IMAP4

This service allows users to access their account using any standard IMAP4 mail client (such as Outlook). IMAP4 offers a more advanced mail client experience with features such as multiple folders, mail uploading, flag control, and most importantly its ability to synchronize correctly between multiple mail clients. Using the available options in this service, the administrator can control the listening port, manage security and set up SSL.

IMAP4

  • Enable Service - This controls whether the service is enabled.
  • Ports - This controls which ports the service will listen on. It is recommended that you keep the default value of 143 as this is the standard IMAP4 port. To set multiple ports, simply separate each port with a semi-colon (';').
  • Max Connections - This controls the maximum number of simultaneous connections the service will allow. It is recommended that this value be no higher than 200.
  • Idle Time-out - If a connection remains idle, this value will control the period of time before the connection is forcefully shutdown.
  • Use Server Default - If selected, this will bind the ports to the IPs specified by the General settings.
  • Bind to All Available IPs - If selected, this will bind the ports to all available IPs.
  • Listen Only on IP(s) - If selected, this will bind the port to the IPs listed here. To set multiple IPs, simply separate each IP with a semi-colon (';'). Also, it is acceptable to specify a domain name instead of an IP.
  • Use Explicit SSL - This allows incoming connections to use the STARTTLS command to initiate a secure TLS connection.
  • Use Implicit SSL - This allows a secondary dedicated port for secure SSL connections to be opened. The implicit SSL port will also be affected by all the normal port bindings and limits.
  • SSL Ports - This controls which ports the SSL part of the service will listen on. It is recommended that you keep the default value of 993 as this is the standard IMAP4 SSL port. To set multiple ports, simply separate each port with a semi-colon (';').
  • Certificate - This option controls which SSL certificate will be used for SSL sessions. For more information on how to edit the SSL certificates, please view the SSL Certificates page.
  • SSL Mode - This controls which SSL / TLS mode will be used for SSL sessions.
  • Enable Anti-Hammering - Enabling this option will protect the service against brute force password guessing attacks. If an IP performs too many login failures, that IP will be prevented from logging in again for a set period of time. For more information, please view the General page.

IP Restrictions

  • Enable Blocked IPs - If enabled, the IPs and IP ranges in the list box will be blocked from accessing the service.
  • Enable Safe IPs - If enabled, the IPs and IP ranges in the list box will always be allowed access to the service. This protection overrules blocked IPs but does not overrule Anti-Hammering.

Miscellaneous

  • Subscribe New Mailboxes Automatically - If enabled, the subscribed folder list of the account will be automatically updated by any IMAP4 folder actions which create, rename or delete folders. This is useful when using a mail client which does not correctly manage the subscribed folder list.
  • Automatically EXPUNGE Deleted Mail - If enabled, any mail that gets flagged as deleted will cause an automatic EXPUNGE of the selected account directory, therefore causing such mails and any others marked for deletion to be actually deleted straight away. This avoids having to manually trigger an EXPUNGE / purge that most clients require.