On 08/12/2015 16:16, Nico CARTRON wrote: 
> On 8 December 2015 at 16:07:02, Stephane Bortzmeyer (bortzmeyer@nic.fr 
> <mailto:bortzmeyer@nic.fr>) wrote: 
>> http://root-servers.org/news/events-of-20151130.txt 
> 
> Thanks Stéphane for your reactivity, as usual :) 
> 
> “Such test traffic may not be indicative of what happens to normal 
> traffic or user experience”. 
> 
> Not entirely sure what this means behind, or is it just them trying to 
> minimise the impact? 

It could be a bit of expectation management on their part. I agree with 
the statement that DNSMON and other similar tools do not provide direct 
insight into end user experience, but that is also not their goal. 
DNSMON at least is deliberately designed to measure from stable vantage 
points (RIPE Atlas anchors, formerly TTM boxes), and makes no attempt to 
simulate how recursive resolvers and end user operating systems may 
behave. In fact, it avoids such attempts, even to the point that it 
never retries a failed query, which most clients would do. I would argue 
that this is a feature of the system, providing as it does a nice clear 
signal that functions as a good metric for traffic between recursive 
resolvers and the authoritative servers. 

For reference, this is what DNSMON "saw" during the reported time 
period, which seems to correspond to the times in the report: 

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