diff --git a/templates/main.cf.j2 b/templates/main.cf.j2
index 3289561..0c443e3 100644
--- a/templates/main.cf.j2
+++ b/templates/main.cf.j2
@@ -50,3 +50,8 @@ smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
 sender_dependent_relayhost_maps = hash:/etc/postfix/sender_relay
 smtp_sender_dependent_authentication = yes
 {% endif %}
+
+{% if postfix_transport_maps is defined %}
+transport_maps = hash:/etc/postfix/transport
+smtp_sender_dependent_authentication = yes
+{% endif %}