On a fresh install of Windows Server 2012R2, not joined to a domain, the first network connection (obtained through DHCP) is always treated as a Public network. Normally, when joining a domain, the network connection then becomes a Domain network, but if the server will not be joined to a domain, you probably will want to set it to Private. Unfortunately, the Public Network link in Network Center is not clickable, and thus, cannot be changed. But you can make the change anyway through the Local Security Policy.

Through Powershell (preferred method):

1. Look up the name of the network interface (e.g. "Local Area Connection") in the network adapters list.
2. Open an elevated Powershell and run the following cmdlets, replacing NicName with the name you looked up in the previous step:

   $NCP = Get-NetConnectionProfile -InterfaceAlias "Local Area Connection"
   $NCP.NetworkCategory = "Private"
   Set-NetConnectionProfile -InputObject $NCP

   The change is effective immediately.

Through Group Policy (not preferred)

1. Open Local Security Policy (Start → Run → secpol.msc
2. Under Security Settings, click Network List Manager Policies.
3. Look for the entry corresponding with your network (usually this is called Network), and open its properties (double-click).
4. On the Network Location tab, set the Location type to Private.
5. Click OK to save changes and close Local Security Policy. The change is effective immediately.