In a domain network, it is important to have more than one DC so that if one DC fails, the other DC will continue serving the clients. There is also load-balancing of Active Directory Service if we have more than one DC.
                The first DC we create is simply called First DC and if we create an extra DC, then that DC is called ADC. ADC has the same configuration of Active Directory as the First DC.
                  All the DCs in a domain network are Masters. We can make any change in the Active Directory of any DC and that change is replicated to all other DCs. Replication takes place among all the DCs and it is controlled automatically. If we create a user in the First DC, it is automatically created in the ADC because of replication.  
                   All the DCs in the domain network are peers and this model is called Multi-Master Model.


1. Go to a 2003 server computer and configure it as DC with domain name as This will be your First DC.
2.To create ADC, go to another 2003 server computer, in the TCP/IP properties, give DNS address for .If DNS is present in the First DC, just type the ip of First DC in the ‘Preferred DNS server’ box.
3. Click O.K.
4. In the RUN, type:
5. Click O.K.
6. Click next > next.
7. Select ‘Additional domain controller……….’ > next.
8. Type username as Administrator and password of First DC. In the domain, type
9. Click next > Browse > select > O.K. > next.
10. Click next > next > next > next > finish.
11. Now this computer is the ADC.