CentOS 8.x Control Web panel Dovecot IMAP Connection Limit Configuration

Dovecot IMAP Connection Limit Configuration

Objective: Increase the maximum number of concurrent IMAP connections allowed per user per IP address in Dovecot.

Step 1: Update IMAP Configuration File

Open the Dovecot IMAP configuration file:

vim /etc/dovecot/conf.d/20-imap.conf

Locate the following line:

mail_max_userip_connections = 10

Change the value from 10 to 30:

mail_max_userip_connections = 30

Save the file and exit the editor.

Step 2: Restart Dovecot Service

Restart the Dovecot service to apply the changes:

systemctl restart dovecot

Step 3: Verify the Configuration

Verify that the updated value is applied:

dovecot -a | grep mail_max

Expected Output:

mail_max_userip_connections = 30

Alternative Method (If the Change Is Not Applied)

If the above steps do not override the default value, follow the steps below.

Open the main Dovecot configuration file and add the configuration at the bottom:

vim /etc/dovecot/dovecot.conf

Add the following line:

mail_max_userip_connections = 30

Save the file and restart the Dovecot service:

systemctl restart dovecot

Verify the changes again:

dovecot -a | grep mail_max

Expected Output:

mail_max_userip_connections = 30

Notes:

Increasing this value helps prevent IMAP login issues when multiple connections are initiated from the same IP.
Ensure this change aligns with server capacity and usage patterns.