Postfix user sender resctriction

Hello all !

Today we want to restrict local user to send mail to more destinations!

1 First step

postconf -e 'smtpd_recipient_restrictions = check_sender_access hash:/etc/postfix/restricted_senders'
postconf -e 'smtpd_restriction_classes = local_only'
postconf -e 'local_only = check_recipient_access hash:/etc/postfix/local_domains, reject'

2. Step 2 Then create the file /etc/postfix/restricted_senders which looks similar to this one:        local_only       local_only

3. Final step Afterwards create /etc/postfix/local_domains which should look similar to this:                  OK                 OK             OK

After this restart your server postfix! Enjoy!
(Source Thanks falko )