Rocks Cluster : untrusted X11 Warning Message when SSH X11 compute Nodes

When we login ssh with X11 from rocks  master node to computer node it doesn't allow X11 to forward as :

$ ssh node10 -X
Warning: untrusted X11 forwarding setup failed: xauth key data not generated
Warning: No xauth data; using fake authentication data for X11 forwarding.
Last login: Tue Dec 17 20:34:52 2013 from test.rocks.com
Rocks Compute Node
Rocks 6.1 (Emerald Boa)
Profile built 14:32 21-Nov-2013

For that In Rocks Master node edit /etc/ssh/ssh_config add following line :

        ForwardX11Trusted       yes