[Pdns-users] powerdns internals

[Martin]

I'm still struggling to solve this problem.
When I compare both backends (one a custom queries and one a regular) 
and the queries they send to MySQL for a nonexistent subdomain MX 
record, it appears they basically both send the same type of queries and 
get the same kind of results/rows back. The only difference is that the 
custom queries backend fires two more queries *after* the 'SOA-EDIT' 
query (see below, which is the final query the regular backend sends): 
it queries again for SOA records for abc.example.com and then 
example.com .
Is there any reason why a DNS client or Powerdns would fire these SOA 
queries again? It already got the SOA record from the first two queries 
(see below). Thanks again for any pointers.

Martin


On 01-11-2015 16:10, Martin wrote:
> Hi,
> 
> It is somewhat helpful but doesn't solve my issues. I understand that
> to return NXDOMAIN my queries should not return data, but how can I do
> that when Powerdns uses ANY queries to fetch the data all the time?
> The only query types that I see in the MySQL logs are SOA, NS and ANY.
> If there are no MX records for abc.example.com but there is an A
> record for abc.example.com, my ANY query is never able to return 0
> rows. As I said, in that case I would expect Powerdns to filter out
> nonrelevant records.
> 
> FWIW, here's the order of queries in the MySQL logs when, for example,
> I query a nonexistent TXT record for abc.example.com . I have only
> listed queries relevant for the backend the domain example.com is in,
> since the other backend successfully returns no data at all for that
> domain.
> 
> type='SOA' AND domain='abc.example.com' => returns nothing
> type='SOA' AND domain='example.com' => returns 1 SOA record
> type='NS' => returns nothing (I'm not sure where this query is coming
> from because it resembles one of my custom queries but it is
> definitely not one of them?)
> ANY-ID query for abc.example.com => returns 1 row that contains an A 
> record
> PRESIGNED metadata query => returns nothing
> NSEC3PARAM metadata query => returns nothing
> type='SOA' AND domain='example.com' => returns 1 SOA record
> ANY-ID query for example.com => returns TXT record, 2 NS records, SOA
> record and an A record
> SOA-EDIT metadata query => returns nothing
> 
> Martin
> 
> 
> On 30-10-2015 17:29, bert hubert wrote:
>> On Fri, Oct 30, 2015 at 04:07:13PM +0100, Martin wrote:
>>> Hi,
>>> 
>>> I have a question about how Powerdns works internally after having
>>> read the documentation at
>>> https://doc.powerdns.com/md/authoritative/internals/
>> 
>> Martin,
>> 
>> Can you read
>> http://blog.powerdns.com/2015/06/23/what-is-a-powerdns-backend-and-how-do-i-make-it-send-an-nxdomain/
>> to see if it helps?
>> 
>> 	Bert
> 
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