diff --git a/data/conf/postfix/main.cf b/data/conf/postfix/main.cf
index e8da7947..840042c3 100644
--- a/data/conf/postfix/main.cf
+++ b/data/conf/postfix/main.cf
@@ -195,6 +195,7 @@ smtpd_last_auth = check_policy_service inet:127.0.0.1:10028
 # Define protocols for SMTPS and submission service
 submission_smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
 smtps_smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
+parent_domain_matches_subdomains = debug_peer_list,fast_flush_domains,mynetworks,qmqpd_authorized_clients
 
 # DO NOT EDIT ANYTHING BELOW #
 # User overrides #