RODC Staged Installation

RODC in Remote Branch Office

RODC is a new feature added in Windows Server 2008. For remote branch office,poor network connectivity, less secure location, low user base we can use RODC. RODC can be run on Windows Server 2008 Core Installation with least requirements like memory,HDD, processor. A low end server would be enough for this kind of setup hence proving to be cost effective.

We would be doing a Staged Installation of RODC. In this type of installation There are two stages.

Before we begin lets take a look at prerequistives.

1. Forest Functional Level and Domain functional level must be windows server 2003 or higher.
2. At least one writeable windows server 2008 Domain Controller.
3. Adprep /rodcprep must be run. Running this will give update permission on all DNS servers and allow them to be replicated by RODC which are running DNS as well.

Verifying rodcprep success

To verify that adprep /rodcprep completed successfully
   1. Log on to an administrative workstation that has ADSIEdit installed. ADSIEdit is installed by default on domain controllers that run Windows Server 2008 or Windows Server 2008 R2.
   2. Click Start, click Run, type ADSIEdit.msc, and then click OK.
   3. Click Action, and then click Connect to.
   4. Click Select a well known Naming Context, select Configuration in the list of available naming contexts, and 
       then click OK.
   5. Double-click Configuration, and then double-click CN=Configuration,DC=forest_root_domain
      where forest_root_domain is the distinguished name of your forest root domain.
   6. Double-click CN=ForestUpdates.
   7. Right-click CN=ActivedirectoryRodcUpdate, and then click Properties.
   8. Confirm that the Revision attribute value is 2, and then click OK.

To install RODC there are 3 options available.

1. Running directly using dcpromo /adv setup
2. Install from Media
3. Staged Installation

As mentioned earlier we would be doing RODC using staged installation

First: member of domain admin adds necessary computer accout information, site info, dns, gc.

Steps for creating Pre Staged RODC installation account

To create an RODC account by using the Windows interface

1. Click Start, click Administrative Tools, and then click Active Directory Users and Computers.
2. Double-click the domain container, then you can either right-click the Domain Controllers container or click the Domain Controllers container, and then click Action.
3. Click Pre-create Read-only Domain Controller account, as shown in the following figure.

4. On the Welcome to the Active Directory Domain Services Installation Wizard page, if you want to modify the default the Password Replication Policy, select Use advanced mode installation, and then click Next.
5. On the Network Credentials page, under Specify the account credentials to use to perform the installation, click My current logged on credentials, as shown in the following figure, or click Alternate credentials, and then click Set. In the Windows Security dialog box, provide the user name and password for an account that can install the additional domain controller. To install an additional domain controller, you must be a member of the Enterprise Admins group or the Domain Admins group. When you are finished providing credentials, click Next.

6. On the Specify the Computer Name page, type the computer name of the server that will be the RODC.
7. On the Select a Site page, select a site from the list or select the option to install the domain controller in the site that corresponds to the IP address of the computer on which you are running the wizard, and then click Next.
8. On the Additional Domain Controller Options page, make the following selections, as shown in the following figure, and then click Next:
• DNS server: This option is selected by default so that your domain controller can function as a DNS server. If you do not want the domain controller to be a DNS server, clear this check box. However, if you do not install the DNS server role on the RODC and the RODC is the only domain controller in the branch office, users in the branch office will not be able to perform name resolution when the WAN to the hub site is offline.
• Global catalog: This option is selected by default. It adds the read-only directory partitions of the global catalog to the domain controller, and it enables global catalog search functionality. If you do not want the domain controller to be a global catalog server, clear this option. However, if you do not install a global catalog server in the branch office or enable universal group membership caching for the site that includes the RODC, users in the branch office will not be able to log on to the domain when the WAN to the hub site is offline.
• Read-only domain controller. When you create an RODC account, this option is selected by default and you cannot clear it.
9. If you selected the Use advanced mode installation check box on the Welcome page, the Specify the Password Replication Policy page appears. By default, no account passwords are replicated to the RODC, and security-sensitive accounts (such as members of the Domain Admins group) are explicitly denied from ever having their passwords replicated to the RODC.

To accept the default setting, click Next.

