[Pdns-users] pdns-recursur 4.4: host unknown after some time with no clear reason

Jan Huijsmans bofh at koffie.nu
Tue Jun 7 13:34:44 UTC 2022

Hi Frank,

On Wed, 1 Jun 2022 12:48:01 +0200
"frank+pdns at tembo.be" <frank+pdns at tembo.be> wrote:

> Hi Jan,
> I completely understand NDAs and myself (and numerous other PowerDNS
> Certified Consultants on this list) are happy to sign them, as part
> of a professional engagement. Please reach out to me off-list to
> discuss your options.
> However, this also means that on this list, we can't help you much...
> As per your questions: first we need to know what happens. The trace
> should tell us. Options to look at: (yes this list is long and some
> won't apply, but please reread the first sentence of this mail)
> * https://doc.powerdns.com/recursor/settings.html#network-timeout

I'm getting the feeling this is the culprit. We looked at the nsspeeds
the recursor reported and saw times between 0.6 and 1.2s for the
root servers just after a restart of de recursor.

I now get reports that the admins see 2s responce times in their
environment, making the default of 1.5s timeout a tad close to the
times observed in a clean environment and to low for reported times.
We instructed to set the network-timeout to 3000 or even 5000.

> *
> https://doc.powerdns.com/recursor/settings.html#dont-throttle-netmasks

We already set this to,::/0 and kept seeing the issues.

The local admins are keeping an eye on the environment with the new
settings and will report back.


Jan Huijsmans              bofh at koffie.nu

... cannot activate /dev/brain, no response from main coffee server

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