Increasing The Maximum Connections In Kerio Connect

Kerio has a few maximums set by default. There are also a few items that are not in the Kerio Connection Administration page. When using IMAP (and some other services), you can increase the maximum number of allowed connections to allow users to be able to connect to your servers using the variety of devices they likely now have. We’ll look at doing this with IMAP (given that each account accessed by each user is likely using at minimum 2 connections) but you can do this with many other services as well.

To increase the total number of available IMAP connections:

  • Open the Kerio Connect Administration page.
  • Click on the Configuration disclosure box to see Services.
  • Click on Services.
  • From the Services page, double-click on IMAP.
  • At the IMAP box, click on the Access tab.
  • Increase the field for Maximum number of concurrent connections.
  • Click OK.
  • Click Restart to restart the IMAP service.
Screen Shot 2013-04-03 at 8.44.28 AM Now, let’s say that all of the IMAP connections are coming from what the server sees as the same IP (somewhat common with certain types of routers). Well, there’s also a setting not exposed in the web configuration tool that limits the total number of connections available for a given IP address, so let’s go ahead and increase that as well. To do so, open the mailserver.cfg file located in /usr/local/kerio/mailserver. Here, look in the service-imap table and find the MaxConnectionsIP variable. Change that to, let’s say 300 and then save the changes and restart the IMAP service again. Now you’re done. Good luck!