diff --git a/ntpd/manifests/init.pp b/ntpd/manifests/init.pp
index a5b8096..a48a792 100644
--- a/ntpd/manifests/init.pp
+++ b/ntpd/manifests/init.pp
@@ -3,7 +3,8 @@
 # === Global variables
 #
 #   $ntp_server:
-#       Array of NTP servers.
+#       Array of NTP servers using [] will disable external servers.
+#       Defaults to pool.ntp.org.
 #
 #   $ntp_client_networks:
 #       Array of networks that are allowed to query this server in format