diff --git a/roles/mail_forwarder/defaults/main.yml b/roles/mail_forwarder/defaults/main.yml
index 50426184d36507fb14078c1d1360e93c1425cdbf..9aff8c79653f0a08fcfe6f90e58a3df916df6f63 100644
--- a/roles/mail_forwarder/defaults/main.yml
+++ b/roles/mail_forwarder/defaults/main.yml
@@ -4,3 +4,4 @@ local_mail_aliases: {}
 smtp_from_relay_allowed: True
 smtp_relay_host: ""
 smtp_relay_truststore: "{{ lookup('file', tls_certificate_dir + '/truststore.pem') }}"
+smtp_relay_host_port: null