diff --git a/postfix-relay/templates/main.cf.j2 b/postfix-relay/templates/main.cf.j2
index a95cfb2..a27e497 100644
--- a/postfix-relay/templates/main.cf.j2
+++ b/postfix-relay/templates/main.cf.j2
@@ -63,6 +63,9 @@ smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
 smtp_sasl_security_options = {{ postfix_smtp_sasl_security_options }}
 smtp_sasl_tls_security_options = {{ postfix_smtp_sasl_tls_security_options }}
 smtp_sasl_mechanism_filter = {{ postfix_smtp_sasl_mechanism_filter }}
+{% if ansible_distribution_major_version >= '18' %}
+smtpd_relay_restrictions = permit_sasl_authenticated, reject
+{% endif %}
 {% endif %}
 {% if postfix_relay_server %}
 smtpd_sasl_path = smtpd