diff --git a/doc/integration/imap_and_smtp.rst b/doc/integration/imap_and_smtp.rst
index c8a0d9800..520909faf 100644
--- a/doc/integration/imap_and_smtp.rst
+++ b/doc/integration/imap_and_smtp.rst
@@ -502,6 +502,7 @@ Use the following configuration in the :file:`/etc/postfix/main.cf` file
         ...
         check_recipient_access <driver>:/etc/postfix/sql-maintain.cf
         permit_mynetworks
+        reject_unverified_recipient
         ...
 
   # Stuff after