diff --git a/manifests/classes/postfix.pp b/manifests/classes/postfix.pp
index 7f9e91c..aa04cfc 100644
--- a/manifests/classes/postfix.pp
+++ b/manifests/classes/postfix.pp
@@ -40,7 +40,21 @@ class postfix {
   case $root_mail_recipient {
     "":   { $root_mail_recipient = "nobody" }
   }
-
+  case $postfix_use_amavisd {
+    "":   { $postfix_use_amavisd = "no" }
+  }
+  case $postfix_use_dovecot_lda {
+    "":   { $postfix_use_dovecot_lda = "no" }
+  }
+  case $postfix_use_schleuder {
+    "":   { $postfix_use_schleuder = "no" }
+  }
+  case $postfix_use_sympa {
+    "":   { $postfix_use_sympa = "no" }
+  }
+  case $postfix_mastercf_tail {
+    "":   { $postfix_mastercf_tail = "" }
+  }
 
   package { ["postfix", "mailx"]:
     ensure => installed