Dovecot "service(stats): client_limit (1000) reached" message

Symptoms

In some instances the following messages may occur in Dovecot:

dovecot: master: Warning: service(stats): client_limit (1000) reached, client connections are being dropped

Warning: service auth { client_limit=1000 } is lower than required under max. load (1124)

Both messages suggest that Dovecot's default_client_limit value need to be increased.

Description 

The above examples suggest that the Dovecot default_client_limit is not high enough and would need to be increased. However, the Dovecot configuration file builds from a template. As this is the case, the template needs to be adjusted with the new value.

Workaround

To work around your issue, a "local" template for Dovecot needs to be copied:

cp /var/cpanel/templates/dovecot2.3/main.default /var/cpanel/templates/dovecot2.3/main.local

Once this is created, add your new default_client_limit to the file:

echo "default_client_limit = 1200" >> /var/cpanel/templates/dovecot2.3/main.local

You can adjust this limit to your needs, though the value of 1200 is used as an example.

Lastly, rebuild Dovecot's configuration file, and then restart the service:

/scripts/builddovecotconf

/scripts/restartsrv_dovecot

To verify your changes, use the following command:

doveconf -a | grep default_client_limit