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Re: [DNSOP] Measuring DNS TTL clamping in the wild

Mikael Abrahamsson <swmike@swm.pp.se> Sat, 02 December 2017 10:29 UTC

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Date: Sat, 02 Dec 2017 11:29:35 +0100
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Steve Crocker <steve@shinkuro.com>
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Subject: Re: [DNSOP] Measuring DNS TTL clamping in the wild
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On Fri, 1 Dec 2017, Steve Crocker wrote:

> Let me make a guess that the only lengthening that takes place in 
> practice is a floor of ten seconds.
>
> Comments?

I might be misinterpreting, but from the data presented in the graph in 
section 3.2 it looks like some will increase TTL to 7200 seconds at the 
highest. There seems to be large bumps at the 600, 1200 and 1800 second 
"minimum TTL" capping (if I guess correctly from looking at that graph).

It would be interesting to hear what problems these operators are trying 
to solve by implementing these minimums. 7200 seconds does seem like a 
pretty high value to lower bound TTLs at.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se

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