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For cPanel & WHM version 11.50

(Home >> Service Configuration >> Mailserver Configuration)

Overview

The following options appear when you access WHM's Mailserver Configuration interface while you run the Dovecot mail server. 

Note:

Select your mailserver in WHM's Mailserver Selection interface ( Home >> Service Configuration >> Mailserver Selection ).

Mailserver Configuration options

Choose the desired settings for each option in the table below, and then click Save.

  • To return to the default values for all configuration options, click Use Default Values.
  • To undo your changes, click Reset. 

Configuration optionDescription
Protocols Enabled

Select the checkboxes to enable the desired protocols.

Warning:

  • If you attempt to save the configuration without a protocol, WHM disables the Mailserver Configuration feature.
  • To reenable the Mailserver Configuration feature, select a mail server in WHM's Mailserver Selection interface (Home >> Service Configuration >> Mailserver Selection).

Note:

cPanel’s Webmail feature requires that you enable the IMAP protocol.

IPv6 Enabled

Select the checkboxes to enable IPv6 address connection requests on the desired protocols.

Important:

You must select the desired protocols' Protocols Enabled checkboxes before you select those protocols' IPv6 Enabled checkboxes.

Allow Plaintext Authentication (from remote clients)

This setting allows remote email clients to authenticate without encryption. Select the desired option from the menu:

  • yes — Dovecot allows remote connections to authenticate without encryption.
  • no — Dovecot only allows connections that originated on the local server to authenticate without encryption. 

Note:

We recommend that you set this option to no if you wish to require remote webmail logins to use encryption.

SSL Cipher List

The list of ciphers, in standard format, that the mail server can use to connect to your server with the POP3 protocol.For more information, read OpenSSL's ciphers documentation .

SSL ProtocolsThe list of SSL protocols that the mail server uses. Typically, you will only adjust this setting for PCI compliance.
Maximum Number of Mail ProcessesThe maximum number of mail processes that may run at one time.
Maximum Size of a Mail Process (MB)

The maximum amount of memory that the IMAP and POP3 processes may use, in Megabytes.

Because these processes mainly read memory-mapped files, a large maximum should not adversely affect your server's performance.

Maximum IMAP Connections Per IP Address

The maximum number of simultaneous IMAP connections that one IP address's mail server may make.

Note:

The system only applies this setting if you enabled an IMAP protocol. 

Interval between IMAP IDLE "OK Still here" messages

The number of minutes between IMAP IDLE "OK Still here" messages.

Note:

You may wish to increase this number in order to increase battery life for mobile clients.

Maximum POP3 Connections per IP Address

The maximum number of simultaneous POP3 connections that one IP address's mail server may make.

Note:

The system only applies this setting if you enabled a POP3 protocol. 

Number of Spare Authentication ProcessesThe number of spare authentication processes to run to listen for new connections.
Maximum Number of Authentication Processes

The maximum number of authentication daemons that can run simultaneously. Consider the needs of your mail server before you enter a value that is not the default value.

Notes:

  • A high number of authentication daemons can cause your server to run slowly. Authentication daemons can consume large amounts of system resources.
  • A low number of authentication daemons can cause your server to run slowly due to a lack of daemons to authenticate each session.

Maximum Size of a Authentication Process (MB)The maximum amount of memory that the IMAP and POP3 authentication processes may use, in Megabytes.
Size of Authentication Cache (KB)

The maximum amount of space on the hard drive that the cache file may use, in Kilobytes.

  • The cache file contains validated logins. 
  • This allows the mail server to retrieve mail multiple times before it must check login credentials again.
Time to Cache Successful Logins

The amount of time, in seconds, that the cache file stores a successful login attempt's record.

Note:

You may wish to lower this value to decrease the likelihood of problems when users update their passwords. 

Time to Cache Failed Logins

The amount of time, in seconds, that the cache file stores a failed login attempt's record.

Note:

You may wish to lower this value to decrease the likelihood of problems when users update their passwords. 

Use New Authentication Process for Each Connection

Whether the mail server uses a newly-created authentication process each time that a connection attempt occurs. Select yes to improve Dovecot security. 

Note:

Heavily-loaded servers may experience significant performance issues if you select yes.

Idle Check Interval

The amount of time, in seconds, between updates to idle IMAP connections.

Notes:

  • We recommend that you use the default setting (30 seconds).
  • You may lower this value to cause idle clients to see new messages faster. 
  • Lower values may increase your server load slightly.
Auto Expunge TrashSelect this checkbox to allow the system to delete messages in the Trash folder based on the number of days that you configure in the Trash Expire Time option. 

This option defaults to disabled.
Trash Expire Time

The number of days that the mailserver should keep messages in the Trash folder before the Auto Expunge Trash option deletes the messages. 

This option defaults to 30 days. 

Note:

This option is only active when you enable the Auto Expunge Trash option.

Add Dovecot options

You can also add options that do not exist in the Configure Dovecot interface to configure the Dovecot mail server. To do this, perform the following steps:

  1. Create and open the /var/cpanel/conf/dovecot/main file with a text editor.
  2. Edit the file to reflect your desired settings, for example:

    login_trusted_networks: 192.168.1.0/24

    Note:

    $body

  3. Save your changes to the file.
  4. Rebuild the Dovecot mailer server to apply the new configuration settings. To do this, run the following script:

    /usr/local/cpanel/scripts/builddovecotconf 
  5. Restart the Dovecot mail server. To do this, run the /scripts/restartsrv_dovecot command.