Data node loss connection‏ (no replies)

Hi everybody,

I have a situation that the data node keep losing the connection form the Management nodes.
My setup is 2x management node, 2x data nodes, 2x SQL nodes, each node is using a different host
The Management nodes starts up correctlly. when I startup the data nodes, and run the "SHOW" command on the Management clients, it shows that data node are connected and after few seconds when I run the "SHOW" command again, one of the data nodes Loss the connection with the cluster.
I checked the firewall on each node and I verified that it was disabled.
so how can I troubleshoot this problem?
Thank you in advance