diff --git a/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf b/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
index 55f0899af69bf44a3b32895dbbd9ec980a0efbac..809cf204d03e30945bfc1db29731bbf897a01e8f 100644
--- a/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
+++ b/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
@@ -13,3 +13,4 @@ transport_maps = regexp:/opt/mailman/postfix_lmtp \lmdb:/etc/postfix/transport.m
 local_recipient_maps = regexp:/opt/mailman/postfix_lmtp
 always_add_missing_headers = yes
 local_header_rewrite_clients = permit_sasl_authenticated
+relay_domains = regexp:/opt/mailman/postfix_domains \${podop}transport