diff --git a/roles/smtpgateway/tasks/main.yaml b/roles/smtpgateway/tasks/main.yaml
index e36a092..e1d452c 100644
--- a/roles/smtpgateway/tasks/main.yaml
+++ b/roles/smtpgateway/tasks/main.yaml
@@ -17,6 +17,9 @@
     src: templates/main.cf
     dest: /etc/postfix/main.cf
 
+- name: Build /etc/mailname
+  command: hostname --fqdn > /etc/mailname
+
 - name: Build hashtable of SASL creds
   command: postmap /etc/postfix/sasl_passwd