ResolutionSince Parallels Plesk Panel version 8.4, it is possible to limit the maximum number of recipients for an email message. To prevent your users from sending mass emails, do the following:
1. Create a file named maxrcpt in the directory $QMAIL_ROOT_D/control/ where $QMAIL_ROOT_D is the location defined in the /etc/psa/psa.conf file.
2. Enter the number of allowed recipients in this file and save it.
Note that this number also affects the sending of messages to mailing lists or mail group subscribers. That is, if you set the value to 100, then only 100 subscribers will receive messages sent to mailing lists or mail groups.
When you no longer need to restrict the number of recipients, delete the maxrcpt file.