Before installing Active Directory in Windows Server 2012 R2, the ipconfig /all command should have nothing listed in Primary Dns Suffix.

C:\Users\Administrator> ipconfig /all
Host Name  . . . . . . : WinSrv2012R2
Primary Dns Suffix . . :

To install Active Directory Domain Services (AD DS):

C:\Users\Administrator> powershell
PS C:\Users\Administrator> Add-WindowsFeature AD-Domain-Services

Success Restart Needed Exit Code    Feature Result
------- -------------- ---------    --------------
True    No             Success      <Active Directory Domain Services>

Promote the server to a Domain Controller (DC). SafeModeAdministratorPassword is the same password that is used to sign into Windows Server 2012 as an administrator. There may be a series of warnings. Ignore the warnings for now. Eventually, message operation completed successfully should be displayed, and you will be prompted that the machine will restart. After the machine has restarted, at the sign in screen, your new domain name should proceed your username, such as EXAMPLE\\Administrator. Sign into Windows Server 2012.

PS C:\Users\Administrator> Install-ADDSForest -DomainName "example.local"
SafeModeAdministratorPassword: ***********
ConfirmSafeModeAdministratorPassword: ***********

The target server will be configured as a domain controller and restart when this operation is complete
Y

After restart, the ipconfig /all command will display the Primary Dns Suffix.

C:\Users\Administrator> ipconfig /all
Host Name  . . . . . . : WinSrv2012R2
Primary Dns Suffix . . : example.local

You can also start PowerShell and use the Get-ADDomain to view information about the domain. In the example, the name of the Domain Controller is example.

C:\Users\Administrator> powershell
PS C:\Users\Administrator> Get-ADDomain
. . .
DistingushedName     : DC=example