[ntp:questions] Under which circumstances a reply comes 126 seconds later?
David L. Mills
mills at udel.edu
Thu Mar 6 05:01:58 UTC 2008
How true. But, are you ready for this? The minimum average headway
constraint, introduced to protect very busy servers, must be at least 16
s by default, but allow for a temporaty 8-packet burst. So, if somebody
configures a symmetric active association with iburst and autokey and
minpoll 16 (!), the server will fight back and constrain the reply rate.
I doubt anybody will ever attempt to climb that steep hill, but if so I
would like to hear what they think about it. The issues are discussed on
the rate management page in the current documentation.
Brian Utterback wrote:
> Danny Mayer wrote:
>> NTP never delays sending replies unless something is preventing it
>> from running. I have never heard of a "limited" option in ntp.conf.
>> What version of ntp are you running, on what platform, what does your
>> ntp.conf look like and what else could be prempting ntp?
> Not strictly true. The response packet for a symmetric association can
> come back an arbitrarily long time after the request was sent. The ntpd
> program does not immediately respond to symmetric packets, instead
> waiting until the peer polling interval expires.
> Brian Utterback
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