My primary domain controller is a Windows Server 2012
with a static IP address : 192.168.150.12
Its Forest Functional Level and Domain Functional Level
are displayed in the below snapshots :


To setup an additional domain controller, you will need
a new server. This can be either a physical or a virtual
server. Follow the below steps to set up an
additional domain controller for an existing domain
controller :
-
Configure the server's network
card properties to be a static IP address from the
same subnet or subnet which is routable within a
network. As directory services rely on DNS server,
you need to properly point where the service is
running.

-
Join the server to the domain.
So first it will be a domain member, once it is a
domain member like any other station in the network,
then we can promote it and configure it and an
additional Domain Controller.

-
Logon to the server with a
username that has an administrative roles in Active
Directory

-
Open Server Manager
and click on Add roles and features


-
The wizard will
open, showing you the Before you begin
page, click Next to continue

-
Select Role-based or feature-based
installation as
we will be installing a role on a single
server, click Next

-
As this is a local
installation, the server will be listed
and selected automatically from the
server pool. Click Next

-
From the list of
roles, select Active Directory Domain
Services

-
The required
features for AD DS will be automatically
selected , click Add Features

You will be back to the roles page,
click Next to proceed to the features
page
-
On the features
page, all installed features and
required features by AD DS will be
selected. Click Next to continue

-
The main role you
selected to install will have a brief
information about it. Click Next

-
Confirm installation
by reviewing what settings you have
chosen. Select Restart destination
server automatically so that
the server reboot once it completes
installation of the roles and features
if required.


Click Install
-
Once installation is
completed, another step is required.
Promoting this server to a domain
controller


When role is installed,
You will notice a yellow exclamation
mark on the dash board in server manager.
It tells you that post deployment
configuration steps are required
Click on Promote
this server to a domain controller

-
On the Deployment
configuration page, select
Add a domain controller to an existing
domain
The domain name
The logged in user will be displayed, if
you need to select another user with
administrative rights on the domain,
then click Change and select the
preferred user.
Then click Next

-
On the Domain
Controller settings page, specify if
this DC will be a DNS server as well and
if it will be a Global Catalog or not.
It is deffinitly recommended that the
additional domain controller is setup as
a DS & a GC as well. Unless you have
dedicated DNS Services installed on
another servers.
If this is a remote site and you don't
have IT staff in it, or you don't want
anyone to commit any changes to your
Domain Controllers, then select the
checkbox Read only domain controller
(RODC).
If you only have a single site then it
will be displayed by default, if you
have multiple site names, then using the
drop down list select the preferred site
Type a password for directory services
restore mode and confirm it
then click Next

-
Safely ignore the
warning regarding DNS delegation, as
this server is not yet a DNS server .Click
Next

-
Select the source DC to
replicate from.
You can define if you want to install
this Domain Controller from Install From
Media (IFM) ,if you have it, and point
from which DC replication should be
done. When you do not specify, server
will choose the best location for AD
database replication. If you have no
special requirements for that, keep the
default setting as : Any domain
controller

-
The locations to
install AD DS databases will be
displayed. Browse to a different
locations if you need to change the
default paths.

-
Review selection and
click Next

-
Prerequisites checks
will be performed, and the result will
be displayed.
Click Install

-
Installation will be
completed and the server will reboot
automatically.

-
The Server is
successfully configured as an additional
domain controller and AD DS is ready to
be used on this server.
