[Resolved] Maximum number of concurrent DNS queries reached

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I have been working to find solutions based on the above concern; most posts on the forum explain in some regards how to troubleshoot to attempt to overcome this concern, and rarely have a guide or how-to, to resolve the concern in detail.

Below list the following detailed steps that were taking to attempt to resolve this concern:

  • Connect to pihole via SSH

  • Navigate to /etc/dnsmasq.d/

  • check to see if the following .conf exists on your Pihole instance
    02-custom-settings.conf

  • If this does not exist proceed with the following command
    sudo nano /etc/dnsmasq.d/02-custom-settings.conf

  • Add the following to the above .conf

#### EDIT SETTINGS
dns-forward-max=5096
min-cache-ttl=300
rebind-domain-ok=
#### END EDIT

  • Save and exit the config

  • Reboot your PiHole instance

From there you will want to monitor your instance of PiHole over the next few days to see if the following error reoccurs via PiHole GUI @

Tools > Pi-hole diagnosis

DNSMASQ_WARN Warning in `dnsmasq` core:
Maximum number of concurrent DNS queries reached (max: 150)"

To explain the above values:

dns-forward-max
this increases the max DNS forward limit, for busy internal network . Default limit is 150.... 1024+ is more realistic.

min-cache-ttl
This extends the minimum time-to-live settings for cached lookups and ensures all DNS lookups will be cached for at least 300 seconds. This is a very useful setting to take full advantage of caching nameserver capabilities.

rebind-domain-ok=
allows specific domains where DNS rebind support is needed.

At the preset time these changes above resolved the error on my current PiHole deployment. It has been a few days and the error has not reoccurred.

Hopefully this guided set of instructions assists others in the community, being that the community ranges from beginners to advanced users.
Please feel free to add any feedback to this information as I have been attempting to resolve this ongoing concern for some time.

Thanks to @will.foster for the assist

Thank you.

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