Solution: To disable "NetBios over TCP/IP" on all interfaces run, login into your Windows 2012 R2 core server and enter the following:
wmic /interactive:off nicconfig where TcpipNetbiosOptions=0 call SetTcpipNetbios 2
This will find NICs which have set the "Use NetBIOS setting from the DHCP server" (=0) and will disable that (=2). The 2nd one below:
wmic /interactive:off nicconfig where TcpipNetbiosOptions=1 call SetTcpipNetbios 2
Will find NICs which have the "Enable NetBIOS over TCP/IP" (=1) set and will disable that (=2) as well.
In most situations the first command should work for you.
inside the CMD box.
To check if it is disabled now enter:
and search for the NetBIOS line(s) which should now look like the following:
NetBIOS over Tcpip. . . . . . . . : Disabled
These commands also work on Windows 2012 R2 (and a newer Microsoft OS) which have a GUI. Run CMD as admin on that server and enter the commands above.
Some applications still might require NetBIOS so please test if you can disable it on your test environment at first!