If you believe that it is the problem, and you own the servers you're
> polling, then you may set maxpoll so that the polling interval is always
> smaller then the ARP cache timeout.

Despite lots of tracing I still cannot really pinpoint the problem.

The only thing I see is that ping has absolutely zero loss and all
usual protocols work fine, but ntp indicates a high loss when there
is no other network activity.

When the network is kept busy, ntp works fine as well.
Very strange.

However, I do not like to "fix" it by increasing frequency, it may
not even help.  I'd like to have some "burst until there is a reply,
up to X tries" option.
It appears to be a function of other NTP clients, but not of ntpd.

More information about the questions mailing list