[Pdns-users] max-negative-ttl does not work

[Nico CARTRON]

On 09-Jan-2019 10:46 CET, <s.priebe at profihost.ag> wrote:

> Hi,
> 
> Am 09.01.19 um 09:53 schrieb Nico CARTRON:
> > On 09-Jan-2019 09:39 CET, <s.priebe at profihost.ag> wrote:
> > 
> >> Hi Nico,
> >>
> >> Am 09.01.19 um 09:33 schrieb Nico CARTRON:
> >>> Hi Stefan,
> >>>
> >>> On 09-Jan-2019 09:19 CET, <s.priebe at profihost.ag> wrote:
> >>>
> >>>> Dear List,
> >>>>
> >>>> i'm trying to get max-negative-ttl to work but i can't.
> >>>>
> >>>> # dpkg -s pdns-recursor  | grep Version
> >>>> Version: 4.1.8-1pdns.stretch
> >>>>
> >>>> # grep max-negative-ttl /etc/powerdns/recursor.conf
> >>>> max-negative-ttl=30
> >>>>
> >>>> # dig -t A unknowndomainxyz.multi.hiddendomain.de
> >>>> ...
> >>>> ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 26437
> >>>> ...
> >>>>
> >>>> dumped cache:
> >>>>
> >>>> # grep "unknowndomainxyz.multi.hiddendomain.de" /cachefile
> >>>> unknowndomainxyz.multi.hiddendomain.de. 3588 A  ; tag 0
> >>>>
> >>>> Why is the TTL 3588 when max-negative-ttl is set to 30?
> >>>
> >>> Just did a quick check on one of my Recursor, version 4.1.8 running on
> >>> FreeBSD, and max-negative-ttl works as expected (i.e. if I set it to 30
> >>> seconds, I correctly get this back, should it be with a dig or when
> >>> dumping the cache).
> >>>
> >>> Did you forget to restart the recursor after having changed the value in
> >>> the recursor.conf? Cause the 3600 value is the default one.
> >>
> >> No it was def. restarted after changing the config.
> >>
> >> See below:
> >> # rec_control get-parameter max-negative-ttl
> >> max-negative-ttl="30"
> >>
> >> Greets,
> >> Stefan
> >>
> > 
> > So I did the test on a Debian Stretch, with the same version as you:
> > 
> > root at vm-pdns1-lab:/etc/powerdns# dpkg -s pdns-recursor |grep Version
> > Version: 4.1.8-1pdns.stretch
> > 
> > and I also got it working.
> > 
> > Do you mind sharing your entire recursor.conf configuration file?
> 
> Do i can provide it - just an idea. I'm talking about a Subdomain wich
> is missing / NXDOAIN - the domain itself exists with a TTL of 3600.

Please share it :)
Also, please share the domain name you are testing with, not
"hiddendomain.de" - see
https://blog.powerdns.com/2016/01/18/open-source-support-out-in-the-open/

> Did you test a subdomain, where the real domain exists?

Yes, the domain I tested with exists indeed.


-- 
Nico