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This document is for a previous release of cPanel & WHM. To view our latest documentation, visit our Home page.

For cPanel & WHM 11.44

(Home >> Service Configuration >> Mailserver Configuration)

Overview

The following set of options will appear when you access WHM's Mailserver Configuration interface while you run the Courier mail server. 

Note:

You can choose a mailserver in the Mailserver Selection interface.

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

You can choose from the following protocols:

  •  IMAPD
  • IMAPDSSL
  • POP3D
  • POP3DSSL

Note:

cPanel’s Webmail feature requires that you enable standard IMAP.

Warning:

  • If you attempt to save the configuration without a protocol, WHM will disable the Mailserver Configuration feature.
  • To re-enable the Mailserver Configuration feature, select a mail server in the Mailserver Selection interface (Home >> Service Configuration >> Mailserver Selection).
Maximum IMAP Connections (Total)Defines the maximum total number of IMAP connections that are possible at any given time.
Maximum IMAP Connections per IP

Defines the maximum number of IMAP connections that are available to the mail server for one IP address.

This setting only applies when you enable IMAPS.

Maximum TLS/SSL IMAP Connections per IP

Defines the maximum number of secure IMAP over SSL (IMAPS) connections that are available to the mail server for one IP address.

This setting only applies when you enable IMAPS.

IMAP TLS/SSL ProtocolDefines which TLS or SSL protocols the server can use for a secure IMAPS connection. For more information about TLS/SSL, read the TLS/SSL section below. 
IMAP TLS/SSL Cipher ListThe list of ciphers, in standard format, that Courier can use to connect to your server with the IMAP protocol. For more information on ciphers, read OpenSSL's documentation.
IMAP Empty TrashSpecifies the number of days that a message remains in a trash folder before it is deleted.
Maximum POP3 Connections (Total)Defines the maximum number of simultaneous POP3 connections. This setting only applies if you enable POP3.
Maximum POP3 Connections Per IPDefines the maximum number of simultaneous POP3 connections that are available to the mail server for one IP address. This setting only applies if you enable POP3.
Maximum TLS/SSL POP3 Connections Per IPDefines the maximum number of simultaneous POP3 over SSL (POP3S) connections that are available to the mail server for one IP address. This setting only applies if you enable POP3.
POP3 TLS/SSL ProtocolDefines the TLS or SSL protocols that Courier can use for a secure POP3S connection.
POP3 TLS/SSL Cipher ListThe list of ciphers, in standard format, that Courier can use to connect to your server with the POP3 protocol. For more information on ciphers, read OpenSSL's documentation.
Number of Authentication Daemons

Defines the maximum number of authentication daemons that can run simultaneously. Consider the needs of your mail server before you enter a value other than the default value. 

Notes:

  • A high number of authentication daemons can cause your server to run slowly. This is because 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.

TLS/SSL

Transport Layer Security (TLS) and Secure Sockets Layer (SSL) are two cryptographic protocols that computers use for secure communication over the Internet. Email and web browsing often use these protocols. Essentially, they perform the same tasks.

Both of these protocols initiate a “handshake,” during which your server and the user’s computer will agree upon specific conditions. These conditions include, most importantly, a set of public and private keys that the two computers will use to encrypt and decrypt messages that they send during the secure session.

As a web server, your server will identify itself when it receives a request from a user. SSL will allow you to generate and sign your own certificates, which allow you to authenticate servers. However, we do not recommend self-generated, self-signed certificates, because they are generally not secure. Because self-generated, self-signed certificates do not use a third-party verification system, any server could claim to be your server. To remedy this, register with a certificate authority (CA). The CA independently verifies that visitors interact directly with the correct server.