diff --git a/lib/logstash/codecs/leef.rb b/lib/logstash/codecs/leef.rb
index af57ea5..b46d430 100644
--- a/lib/logstash/codecs/leef.rb
+++ b/lib/logstash/codecs/leef.rb
@@ -12,7 +12,7 @@ class LogStash::Codecs::LEEF < LogStash::Codecs::Base
   config_name "leef"
   
   # Field is to disable the leef header, which can be helpful for generating WCollect messages over syslog
-  config :leefheader, :validate => boolean, :default => true
+  config :leefheader, :validate => :boolean, :default => true
 
   # Field to enable the default syslog header, which uses the default `%{host}` field for hostname and the timestamp is generated by the codec parsing time. If no value is set the hostname is set to the `hostname` value where logstash is running.
   config :syslogheader, :validate => :boolean, :default => true