Set access control within LAN

I use the WD My Cloud Mirror in a small office LAN. I found that if I put this NAS in the LAN, everyone in the LAN can view/edit the contents of the shared files. e.g. if I set the host name of the NAS as mynas, in other Windows workstation, I just type \mynas, then I can connect to the shared folder.

I tried to set up user privileges as shown in the manual, but without any luck, any users in the same LAN can gain access to the share folders.

I’m just wondering if there any way to set up proper access control on this NAS within LAN.  

P.S. I don’t use it as a cloud device, I just use it as a NAS in LAN.

Million thanks in advance.

They should be able to see it but they wouldn’t be able to open up the Public folder…unless those users have been setup as users on the NAS, which I’m assuming they have not been. Public folder (by default) allows access to any NAS user but does not allow anonymous access.

Furthermore, the NAS’ registered users can be blocked from accessing individually from the dashboard’s Shares tab by clicking on the Public folder and setting its access permissions.