Using the mail server in Plesk is optional. Plesk for Linux allows you to switch off (uninstall) the mail service for all domains hosted on your server. On the Windows hosting, you cannot switch off the default mail server, but you can change its configuration to prohibit outgoing mail. Also, you can exclude the mail server from the installed components during Plesk installation.

However, when the mail server is not installed or prohibited from sending outgoing mail, you face the problem: Plesk still needs to send notifications, and customers’ scripts may need to send emails. To solve this problem, Plesk can send outgoing mail through an arbitrary external SMTP server.

Using an External SMTP Server for Outgoing Mail (Linux)

When the Plesk-managed mail server is not installed, Plesk uses the built-in SMTP client to send mail through the specified external SMTP server. By default, the client is not installed, and the link External SMTP Server is not available in Tools & Settings > the Mail group. Plesk allows you to install the client only instead of the Plesk-managed mail server.

To use the external SMTP server:

  1. Uninstall the Plesk mail server and install the SMTP client: In Tools & Settings > Updates > Add/Remove Components > Mail hosting features select MSMTP (relay only) instead of the selected mail server.

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    After you have uninstalled the Plesk mail server, customers cannot use mail services. For details, see Customer Panel Functionality Without the Mail Server below on this page.

  2. Set the SMTP server in Tools & Settings > External SMTP Server (in the Mail group) and select at least one of the options:

    • Allow Plesk to send email notifications through this SMTP server
    • Allow users’ scripts to send mail through this SMTP server

    Other ways to set up the external SMTP server settings:

    • By the command line utility mailserver (the --update-smtp-settings command)
    • By XML API requests with the server operator (set.prefs operation)

  3. If the SMTP server requires authentication, you need to notify site owners about the credentials (Username and Password) that they should use in their scripts to enable the scripts to send mail.

Plesk will send notifications and mail generated by scripts through the specified external SMTP server. Note that if you do not specify the external SMTP server settings, no mail services will be available.

After you install the client, only one link - External SMTP Server - will be found in Tools & Settings > the Mail group.

Note: If you exclude the mail server from the list of components during Plesk installation, the SMTP client is automatically installed instead of mail server software. In this case, you will be prompted to provide the SMTP client settings during Plesk installation.

Using an External SMTP Server for Outgoing Mail (Windows)

Plesk for Windows has a built-in SMTP client that sends outgoing mail to the SMTP server specified in Tools & Settings > External SMTP Server (in the Mail group).

By default, the option Use the mail server installed with Plesk and the default mail account created by Plesk is switched on. This means that the mail server installed with Plesk is used as an external SMTP server, so that Plesk sends all outgoing mail through the Plesk’s mail server. Plesk automatically creates a mail account with administrator’s rights to access the locally installed mail server. The password of this account is not displayed on this page.

When you prohibit outgoing mail from the Plesk’s mail server, you can set up another SMTP server in order to enable Plesk to send notifications and email messages generated by hosted scripts:

  1. Specify another SMTP server and user account in Tools & Settings > External SMTP Server (in the Mail group). To display the SMTP server settings, clear the option Use the mail server installed with Plesk and the default mail account created by Plesk.
  2. Select the option Allow Plesk to send email notifications through this SMTP server. Plesk will send notifications through the specified external SMTP server.
  3. To enable hosted scripts to send mail, notify site owners that their scripts should use the updated SMTP server settings.

If you do not set the external SMTP server, no outgoing mail services will be available.

Customer Panel Functionality Without the Mail Server

With the mail server uninstalled, Plesk does not provide mail-related functionality for your subscribers. The Mail section and UI elements related to mailboxes are not available. In addition, other changes take place when no mail server is installed:

  • Webmail is not available.
  • Users cannot install APS applications that require mail service.

Note thatall the files and folders containing mail data of your subscribers remain on Plesk server.

Note: When you perform transfer of domains from Plesk with a mail service to Plesk without the mail service, all the data that concerns domains’ mailboxes is not transferred.