add warning about removing front

docs/reverse.rst

@@ -225,6 +225,6 @@ You can also download the example configuration files:
 Disable completely Mailu reverse proxy
 --------------------------------------
 
-You can simply disable Mailu reverse proxy by removing the ``front`` section from the ``docker-compose.yml`` and use your own means to reverse proxy requests to the proper containers.
+You must not disable Mailu reverse proxy by removing the ``front`` section from the ``docker-compose.yml``.
 
-Be careful with this method as resolving container addresses outside the Docker Compose structure is a tricky task: there is no guarantee that addresses will remain after a restart and you are almost certain that addresses will change after every upgrade (and whenever containers are recreated).
+``front`` is handling authentication and is also proxying e.g. SMTP and IMAP. A basic HTTP reverse proxy as described in this document is not sufficient for this.