[Pdns-users] cache expiry problem with pdns-recursor 3.1.4

Juergen Georgi georgi at belwue.de
Thu May 10 07:05:38 UTC 2007

Good morning,

On May 10,  8:13, bert hubert wrote:
> Subject: Re: [Pdns-users] cache expiry problem with pdns-recursor 3.1.4
> On Fri, May 04, 2007 at 03:44:27PM +0200, Juergen Georgi wrote:
> > four valid NS records expire after 12 hours. The fifth
> > (delphi.bsz-bw.de) expires after one day. This is bad,
> > because the recursor uses incomplete delegation data half
> > of the time. Then you see only one NS RR:
> This is not supposed to happen with recent versions of the PowerDNS
> recursor. Can you double check you are in fact running 3.1.4?

Version is reported as

"PowerDNS Recursor 3.1.4 $Id: pdns_recursor.cc 917 2006-11-07 12:23:51Z ahu $"

In the meantime our customer has fixed the NS rrsets of
zone bsz-bw.de, so the problem can no longer be reproduced.
The different default TTLs of the two masters have not
been corrected. Peeking at the cache dump, I now see

bsz-bw.de. 5414 IN NS dns1.belwue.de.
bsz-bw.de. 206 IN NS dns1.belwue.de.
bsz-bw.de. 5414 IN NS dns3.belwue.de.
bsz-bw.de. 206 IN NS dns3.belwue.de.
bsz-bw.de. 5414 IN NS uranos.rz.uni-konstanz.de.
bsz-bw.de. 206 IN NS uranos.rz.uni-konstanz.de.

Basically, the screwed setup was:

Master A announces:

$TTL 86400
example.com   NS B
example.com   NS X
example.com   NS Y

Master B announces:

$TTL 43200
example.com   NS A
example.com   NS X
example.com   NS Y

Slave X uses Master A
Slave Y uses Master B



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