diff --git a/roles/postfix_non_mailhost/templates/main.cf.j2 b/roles/postfix_non_mailhost/templates/main.cf.j2
index 5b90030..d5f5166 100644
--- a/roles/postfix_non_mailhost/templates/main.cf.j2
+++ b/roles/postfix_non_mailhost/templates/main.cf.j2
@@ -20,6 +20,7 @@ compatibility_level = 2
 # Send mail as user@{{ ansible_fqdn }}
 myhostname = {{ ansible_fqdn }}
 myorigin = $myhostname
+mydomain = $myhostname
 
 # Specify the trusted networks
 mynetworks = 127.0.0.0/8 {{ local_network }}