[Pdns-users] PowerDNS Recursor does not provide correct answer to Postfix

[Michael]

Hi,

thanks for the answer.

Since I can see the query from Postfix in the logs of PDNS_recursor, I  
assume Postfix is communicating with the recursor correctly.

Here is the content of /var/spool/postfix/etc/resolv.conf

root at mx0:~# cat /var/spool/postfix/etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1

Thanks,
Michael

Quoting Leen Besselink <leen at consolejunkie.net>:

> Hi,
>
> Sounds like a strange problem.
>
> Just to make sure it's set up correctly.
>
> Could you check that Postfix is talking to PowerDNS Recursor ?  
> Because Postifx has a seperate resolv.conf (which gets updated when  
> starting Postfix):
>
> /var/spool/postfix/etc/resolv.conf
>
> On Thu, Aug 18, 2016 at 02:20:25PM +0000, Michael wrote:
>> Hi all,
>>
>> I have been using pdns_recursor package on my Ubuntu 14.04 quite
>> some time to resolve host names locally. That worked fine for the
>> entire system.
>>
>> Last week I updated to Ubuntu 16.04. So I have a new Postfix version
>> (3.1.0) as well as a new pdns_recursor version (4.0.0-alpha2).
>>
>> Since this update Postfix does not receive correct answers for a
>> particular query anymore. Concretely, queries for A entries of
>> Office365 mail servers.
>>
>> For example if Postfix asks for the A entry of
>> nxp-com.mail.protection.outlook.com, pdns_recursor returns to
>> Postfix that there does not exists a A record.
>> However, if I manually do this query with dig, I do get an correct
>> answer. Please see the logs at the end of the mail.
>>
>> Besides the queries of Office365 mail servers, the rest is working
>> fine. I have no idea how to track down that issue? Is there any
>> setting in pdns_recursor I have to change?
>>
>> Thanks,
>> Michael
>>
>>
>> Postfix log
>> =====================================================================================
>> Aug 15 18:21:07 mx0 postfix/qmgr[2715]: 39EF2A40EA2:
>> from=<mine at michi.su>, size=865, nrcpt=1 (queue active)
>> Aug 15 18:21:08 mx0 postfix/smtp[2907]: warning: no MX host for
>> nxp.com has a valid address record
>> Aug 15 18:21:08 mx0 postfix/smtp[2907]: 39EF2A40EA2:
>> to=<test at nxp.com>, relay=none, delay=1492, delays=1492/0.12/0.81/0,
>> dsn=4.4.3, status=deferred (Host or domain name not found. Name
>> service error for name=nxp-com.mail.protection.outlook.com type=A:
>> Host not found, try again)
>> =====================================================================================
>>
>> pdns_recursor log after Postfix query
>> =====================================================================================
>> Aug 15 18:21:07 mx0 pdns_recursor[2512]: 1 [16/1] question for
>> 'nxp.com.|MX' from 127.0.0.1
>> Aug 15 18:21:08 mx0 pdns_recursor[2512]: 1 [16/2] answer to question
>> 'nxp.com.|MX': 1 answers, 0 additional, took 2 packets, 147.186 ms,
>> 0 throttled, 0 timeouts, 0 tcp connections, rcode=0
>> Aug 15 18:21:08 mx0 pdns_recursor[2512]: 2 [9/2] question for
>> 'nxp-com.mail.protection.outlook.com.|A' from 127.0.0.1
>> Aug 15 18:21:08 mx0 pdns_recursor[2512]: 2 [9/2] answer to question
>> 'nxp-com.mail.protection.outlook.com.|A': 0 answers, 1 additional,
>> took 9 packets, 595.218 ms, 3 throttled, 0 timeouts, 0 tcp
>> connections, rcode=2
>> =====================================================================================
>>
>> pdns_log after dig query
>> =====================================================================================
>> Aug 15 17:52:20 mx0 pdns_recursor[2520]: 2 [53/1] question for
>> 'nxp-com.mail.protection.outlook.com.|A' from 127.0.0.1
>> Aug 15 17:52:21 mx0 pdns_recursor[2520]: 2 [53/1] answer to question
>> 'nxp-com.mail.protection.outlook.com.|A': 2 answers, 1 additional,
>> took 2 packets, 111.056 ms, 0 throttled, 0 timeouts, 0 tcp
>> connections, rcode=0
>> =====================================================================================
>>
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