diff --git a/manifests/home_server.pp b/manifests/home_server.pp
index eacd169bc804c81858a015a5a06fc7bf0cb12287..59b2e7b881a081667de224b0c635214ed240e65f 100644
--- a/manifests/home_server.pp
+++ b/manifests/home_server.pp
@@ -2,9 +2,9 @@
 define freeradius::home_server (
   $secret,
   $type = 'auth',
-  $ipaddr = '',
-  $ipv6addr = '',
-  $virtual_server = '',
+  $ipaddr = undef,
+  $ipv6addr = undef,
+  $virtual_server = undef,
   $port = 1812,
   $proto = 'udp',
   $status_check = undef,
diff --git a/manifests/home_server_pool.pp b/manifests/home_server_pool.pp
index e680ec014eb6442c6cb93c86458765cf6c21a427..471024e7a0eb81bf9e9064547935f67debc79a97 100644
--- a/manifests/home_server_pool.pp
+++ b/manifests/home_server_pool.pp
@@ -2,8 +2,8 @@
 define freeradius::home_server_pool (
   $home_server,
   $type = 'fail-over',
-  $virtual_server = '',
-  $fallback = '',
+  $virtual_server = undef,
+  $fallback = undef,
 ) {
   $fr_basepath = $::freeradius::params::fr_basepath
 
diff --git a/manifests/init.pp b/manifests/init.pp
index 0d658933c4dbe52db8fde6e89ca17ed4a4800254..21c007e17c3db3bc94c34dc9a7f2075eebdbd7ef 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -270,7 +270,7 @@ class freeradius (
   # package to be sure that the group has been created.
   group { $freeradius::fr_group:
     ensure  => present,
-    require => Package[$freeradius::fr_package]
+    require => Package[$freeradius::fr_package],
   }
 
   # Syslog rules
diff --git a/manifests/module/huntgroup.pp b/manifests/module/huntgroup.pp
index b4f4c28b39693cb8d172cc7c61ef5cbae80fbd15..668a8bc0bebec3a43b337bf9a72d14e9fcac9f35 100644
--- a/manifests/module/huntgroup.pp
+++ b/manifests/module/huntgroup.pp
@@ -8,6 +8,6 @@ define freeradius::module::huntgroup (
   concat::fragment {"Huntgroup ${name}":
     target  => $huntgroup,
     order   => $order,
-    content => template('freeradius/huntgroup.erb')
+    content => template('freeradius/huntgroup.erb'),
   }
 }
diff --git a/manifests/realm.pp b/manifests/realm.pp
index ec67cb49df1c3076ae987dadef2aa556b2d3b121..e4ec3a7e77fc917a2d65b227c1ade28cd537a06d 100644
--- a/manifests/realm.pp
+++ b/manifests/realm.pp
@@ -1,9 +1,9 @@
 # Set up proxy realms
 define freeradius::realm (
-  $virtual_server = '',
-  $auth_pool = '',
-  $acct_pool = '',
-  $pool = '',
+  $virtual_server = undef,
+  $auth_pool = undef,
+  $acct_pool = undef,
+  $pool = undef,
   $nostrip = false,
 ) {
   $fr_basepath = $::freeradius::params::fr_basepath
diff --git a/manifests/sql.pp b/manifests/sql.pp
index 6a94e0a25af9d6e69a6d7515982545f648724c99..dcaeb97d44a544d9cff9c02aba8a023fa54630a8 100644
--- a/manifests/sql.pp
+++ b/manifests/sql.pp
@@ -7,7 +7,7 @@ define freeradius::sql (
   $radius_db                   = 'radius',
   $num_sql_socks               = '${thread[pool].max_servers}',
   $query_file                  = "\${modconfdir}/\${.:name}/main/\${dialect}/queries.conf",
-  $custom_query_file           = '',
+  $custom_query_file           = undef,
   $lifetime                    = '0',
   $max_queries                 = '0',
   $ensure                      = present,