[dnsdist] Burst in MaxQPSIPRule()

[Jacob Bunk Nielsen]

Hi

I've been reading up on the documentation for MaxQPSIPRule() which you 
can use to implement rate limits on DNS queries. A very nice feature.

It has a burst option which will allow clients to have bursts of 
queries, but it's not very clear to me exactly what it means. The 
documentation says:

"*burst*(/int/) – The number of burstable queries per second allowed. 
Default is same as qps"

So let's say I create a rule like:

addAction(MaxQPSIPRule(5, 32, 64, 10), DelayAction(100))

This should delay any queries that exceed 5 per second with a burst of 
10 allowed.

For how long will the client from a single IPv4 address (/32) be able to 
run 10 queries per second without being delayed? Or in other words, if 
the client issues 20 queries per second for a period, let's say 10 
seconds, for how many seconds will the client be able to get 10 queries 
per second without delay? Just 1 second?

Best regards,

Jacob

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