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

[Leen Besselink]

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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