-or-

To add other accounts to policy, click Add. If you want the accounts to be allowed to have their passwords replicated to the RODC, click Allow passwords for the account to replicate to this RODC. If you want the accounts to be denied from having their passwords replicated to the RODC, click Deny passwords for the account from replicating to this RODC. Then, click OK. When you are done adding other accounts, click Next.

When you install the first RODC in a domain, domain group accounts that are required for RODCs to function are created. Depending on your replication topology, the wizard might return an error indicating that these group accounts are not available when you try to install another RODC in the domain. In this case, wait for replication to complete before you install the additional RODC.

10. In Select Users, Computers, and Groups, type the names of the accounts that you want to add to the policy, and then click OK.
11. On the Delegation of RODC Installation and Administration page, type the name of the user or the group who will attach the server to the RODC account that you are creating, as shown in the following figure. You can type the name of only one security principal.

To search the directory for a specific user or group, click Set. In Select Users, Computers, or Groups, type the name of the user or group. We recommend that you delegate RODC installation and administration to a group.

This user or group will also have local administrative rights on the RODC after the installation. If you do not specify a user or group, only members of the Domain Admins group or the Enterprise Admins group will be able to attach the server to the account.

When you are finished, click Next.

12. On the Summary page, review your selections. Click Back to change any selections, if necessary.

To save the settings that you selected to an answer file that you can use to automate subsequent AD DS operations, click Export settings. Type a name for your answer file, and then click Save.

When you are sure that your selections are accurate, click Next to create the RODC account.

13. On the Completing the Active Directory Domain Services Installation Wizard page, click Finish.

After you create the account for the RODC, the user or group to whom you delegated installation and administration of the RODC (in step 11 in the previous procedure) can run the Active Directory Domain Services Installation Wizard on the server that will become the RODC to complete the RODC installation. Make sure that the server is not joined to the domain before you start the wizard.

To attach a server to an RODC account using the Windows interface

1. Log on as local Administrator to the server that will become the RODC, and then open a command prompt.
2. Type the following command, and then press ENTER:

dcpromo /UseExistingAccount:Attach

3. On the Welcome to the Active Directory Domain Services Installation Wizard page, click Next, or, if you want to install from media or identify the source domain controller for AD DS replication, select the Use advanced mode installation check box.
4. On the Network Credentials page, type the name of any existing domain in the forest where you plan to install the additional domain controller, as shown in the following figure. Under Specify the account credentials to use to perform the installation, click Alternate credentials, and then click Set. In the Windows Security dialog box, provide the user name and password for an account that was delegated the ability to install and administer the RODC when the RODC account was created. When you are finished providing credentials, click Next.

5. On the Select Domain Controller Account page, confirm that the wizard has found an existing RODC account that matches the name of the server, and then click Next.
6. On the Location for Database, Log Files, and SYSVOL page, type or browse to the volume and folder locations for the database file, the directory service log files, and the system volume (SYSVOL) files, and then click Next.

Windows Server Backup backs up the directory service by volume. For backup and recovery efficiency, store these files on separate volumes that do not contain applications or other nondirectory files.

7. On the Directory Services Restore Mode Administrator Password page, type and confirm the restore mode password, and then click Next. This password is used to start AD DS in Directory Service Restore Mode for tasks that must be performed offline. The password complexity and length must comply with the domain security policy.
8. On the Summary page, review your selections. Click Back to change any selections, if necessary.

To save the settings that you selected to an answer file that you can use to automate subsequent AD DS operations, click Export settings. Type a name for your answer file, and then click Save.

Part B

I have installed RODC on Windows core installation.

You will need to create an answer file in order for RODC setup to be successfully completed.

You need to use command line or you can use CoreConfigurator to finish RODC.

dcpromo /unattend /UseExistingAccount:Attach /ReplicaDomainDNSName: contoso.com /UserDomain:contoso.com /UserName:contoso\da1 /password:* /databasePath:"e:\Windows\ntds" /logPath:"e:\Windows\ntds" /sysvolpath:"e:\Windows\sysvol" /safeModeAdminPassword:FH#3573.cK /rebootOnCompletion:yes

The contents of answer file are as follows

I have used CoreConfiguration to generate answerfile. It can them be modified as per needs.

I hope this post would be informational for you.