diff --git a/README.rst b/README.rst
index 18865a1..73d5df0 100644
--- a/README.rst
+++ b/README.rst
@@ -1,7 +1,7 @@
 modoboa-installer
 =================
 
-An installer for Modoboa.
+An installer which deploy a complete mail server based on Modoboa.
 
 .. warning::
 
@@ -12,7 +12,7 @@ Usage::
 
   $ git clone https://github.com/modoboa/modoboa-installer
   $ cd modoboa-installer
-  $ sudo ./run.py
+  $ sudo ./run.py <mail server hostname>
 
 To customize the installation, look at the ``installer.cfg`` file.
 
diff --git a/modoboa_installer/scripts/files/postfix/main.cf.tpl b/modoboa_installer/scripts/files/postfix/main.cf.tpl
index 5420598..0bd76a3 100644
--- a/modoboa_installer/scripts/files/postfix/main.cf.tpl
+++ b/modoboa_installer/scripts/files/postfix/main.cf.tpl
@@ -86,6 +86,10 @@ strict_rfc821_envelopes = yes
 %{dovecot_enabled}    $lmtp_sasl_auth_cache_name
 %{dovecot_enabled}    $address_verify_map
 
+smtpd_sender_login_maps =
+        %{db_driver}:/etc/postfix/sql-sender-login-mailboxes.cf
+        %{db_driver}:/etc/postfix/sql-sender-login-aliases.cf
+
 # Recipient restriction rules
 smtpd_recipient_restrictions =
       permit_mynetworks
diff --git a/modoboa_installer/scripts/files/postfix/master.cf.tpl b/modoboa_installer/scripts/files/postfix/master.cf.tpl
index 281bc93..466a80c 100644
--- a/modoboa_installer/scripts/files/postfix/master.cf.tpl
+++ b/modoboa_installer/scripts/files/postfix/master.cf.tpl
@@ -23,7 +23,7 @@ submission inet n       -       -       -       -       smtpd
   -o smtpd_reject_unlisted_recipient=no
   -o smtpd_client_restrictions=permit_sasl_authenticated,reject
   -o smtpd_helo_restrictions=
-  -o smtpd_sender_restrictions=
+  -o smtpd_sender_restrictions=reject_sender_login_mismatch
   -o smtpd_recipient_restrictions=
   -o milter_macro_daemon_name=ORIGINATING
   -o smtpd_proxy_filter=inet:[127.0.0.1]:10026