diff --git a/conf/main.cf b/conf/main.cf
index ab4c7c6..9dbb288 100755
--- a/conf/main.cf
+++ b/conf/main.cf
@@ -52,7 +52,12 @@ smtpd_recipient_restrictions =
    permit_mynetworks,
    permit
 
+# Relay restrictions
+smtpd_relay_restrictions = 
+   permit_mynetworks,
+   reject
+
 ###############
 # Extra Settings
 ###############
-maillog_file = /dev/stdout
\ No newline at end of file
+maillog_file = /dev/stdout