diff --git a/manifests/named_vhost.pp b/manifests/named_vhost.pp
index 64a060b5b90e617a0b9c1b2fce92dee9331e1db2..87589777e7922d649286d3985d50840a30419a6f 100644
--- a/manifests/named_vhost.pp
+++ b/manifests/named_vhost.pp
@@ -61,6 +61,9 @@ define apache::named_vhost($urls,
     case $ensure
     {
 	'present': {
+	    if ($config == undef  or  $config == false) {
+		fail("Apache::Named_vhost[${title}]: Config not specified")
+	    }
 	    if $certname {
 		include x509certs
 	    }