diff --git a/ntpd/manifests/init.pp b/ntpd/manifests/init.pp
index a48a792..8aeee0a 100644
--- a/ntpd/manifests/init.pp
+++ b/ntpd/manifests/init.pp
@@ -8,7 +8,8 @@
 #
 #   $ntp_client_networks:
 #       Array of networks that are allowed to query this server in format
-#       [ "192.168.1.0/255.255.255.0", "192.168.2.0/255.255.255.0", ].
+#       [ "192.168.1.0/255.255.255.0", "192.168.2.0/255.255.255.0", ] or
+#       [ "2001:838:0:1::/ffff:ffff:ffff:ffff::" ] for IPv6.
 #
 class ntpd {