diff --git a/admin_manual/configuration/configuration_mail.rst b/admin_manual/configuration/configuration_mail.rst
index 073fd5729..b8b124e14 100644
--- a/admin_manual/configuration/configuration_mail.rst
+++ b/admin_manual/configuration/configuration_mail.rst
@@ -361,11 +361,11 @@ hurry, you can use the ``netstat`` command. This example shows all active
 servers on your system, and the ports they are listening on. The SMTP server is 
 listening on localhost port 25:
 
-::
+.. code-block::
 
 # netstat -pant
 
-::
+.. code-block::
 
 Active Internet connections (servers and established)
 Proto Recv-Q Send-Q Local Address   Foreign Address  State  ID/Program name