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

[Michael]

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
=====================================================================================