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.
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:
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.
Other ways to set up the external SMTP server settings:
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.
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:
If you do not set the external SMTP server, no outgoing mail services will be available.
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:
Note thatall the files and folders containing mail data of your subscribers remain on Plesk server.
Important: 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.