[dnsdist] how to increase connection qlen on DoH listener?

[Otto Moerbeek]

On Sun, Mar 29, 2020 at 06:20:00PM +0000, Christoph via dnsdist wrote:

> Hi,
> 
> due to log entries saying:
> "Listen queue overflow: 193 already in queue awaiting acceptance"
> we increased
> kern.ipc.somaxconn to 2048
> 
> 
> after restarting dnsdist we noticed that while nginx takes
> the new setting into account dnsdist remains at 128:
> 
> netstat -Lan
> Current listen queue sizes (qlen/incqlen/maxqlen)
> Proto Listen
> tcp4  0/0/128      <<< dnsdist
> tcp4  5/0/2048     <<< nginx
> 
> 
> Is there a way to tell dnsdist to increase the connection queue on the
> DoH listener?
> 
> I didn't not see something like that in the documentation:
> https://dnsdist.org/reference/config.html?highlight=adddohlocal#addDOHLocal
> 
> 
> This is on FreeBSD 12.1 with dnsdist v1.4.0
> 
> thanks,
> Christoph
> 
> 
> refs:
> 
> kern.ipc.somaxconn: Maximum listen socket pending connection accept
> queue size
> 
> from FreeBSD netstat(1) manual page:
> -L      Show the size of the various listen queues.  The first
>         count shows the number of unaccepted connections, the
>         second count shows the amount of unaccepted incomplete
>         connections, and the third count is the maximum number of
>         queued connections.
> 

Reading https://www.freebsd.org/doc/en/books/handbook/configtuning-kernel-limits.html
I would expect that you want to increase kern.ipc.soacceptqueue

	-Otto