To prevent your users from sending mass e-mail, do the following:
where $QMAIL_ROOT_D is the location defined in the file /etc/psa/psa.conf file.
Note that this number also affect sending of 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 the mailing list or mail group.
When you no longer need to restrict the number of recipients, delete the maxrcpt
file.