Certbot: HSTS Preloading

certbot.md

@@ -114,8 +114,12 @@ filename: `/etc/nginx/snippets/ssl/example.com.conf`
 ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
 ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
 
-# Replace with the domain's HSTS policy
+# Normal HSTS policy. Remove if you use preload one.
 add_header Strict-Transport-Security "max-age=63072000" always;
+
+# This forces your domain's all subdomains to HTTPS.
+# Please submit to your domain to https://hstspreload.org/ if you select this option.
+#add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;
 ```
 
 ## SSL params