diff --git a/manifests/init.pp b/manifests/init.pp
index c9de9a4c8..b7358d998 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -60,7 +60,7 @@
 
   ### START Nginx Configuration ###
   Optional[Enum['on', 'off']] $absolute_redirect             = undef,
-  $accept_mutex                                              = 'on',
+  Enum['on', 'off'] $accept_mutex                            = 'on',
   $accept_mutex_delay                                        = '500ms',
   $client_body_buffer_size                                   = '128k',
   String $client_max_body_size                               = '10m',
@@ -76,7 +76,7 @@
   String $fastcgi_cache_max_size                             = '500m',
   Optional[String] $fastcgi_cache_path                       = undef,
   Optional[String] $fastcgi_cache_use_stale                  = undef,
-  $gzip                                                      = 'on',
+  Enum['on', 'off'] $gzip                                    = 'on',
   $gzip_buffers                                              = undef,
   $gzip_comp_level                                           = 1,
   $gzip_disable                                              = 'msie6',
@@ -84,13 +84,13 @@
   $gzip_http_version                                         = 1.1,
   $gzip_proxied                                              = 'off',
   $gzip_types                                                = undef,
-  $gzip_vary                                                 = 'off',
+  Enum['on', 'off'] $gzip_vary                               = 'off',
   Optional[Variant[Hash, Array]] $http_cfg_prepend           = undef,
   Optional[Variant[Hash, Array]] $http_cfg_append            = undef,
   Optional[Variant[Array[String], String]] $http_raw_prepend = undef,
   Optional[Variant[Array[String], String]] $http_raw_append  = undef,
-  $http_tcp_nodelay                                          = 'on',
-  $http_tcp_nopush                                           = 'off',
+  Enum['on', 'off'] $http_tcp_nodelay                        = 'on',
+  Enum['on', 'off'] $http_tcp_nopush                         = 'off',
   $keepalive_timeout                                         = '65s',
   $keepalive_requests                                        = '100',
   $log_format                                                = {},
@@ -126,11 +126,11 @@
   Array $proxy_hide_header                                   = [],
   Array $proxy_pass_header                                   = [],
   Array $proxy_ignore_header                                 = [],
-  $sendfile                                                  = 'on',
-  String $server_tokens                                      = 'on',
-  $spdy                                                      = 'off',
-  $http2                                                     = 'off',
-  $ssl_stapling                                              = 'off',
+  Enum['on', 'off'] $sendfile                                = 'on',
+  Enum['on', 'off'] $server_tokens                           = 'on',
+  Enum['on', 'off'] $spdy                                    = 'off',
+  Enum['on', 'off'] $http2                                   = 'off',
+  Enum['on', 'off'] $ssl_stapling                            = 'off',
   $types_hash_bucket_size                                    = '512',
   $types_hash_max_size                                       = '1024',
   Integer $worker_connections                                = 1024,
@@ -146,7 +146,7 @@
   $package_name                                              = $nginx::params::package_name,
   $package_source                                            = 'nginx',
   $package_flavor                                            = undef,
-  $manage_repo                                               = $nginx::params::manage_repo,
+  Boolean $manage_repo                                       = $nginx::params::manage_repo,
   Hash[String[1], String[1]] $mime_types                     = $nginx::params::mime_types,
   Optional[String] $repo_release                             = undef,
   $passenger_package_ensure                                  = 'present',
diff --git a/manifests/resource/server.pp b/manifests/resource/server.pp
index 1ae123aab..fda031cc4 100644
--- a/manifests/resource/server.pp
+++ b/manifests/resource/server.pp
@@ -156,7 +156,7 @@
   Variant[Array, String] $ipv6_listen_ip                                         = '::',
   Integer $ipv6_listen_port                                                      = 80,
   String $ipv6_listen_options                                                    = 'default ipv6only=on',
-  Optional[Hash] $add_header                                                     = undef,
+  Hash $add_header                                                               = {},
   Boolean $ssl                                                                   = false,
   Boolean $ssl_listen_option                                                     = true,
   Optional[Variant[String, Boolean]] $ssl_cert                                   = undef,
@@ -183,8 +183,8 @@
   Optional[String] $ssl_session_ticket_key                                       = undef,
   Optional[String] $ssl_trusted_cert                                             = undef,
   Optional[Integer] $ssl_verify_depth                                            = undef,
-  String $spdy                                                                   = $nginx::spdy,
-  $http2                                                                         = $nginx::http2,
+  Enum['on', 'off'] $spdy                                                        = $nginx::spdy,
+  Enum['on', 'off'] $http2                                                       = $nginx::http2,
   Optional[String] $proxy                                                        = undef,
   Optional[String]$proxy_redirect                                                = undef,
   String $proxy_read_timeout                                                     = $nginx::proxy_read_timeout,
diff --git a/spec/classes/nginx_spec.rb b/spec/classes/nginx_spec.rb
index 24e0e3838..7b017ea80 100644
--- a/spec/classes/nginx_spec.rb
+++ b/spec/classes/nginx_spec.rb
@@ -570,7 +570,7 @@
               {
                 title: 'should not set sendfile',
                 attr: 'sendfile',
-                value: false,
+                value: 'off',
                 notmatch: %r{sendfile}
               },
               {