[Pdns-users] powerdns internals

Martin domains at crystalline.nl
Fri Oct 30 15:07:13 UTC 2015


Hi,

I have a question about how Powerdns works internally after having read 
the documentation at 
https://doc.powerdns.com/md/authoritative/internals/

 From the documentation:

"When a query for a qname/qtype tuple comes in, PowerDNS queries 
backends to find the closest matching SOA, thus figuring out what 
backend owns this zone. When the right backend has been found, PowerDNS 
issues a qname/ANY query to the backend. If the response is empty, 
NXDOMAIN is concluded. If the response is not empty, any contents 
matching the original qtype are added to the list of records to return, 
and NOERROR is set."

What happens when the response of the ANY query is not empty but is not 
of the original qtype? Like in the problem I posted about yesterday: 
when a client is asking for the MX record of abc.example.com the ANY 
query that Powerdns executes will return one MySQL row with an A record 
for abc.example.com. Since that A record is not the original qtype MX 
shouldn't Powerdns also conclude NXDOMAIN then? Somehow it seems to me 
this is not what is happening right now.

Martin





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