(Plesk for Linux) Using Other Mail Server Software

Plesk is shipped with the Postfix and Qmail mail servers. For IMAP and POP3 delivery, you can use the Dovecot or Courier IMAP mail servers. We recommend that you use Dovecot, which is the default IMAP server in Plesk. Compared to Courier IMAP, Dovecot is faster, more secure, consumes fewer server resources, and provides support for server-side mail filtering rules.

You can switch between the mail servers in Tools & Settings > Updates > Add/Remove Components > Mail hosting features or in Tools & Settings > Mail Server Settings.

Plesk will start using the new mail server without any need for server restart. You can select another mail server at any time later.

Notes on switching to Dovecot:

  • Dovecot comes with Piegeonhole – server-side filtering engine, which can be configured from webmail interface and third-party extensions to mail user agents (MUAs) like Thunderbird.
  • Dovecot supports pushing email through “IMAP IDLE” and optional “IMAP NOTIFY” protocol extensions.
  • Dovecot uses Sieve language to define server-side filtering rules.
  • Due to high diversity of Dovecot versions in OS vendor repositories, we build our own packages. Many Dovecot features that do not make much sense in Plesk context are left out (the provided version is built without their support).
  • Dovecot does not support short mail account names with Qmail and POP3 authorization before SMTP.
  • Switching back to Courier IMAP from Dovecot is not recommended, especially if a large number of new email messages have been received: This will cause re-downloading of email messages by mail clients.
  • If you used SSL/TLS certificates with Courier IMAP, you can reuse them with Dovecot. To do this, take either /usr/share/pop3d.pem or /usr/share/imapd.pem file, and save it to /etc/dovecot/private/ under the name ssl-cert-and-key.pem. Make sure that the new file has the 0400 root:root permissions. After that restart the Dovecot service.

(Plesk for Windows) Using Other Mail Server Software

Apart from the default mail server (MailEnable), Plesk for Windows supports IceWarp (Merak) and SmarterMail, which are not shipped with Plesk and must be installed separately.

The procedure below describes how to set up a local mail server. You can also use a remote mail server (namely, SmarterMail) instead of the local one. Learn how to set up a remote SmarterMail server.

To set up IceWarp or SmarterMail in Plesk:

  1. To use SmarterMail Free, go to Tools & Settings > External SMTP Server (under “Mail”), clear the “Use the mail server installed with Plesk and the default mail account created by Plesk” checkbox, and then click OK.

    If you use IceWarp or paid SmarterMail editions, you can skip the current step and go to the next one.

    Note: SmarterMail Free supports one domain with up to 10 mailboxes. If the checkbox described above is selected, Plesk automatically creates the localhost domain for technical needs. This domain uses up the one-domain limit set by SmarterMail Free, and SmarterMail installation in Plesk fails.

  2. Download and install the mail server software according to the instructions provided by the mail server manufacturer.

  3. Log in to Plesk and go to Tools & Settings > Server Components > the Mail Server link.

    The mail server you have installed should now be displayed in the list of available mail servers.

    Note: When configuring the SmarterMail server, either specify as the hostname or keep the field empty.

  4. Select the mail server you need and click OK.

Plesk will start using the new mail server without any need for server restart. You can select another mail server at any time later.

Note: SmarterMail mail server allows you to turn on the Require SMTP Authentication option on the domain level. However, this option can be turned on only when open relay is selected on the server level in Plesk. With other relay modes, Plesk turns off this option. To turn on this option, allow open relay in Plesk as described in the Configuring Server-Wide Mail Settings section and go to SmarterMail > Settings > Defaults > Domain Defaults.