diff --git a/src/sunstone/etc/sunstone-server.conf b/src/sunstone/etc/sunstone-server.conf
index ce090a1002..a54be01c1c 100644
--- a/src/sunstone/etc/sunstone-server.conf
+++ b/src/sunstone/etc/sunstone-server.conf
@@ -148,6 +148,8 @@
 # :vnc_request_password: true | false
 #   Request VNC password for external windows, by default it will not be requested
 #
+# :allow_vnc_federation: yes | no
+#   Allow VNC functionality in remote OpenNebula in a federation (needs special setup)
 :vnc_proxy_port: 29876
 :vnc_proxy_support_wss: no
 :vnc_proxy_cert: