diff --git a/README.rst b/README.rst
index 7acd1e7..dd8424e 100644
--- a/README.rst
+++ b/README.rst
@@ -32,7 +32,7 @@ Usage::
   $ sudo python3 run.py <your domain>
 
 
-If ``python3`` if not installed on your system, please install it.
+If ``python3`` is not installed on your system, please install it.
 
 A configuration file will be automatically generated the first time
 you run the installer, please don't copy the
diff --git a/modoboa_installer/scripts/automx.py b/modoboa_installer/scripts/automx.py
index 6564e7b..b086e9e 100644
--- a/modoboa_installer/scripts/automx.py
+++ b/modoboa_installer/scripts/automx.py
@@ -34,7 +34,7 @@ class Automx(base.Installer):
         """Additional variables."""
         context = super(Automx, self).get_template_context()
         sql_dsn = "{}://{}:{}@{}/{}".format(
-            self.dbengine,
+            "postgresql" if self.dbengine == "postgres" else self.dbengine,
             self.config.get("modoboa", "dbuser"),
             self.config.get("modoboa", "dbpassword"),
             self.dbhost,
diff --git a/modoboa_installer/scripts/files/postfix/main.cf.tpl b/modoboa_installer/scripts/files/postfix/main.cf.tpl
index 6b83357..7af5487 100644
--- a/modoboa_installer/scripts/files/postfix/main.cf.tpl
+++ b/modoboa_installer/scripts/files/postfix/main.cf.tpl
@@ -1,5 +1,5 @@
 inet_interfaces = all
-inet_protocols = ipv4
+inet_protocols = all
 myhostname = %hostname
 myorigin = $myhostname
 mydestination = $myhostname