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

I strongly disagree with your "terminology", TTL is a hint about maximum
caching period, not a demand or a contract.
A resolver can at any time for any reason discard cached entries.
Many Authoritative operators have "unreasonable" TTL's like less than 10
seconds or multiple days and I see no reason why resolvers do not
apply minimal and/or max caching rules that are reasonable.

Olafur

On Fri, Dec 1, 2017 at 3:48 PM, Giovane C. M. Moura <giovane.moura@sidn.nl>
wrote:

> Hi,
>
> In the light of the recent discussions on TTL violations and server
> stale here on the list, I decided to take a look on how often resolvers
> perform TTL violations in the wild.
>
> To do that, I used almost 10K Ripe Atlas probes. You can find a report
> and datasets at:
>
> https://labs.ripe.net/Members/giovane_moura/dns-ttl-
> violations-in-the-wild-with-ripe-atlas-2
>
> Now, what was more scary were the violations that *increased* the TTL of
>  of RR some more than 10x. That may put users at risk of service domains
> that may have been already taken down.
>
> /giovane
>
> ps: related thread on oarc list at :
> https://lists.dns-oarc.net/pipermail/dns-operations/2017-
> November/017039.html
>
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