[Pdns-users] strange resolution problem

[bert hubert]

On Tue, Jun 22, 2010 at 02:31:44PM +0200, Mario Caruso wrote:
> Here is an except from the daemon log files, can someone  explain me what is happening ?

Hi Mario,

It is good to hear that you switched to PowerDNS. I hope it will work well
for you. Regarding the case below:

> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: Trying IP 213.92.11.34:53, asking 'www.cafsials.it.|A'
> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: Got 2 answers from ns2.register.it. (213.92.11.34), rcode=3, in 41ms
> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: accept answer 'www.cafsials.it.|CNAME|web.dataufficio.com.' from 'cafsials.it.' nameservers? YES!
> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: accept answer 'dataufficio.com.|SOA|ns1.register.it. hostmaster.register.it. 2004061701 10800 3600 604800 86400' from 'cafsials.it.' nameservers? NO!
> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: determining status after receiving this packet
> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: status=NXDOMAIN, we are done 

The problem here is that 'ns2.register.it' returns an authoritative NXDOMAIN
RCode. 

In this case, the NXDOMAIN is a lie, since you could actually decide to
'trust' that data.

However, it is generally not a good idea to make a nameserver program around
a bug of someone else.

In this case, it is nice that it works in BIND. If you measure, you find
that BIND and PowerDNS resolve about the same amount of domains correctly.
There will be some domains that work well in PowerDNS and not in BIND and
the other way around.

So please ask 'register.it' to solve their nameserver.

Kind regards,

Bert Hubert

PS: in powerdns recursor 3.3, this domain will start working anyhow after
the first query. So the practical problem is limited there.

> Jun 22 14:16:43 elan pdns_recursor[26638]: [2048] www.cafsials.it.: failed (res=3)
> Jun 22 14:16:43 elan pdns_recursor[26638]: 0 [2048] answer to question 'www.cafsials.it.|A': 1 answers, 0 additional, took 2
> packets, 0 throttled, 0 timeouts, 0 tcp connections, rcode=3



> _______________________________________________
> Pdns-users mailing list
> Pdns-users at mailman.powerdns.com
> http://mailman.powerdns.com/mailman/listinfo/pdns-users