This issue relates to a home lab enviroment.
I have presented my NAS box externally to the internet.
My issue is that that my NFS shares for ESXi have the 'everyone' full access so they are visible to all users connecting externally to my nas box.
If I take the 'everyone' off my esxi server loses access to the shares, I have tried all three options available on the NAS box in regards to the NFS protocol settings as attached in the screenshot.
I assume this has something to do with the no_root_squash config, I thought about creating a user account called 'root' on the NAS box with the same password as the root account on the ESXi server but of course the NAS is Linux and already has a root account by default.....
How can I isolate these ESXi NFS shares so that they are only visible to my ESXi servers?
I have figured this out, just needed to be a little more vigalent.
For anyone else suffering with this type of problem it was solved by doing this.
On the NFS share configuration page on the NAS box there is a section called 'NFS' where you can add an 'NFS Rule'.
So you basically disable the Access Permissions for 'everyone' and then create a rule that allows a subnet or IP address that your ESX uses for the iSCSI/NFS network.
Badda Bing, .......... Boom