[Dnsmasq-discuss] min-cache-ttl overriding neg-ttl

[Glenn Fowler]

Hi,

I am caching positive responses for 40 minutes (min-cache-ttl), but want
negative responses cached for only 1 minute. If the forward zone server is
down momentarily, all of the queries during that time could result in an
erroneous negative response that gets cached for 40 minutes and unreachable
during that time instead of the desired 1 minute.

With neg-ttl working as expected, a retry after the 1 minute mark would
result in a positive response.

In general, negative responses shouldn't have a high TTL.

On Tue, Sep 20, 2022 at 4:59 PM Geert Stappers via Dnsmasq-discuss <
dnsmasq-discuss at lists.thekelleys.org.uk> wrote:

> On Tue, Sep 20, 2022 at 10:41:29AM -0400, Glenn Fowler wrote:
> > Hello,
> >
> > I have observed that if min-cache-ttl time is greater than neg-ttl time,
> > then the neg-ttl time is ignored and negative responses are cached at the
> > min-cache-ttl time.
> >
> > The expected behavior should be that neg-ttl is independent of
> > min-cache-ttl.
>
> What are the negative effects of it?   (a.k.a. With which priority needs
> it further attention?)
>
>
> > In searching I did find that unbound had the exact same issue:
> > https://github.com/NLnetLabs/unbound/issues/533
> >
> > I am on v2.86 on OpenWrt
> >
> > Thank you
>
> Thanks for what?
>
>
> Groeten
> Geert Stappers
> --
> Silence is hard to parse
>
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