[Pdns-users] pdns stops responding to requests

Brandon Checketts brandonc at webpipe.net
Tue Dec 19 02:01:35 UTC 2006


Thank you for your response.  I'm running version 2.9.20 that was installed from
the pdns-static-2.9.20-1 RPM.  UDP is definitely failing, not sure about TCP as
we get very few TCP Requests.

I've just installed strace, and can run it.  Each pdns_server-instance processes
display different things, but I'm not a programmer, so I don't understand much
of the output.   I can pick out the three processes that are doing the MySQL
queries, and the one that looks like its receiving/sending the actual DNS
traffic, so I will do an strace on it the next time that it fails to see if it
identifies anything.  I will also try the pdns "dump" and see if that reveals

I looked at a tcpdump that I had running at the time of a failure and didn't see
anything unusual, just DNS requests, MySQL lookups/replys and DNS answers.
Then, when it fails, only incoming DNS requests with no other traffic until it
is restarted.

Brandon Checketts
Webpipe.net System Administrator

Augie Schwer wrote:
> On 12/17/06, Brandon Checketts <brandonc at webpipe.net> wrote:
>> I've just replaced two BIND servers with PowerDNS Servers.   They are
>> configured
>> to use the gmysql backend, and MySQL is performing the replication
>> between them.
>>   Everything seems to be working fine, but on the "slave" server, pdns
>> seems to
>> just quit responding to DNS requests sometimes.   The web server
>> portion of it
>> continues to respond, but DNS queries just don't get answered.   Also,
>> when it
>> locks up, a netstat -l -n shows this (notice the Recv-Q for udp on
>> port 53):
> What version are you running? If there is nothing in the logs, then
> you can try straceing one of the threads to see if that reveals any
> more info. Is it both UDP and TCP that stop responding? Did you try
> tcpdumping on the interface to make sure you are receiving the
> requests. You can also look at the stats:
> /etc/init.d/pdns dump
> The latency and q-size stats may be revealing.

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