Reject user mails to/from some domain.

Hello.
I have Ispconfig 2 Server.
I want to block some domains.
For example:
I want to block send and recive any mail from this domain: @example.com.
I have blocked recieving by adding smtpd_sender_restrictions = regexp:/etc/postfix/access line in /etc/postfix/main.cf file and "access" file, but cann't achieve block send.
How can i do it?
Rgds mixo.

 

I've solved this problem with this line in main.cf:
check_recipient_access regexp:/etc/postfix/access.
It blocks outgoing mail.
But still one problem.
It blocks when i send from Outlook, but from roundcube doesn't.
Any idea?

 

I've blocked sending mail from roundcube webmail to some domain by changing code in /home/admispconfig/ispconfig/web/roundcubemail/program/steps/mail/sendmail.inc:

PHP:

 if (strlen(strstr($mailto,'example.com'))>0) {
     $OUTPUT->show_message('Forbidden', 'error');
     $OUTPUT->send('iframe');
  }
  else
  {
    $sent = rcmail_deliver_message($MAIL_MIME, $from, $mailto, $smtp_error);
  }


instead of:

PHP:

  $sent = rcmail_deliver_message($MAIL_MIME, $from, $mailto, $smtp_error);

Open source is fine