[dnsdist] dnsdist 1.4 and Debian Buster

abang at t-ipnet.net abang at t-ipnet.net
Fri Aug 9 07:50:41 UTC 2019

Hi Chris,

Maybe I missed that in this thread, but did you try with turning off connection tracking or rising conntrack kernel table size? dmesg might you show wether connection tracking limit was exceeded.


Am 9. August 2019 05:46:54 MESZ schrieb Chris <lists+pdns at gbe0.com>:
>Hi Remi,
>I deployed a new copy of a PowerDNS authoritative server on Debian 
>Buster and ran into a similar problem but with a slight twist. As with 
>dnsdist I use multiple instances of PowerDNS which use different SQL
>As with dnsdist, after a period of time I stopped being able to make
>queries but TCP queries worked fine. The built in web server also works
>(I guess because its TCP). This happened to all instances on the server
>at the same time (even an instance which only gets health check queries
>from a few dnsdist servers).
>I wanted to see if I could see anything different comparing a working 
>instance with a not working instance on the same server so I restarted 
>one of the instances. When I restart that one instance all started 
>working again as expected. With that in mind it sounds like some sort
>limit gets hit. I do raise 'LimitNOFILE' and 'TasksMax' settings in a 
>systemd service.d file for each instance already.
>As with dnsdist I couldn't find anything in the system logs indicating 
>why. The auth servers have the same configuration and server setup as I
>was running on Debian Stretch - I deploy a minimal install with puppet 
>installed and it will deploy the rest.
>On 8/08/2019 9:15 pm, Remi Gacogne wrote:
>> Be careful that dig (the 9.14.4 I have here at least) uses TCP by
>> default for ANY queries so you might need a +notcp to actually test
>Thanks, I double checked and it is using UDP for those queries.
>I'll have to keep digging to see if I can find out why, as of now I 
>don't understand why its happening like this.
>dnsdist mailing list
>dnsdist at mailman.powerdns.com
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