Please note that The Microsoft Loopback Adapter was renamed in Windows Server 2012/2012R2. The new name is "Microsoft KM-TEST Loopback Adapter".
To launch the Add-Hardware wizard please open an elevated cmd or powershellconsole and type the following command:
This will launch either the Add-Hardware wizard or Device Manager. If the Add-Hardware wizard comes up, please skip the part related to Device Manager.
If Device Manager comes up, right-click on the computer name at the top of the hardware tree and choose "Add Legacy Hardware" from the pop up context menu.
The Add-Hardware wizard comes up.
Click Next and choose "Install the hardware that I manually select from a list (Advanced)" in the "What do you want the wizard to do?" dialog and click next again.
In the hardware list choose Network Adapters and click next.
In the "Select Network Adapter List" select "Microsoft" in the Manufacturer pane and "Microsoft KM-TEST Loopback Adapter" in the network adapter pane.
Click Next and next again to install the loopback adapter and click finish when it is done.
Close the wizard and device manager
C:\> control ncpa.cpl
The Network Connections dialog opens up. Make sure that the LoopBack Adaper is installed.
Configure it with the desired IP values.
You are all set now and can continue troubleshooting.