diff --git a/emailwiz.sh b/emailwiz.sh
old mode 100755
new mode 100644
index 69fe185..64a64e4
--- a/emailwiz.sh
+++ b/emailwiz.sh
@@ -94,6 +94,7 @@ postconf -e 'smtpd_sasl_type = dovecot'
 postconf -e 'smtpd_sasl_path = private/auth'
 
 # Sender, relay and recipient restrictions
+postconf -e "smtpd_sender_login_maps = pcre:/etc/postfix/login_maps.pcre"
 postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, reject_unknown_recipient_domain'
 postconf -e 'smtpd_relay_restrictions = permit_sasl_authenticated, reject_unauth_destination'
 
@@ -107,6 +108,10 @@ postconf -e 'home_mailbox = Mail/Inbox/'
 # Prevent "Received From:" header in sent emails in order to prevent leakage of public ip addresses
 postconf -e "header_checks = regexp:/etc/postfix/header_checks"
 
+# Create a login map file that ensures that if a sender wants to send a mail from a user at our local
+# domain, they must be authenticated as that user
+echo "/^(.*)@$(sh -c "echo $domain | sed 's/\./\\\./'")$/   \${1}" > /etc/postfix/login_maps.pcre
+
 # strips "Received From:" in sent emails
 echo "/^Received:.*/     IGNORE
 /^X-Originating-IP:/    IGNORE" >> /etc/postfix/header_checks