An additional feature needs to install first to make Windows 2008 Server as act an Active Directory Domain Controller which is - Active Directory Domain Service Role.
Click on Start - >Programs -> Administrative Tools -> Server Manager
2. Now Select Roles from left pane then click on Add Roles link.
3. Go to Next
4. Check on Active Directory Domain Services box, and click Next
5. Go to Next
6. Hit Install
7. It will look like below while install the role
8. To finish click on Close
9. Open Run by pressing Windows Key and R together and type dcpromo in the Run dialog box and hit on OK
10. Active Directory Domain Service wizard will open, just click Next
11. Proceed to Next
12. Select Create a new domain in a new forest and click Next
13. Input your desired FQDN (Fully Qualified Domain Name) and click Next
It will check the name you have entered is existent in the LAN or not
14. Choose your compatible forest level and click Next
15. Select your desired domain functional level then Next
(If you choose Windows Server 2008 as forest function level, you don’t have to choose a domain function level.)
16. This will examine whether the DNS is configured correctly or not
17. If there is no DNS configured then it will present you to automatic install of DNS in the system. Also note that the first Domain Controller has to be the Global Catalog server
18. Due to IPv6 it will popup a message that the server having one or more dynamic IP address. If you don’t need IPv6 then just overlook the message and click No, I will assign IP addresses to all physical network adapters
19. Next there may be a message regarding DNS delegation if the DNS is not configured, just click Yes
20. Choose your suitable location to store Active Directory database, log files and SYSVOL to achieve full performance. Then Next
21. Give a strong password for AD (Active Directory) Recovery mode. This password is important and you may need it often future, so preserve it on a safe place. Click Next
22. Click on Next
23. Now it will start building Active Directory domain
24. Click on Finish
25. And finally restart the Server
After restart the server you can now create users from Active Directory Users and Computers
Right click on the surface area on right pane, select New then click on User.
