Configuring Server-Wide Mail Settings

By default, Plesk works in cooperation with mail server software, which
provides email services for mailboxes and mailing lists. After
installation, the mail server is configured automatically and is ready
to serve. However, we recommend that you review the default settings to
make sure that they satisfy your needs.

To view or configure the mail service settings:

Go to Tools & Settings > Mail Server Settings (in the Mail
group).

General

1. Leave the Enable mail management functions in Plesk checkbox
   selected if you want to allow your users to create mail accounts
   through Customer Panel and use the mail services provided by the
   Plesk-managed mail server. If you are using an external mail server,
   clear this checkbox.

2. You can change the Installed mail server and Installed
   IMAP/POP3 server by using the corresponding links that lead to the
   Plesk Installer GUI page.

3. If you want to limit the size of an email message that can be sent
   through your server, type the required value in kilobytes into the
   Maximum message size box. Otherwise, leave this field blank.

4. In Plesk for Linux, you can change the default mail server limits on
   the number of concurrent connections that mail users can make to the
   server. This is useful, for example, for mail hosters who need to
   increase the number of concurrent connections to the mail server.

   Also, you can change the limit on the number of connections from the
   same IP address. A low limit impacts users who connects to the mail
   server from multiple computers from behind a firewall, as well as
   users who have more than one mail account.

   Note that to set up adequate numbers, you should estimate not only
   the possible total number of connections, but also the memory and CPU
   resources of the server.

   The total number of connections is counted as a sum of all
   connections made via the same protocol(IMAP, POP3, IMAP over SSL/TLS,
   or POP3 over SSL/TLS), so a single limit works for any of the
   protocols.

   If you use Courier IMAP, you can specify the following limits:

   • Maximum number of connections (IMAP, POP3, IMAP over SSL/TLS,
     or POP3 over SSL/TLS). This represents the maximum number of…