diff --git a/build/run/installer.sh b/build/run/installer.sh
index 53db8f6..9e1a921 100755
--- a/build/run/installer.sh
+++ b/build/run/installer.sh
@@ -100,7 +100,7 @@ postconf -e 'non_smtpd_milters = $smtpd_milters'
 
 # Blocking spam
 # postconf -e "smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unknown_sender_domain, reject_unknown_reverse_client_hostname, reject_unknown_client_hostname"
-postconf -e "smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unknown_sender_domain, reject_unknown_client_hostname"
+postconf -e "smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unknown_sender_domain, reject_unknown_reverse_client_hostname"
 postconf -e "smtpd_helo_required = yes"
 postconf -e "smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, check_helo_access lmdb:/etc/postfix/helo_access, reject_invalid_helo_hostname, reject_non_fqdn_helo_hostname, reject_unknown_helo_hostname"