@alomarh Well it depends on what version of linux you are using. This appears to be RHEL compatible OS.
You can restrict the NFS server in FOG to limit access to a specific subnet range. You can do this without the need of a firewall. Look at the /etc/exports file. In the share line it starts with a star ( * ) replace that with the subnet range you want to share to. Look up nfs and exports for the exact syntax. Its hard to limit NFS to a single port range. You can do it, but you will need to make some configuration changes. NFSv4 is the way to go, but FOG is not there yet. I did experiment with it and it works with a few changes to the FOG server and FOS Linux.
