I haven't found a Virtualmin option to enforce submission and smtps check for outgoing mail from mailboxes
The problem is that a logged user can send emails from any address because postfix, by default, doesn't check that
the directives to enable are smtpd_sender_login_maps in main.cf reject_sender_login_mismatch in master.cf
also the smtpd_sender_login_maps needs a table in the "mails sasl_login" format so the /etc/postfix/virtual doesn't work
I've created a script that can do it automatically:
#!/bin/bash
if [ "$(id -u)" = "0" ]; then
echo -n "" > /etc/postfix/login_map
for usermail in $(virtualmin list-users --all-domains --email-only)
do
echo "$usermail" "$usermail" >> /etc/postfix/login_map
done
postmap /etc/postfix/login_map
fi
it is raw but works