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

[Jan Huijsmans]

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 0.0.0.0/0,::/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