diff --git a/mailman-extra.cfg.tmpl b/mailman-extra.cfg.tmpl
index c497489..2d7ab06 100644
--- a/mailman-extra.cfg.tmpl
+++ b/mailman-extra.cfg.tmpl
@@ -7,8 +7,8 @@ lmtp_host: {{ env "MAILMAN_HOSTNAME" }}
 lmtp_port: 8024
 
 # Postfix server's hostname or IP from mailman-core
-smtp_host: smtp.example.com
-smtp_port: 25
+smtp_host: {{ env "CORE_SMTP_HOSTNAME" }}
+smtp_port: {{ env "CORE_SMTP_PORT" }}
 configuration: /etc/postfix-mailman.cfg
 
 [mailman]