diff --git a/states/postfix/defaults.yaml b/states/postfix/defaults.yaml
index 4232de6..66a52e2 100644
--- a/states/postfix/defaults.yaml
+++ b/states/postfix/defaults.yaml
@@ -23,7 +23,8 @@ postfix:
         - 'localhost'
       mydomain: 'example.com'
       myhostname: 'mx.example.com'
-      mynetworks: '127.0.0.1'
+      mynetworks:
+        - '127.0.0.1'
       myorigin: '$mydomain'
       non_smtpd_milters: '$smtpd_milters'
       readme_directory: 'no'
@@ -47,4 +48,4 @@ postfix:
     master: {}
     sender_access: {}
     transport: {}
-    pgsql: {}
+    pgsql: {}
\ No newline at end of file