How to Disable IPv6 in Windows Server 2012

Method 1: Regedit

Press the Windows Key and the R key at the same time to bring up the Run dialog box.

Type regedit in the Run dialog box and click OK

Use Registry Editor to expand the registry tree and browse to:
\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters

Right click on Parameters, expand New, and select DWORD (32-bit) Value

Enter DisabledComponents into the Name field

Double click on the new DisabledComponents value, enter ffffffff into the Value data dialog box, and click theOK button

Confirm the new registry value contains the required data.

After restarting the computer, run ipconfig again at the command prompt to confirm that IPv6 is disabled.

ipconfig shows nothing but good old reliable IPv4.

Method 2: Command Prompt

Start a command prompt with administrative permissions and enter the following command:

reg add hklm\system\currentcontrolset\services\tcpip6\parameters /v DisabledComponents /t REG_DWORD /d 0xFFFFFFFF