Since Parallels Plesk Panel 8.4 version it is possible to limit maximum number of recipients for an e-mail message.
To prevent your users from sending mass e-mail:
maxrcptin the directory
$QMAIL_ROOT_Dis the location defined in the
Note: The number defined in the
maxrcpt file also affects sending messages to mailing list or mail group subscribers. That is, if you set the value to 100, then only 100 subscribers will receive the message sent to a mailing list or a mail group.
When you no longer need to restrict the number of recipients, delete the