diff --git a/admin-guide/configuration/configuration_email.md b/admin-guide/configuration/configuration_email.md
index 0e40479e..a4ee8a68 100644
--- a/admin-guide/configuration/configuration_email.md
+++ b/admin-guide/configuration/configuration_email.md
@@ -24,6 +24,12 @@ To enable the possibility to send emails from a machine to one of the standard g
 base::enable_mta: true
 ```
 
+The default name of the sending mail server is the hostname of the machine running postfix. To rename it use `mta::myhostname`.
+
+```yaml
+mta::myhostname: 'foobar.psi.ch'
+```
+
 ## Sending Emails Via An Other SMTP Relay
 
 If your machine is in the default network zone (i.e. PSI intranet) sending via a differnet mail gateway than the default can be done like this: