Mastering Remote Desktop Services: Leverage Group Policy for Enhanced Windows Server Control

Table of Contents

This article provides a comprehensive guide on effectively applying Group Policy Objects (GPOs) to Remote Desktop Services (RDS) servers within an Active Directory domain environment. Leveraging GPOs is a crucial step for domain administrators to control the user environment and server configuration specifically for RDS deployments.

Summary¶

When Remote Desktop Services servers are members of an Active Directory domain, domain administrators utilize Group Policy Objects (GPOs) as a primary tool to manage and control various aspects of both the server configuration and the user experience within RDS sessions. This document outlines a recommended methodology for implementing GPOs targeted specifically at RDS environments. The goal is to achieve fine-grained control over these servers and the user sessions they host without negatively impacting other servers or user workstations across the network. Applying GPOs effectively to RDS servers requires careful planning, considering whether the policies apply to the computer objects representing the servers or the user accounts logging into them.

Why Dedicated GPOs for RDS?¶

Remote Desktop Services servers often serve a distinct purpose within an IT infrastructure. Users interact with these servers remotely to run applications or access desktops. Consequently, the configuration and user experience requirements for RDS servers are typically different from standard member servers or user workstations. Applying generic domain-wide policies to RDS servers can lead to undesired configurations, performance issues, or security vulnerabilities specific to the multi-user nature of the environment.

Creating dedicated GPOs specifically for RDS allows administrators to:
* Enhance Security: Implement stricter security settings, restrict software execution, or configure firewall rules tailored to the RDS role.
* Optimize Performance: Apply policies that manage resource usage, session limits, or disable unnecessary features to improve the performance for multiple concurrent users.
* Control User Environment: Customize the user desktop, restrict access to specific settings, enforce folder redirection, or manage drive mappings, providing a consistent and controlled user experience.
* Simplify Management: Isolate RDS configuration settings, making them easier to manage, test, and troubleshoot without affecting other parts of the network.

Computer Policy Settings: The Power of OUs¶

A highly recommended approach for applying computer configuration settings specifically to your Remote Desktop Services servers is to place their computer objects into their own dedicated Organizational Unit (OU) within Active Directory. This structural separation allows you to create GPOs containing computer configuration settings that are linked only to this specific OU. This ensures that these particular policies are applied exclusively to the RDS servers within that OU.

By isolating the RDS servers in their own OU, you gain precise control over the computer-level policies that affect them. This prevents RDS-specific computer settings from being applied to other server roles or user workstations. The dedicated OU serves as a clear administrative boundary, making it easier to delegate management authority if needed. To maximize effectiveness, this OU should ideally contain only the computer accounts for your RDS servers and no other object types like user accounts or other server roles.

Consider the hierarchy of your existing Active Directory structure when deciding where to place the new OU.
* Child OU: Placing the new OU as a child of the existing OU where your RDS servers currently reside is a common practice. This way, the new RDS-specific OU inherits the relevant policies from its parent OU, and you can then apply additional, more specific GPOs directly to the child OU. This works well if most or all of your RDS server computer accounts are already grouped under a single parent OU.
* Sibling OU: Alternatively, creating the new OU as a sibling to the current OU holding the RDS server objects might fit better depending on your administrative model. In this scenario, you would need to ensure that any necessary policies from the existing OUs are also linked to the new RDS OU to maintain baseline configurations.

For a visual representation of the OU structure concept:

mermaid graph TD A[Your Domain] --> B[Existing Servers OU]; A --> C[Existing Workstations OU]; B --> D[RDS Servers OU]; D --> E[RDS Server 01 Computer Object]; D --> F[RDS Server 02 Computer Object]; style D fill:#f9f,stroke:#333,stroke-width:2px
Conceptual diagram illustrating a dedicated OU for RDS Servers within the domain hierarchy.

To create a new Organizational Unit for your Remote Desktop Services servers, follow these steps:

1. Log in to a domain controller or a machine that has the Remote Server Administration Tools (RSAT) installed and configured to manage Active Directory.
2. Open the Start menu, type “Active Directory Users and Computers,” and select the application from the search results.
3. In the Active Directory Users and Computers console tree, navigate to the domain or specific container where you intend to create the new OU.
4. Right-click the chosen domain or container, point to New, and then select Organizational Unit.
5. In the New Object - Organizational Unit dialog box, enter a descriptive name for the new OU, such as “Remote Desktop Services Servers” or “RDS Farm Servers”.
6. Click OK to finalize the creation of the new OU.

Once the OU is created, you need to move the computer accounts for your RDS servers into this new OU. In the Active Directory Users and Computers console, locate the computer accounts, right-click each one, select Move…, and then choose the new RDS OU as the destination.

Next, you need to create a Group Policy Object specifically for these RDS servers and link it to the new OU.

To create and link a Remote Desktop Services computer Group Policy Object, follow these steps:

1. Open the Start menu, type “Group Policy Management,” and select the application from the search results.
2. In the Group Policy Management console tree, navigate to your domain.
3. Expand the domain and locate the Group Policy Objects container. Right-click this container and select New.
4. Enter a descriptive name for the new GPO in the New GPO dialog, such as “RDS Servers Computer Policy”.
5. Click OK to create the GPO within the Group Policy Objects container.
6. Now, navigate to the Remote Desktop Services Servers OU you created earlier in the console tree.
7. Right-click the Remote Desktop Services Servers OU and select Link an Existing GPO….
8. In the Select GPO dialog box, choose the “RDS Servers Computer Policy” (or whatever you named it) from the list of available GPOs.
9. Click OK to establish the link between the GPO and the OU. The computer policies defined within this GPO will now apply to the computer objects located in the “Remote Desktop Services Servers” OU during the next policy refresh cycle.
10. Right-click the newly linked GPO under the RDS OU and select Edit to open the Group Policy Management Editor. Here, you can navigate to Computer Configuration -> Policies and configure the desired settings relevant to your RDS server computers. Common configurations include security options, system services, software installation/restriction policies, and specific Remote Desktop Session Host settings.

By configuring settings under Computer Configuration, you are applying policies that affect the operating system and services running on the RDS servers themselves, regardless of which user is logged on.

User Policy Settings: Implementing Loopback Processing¶

Applying User Configuration GPO settings to users only when they log on to Remote Desktop Services servers presents a unique challenge. Normally, user policies are applied based on the location of the user account in Active Directory. However, you might want specific user settings (like desktop appearance, drive mappings, or application restrictions) to apply only when a user logs into an RDS server, and not when they log into their standard workstation. This is where Group Policy Loopback Processing comes into play.

Group Policy Loopback Processing is a computer-side setting that changes how user policies are processed for users logging onto computers where loopback is enabled. When enabled on your RDS servers, the system deviates from the default GPO processing order. Instead of processing user policies based solely on the user object’s location, it considers the computer object’s location as well.

There are two modes for loopback processing: Replace and Merge. The original text specifically mentions Merge mode, which is a common and often flexible approach for RDS environments.

• Merge Mode: In this mode, user policies are processed in two stages. First, the system processes the GPOs linked to or inherited by the user’s account location in Active Directory, applying those user settings. Second, it processes the user policies from the GPOs linked to or inherited by the computer’s location (your RDS Servers OU). The user settings from the computer-applied GPOs are applied after the standard user GPOs. If there are conflicting settings, the settings from the computer-applied GPOs (linked to the RDS OU) take precedence, effectively overriding the user’s normal GPO settings for that specific session.
• Replace Mode: In this mode, the system completely ignores the user policies linked to or inherited by the user’s account location. Only the user policies from the GPOs linked to or inherited by the computer’s location (the RDS Servers OU) are processed and applied. This provides a very strict, uniform user experience on the RDS servers, completely replacing their normal user policy settings.

Merge mode is frequently preferred as it allows users to retain some of their standard user settings (like basic security options or core drive mappings) while layering on RDS-specific configurations (like desktop lockdowns or software restrictions specific to the RDS environment).

To implement loopback processing in Merge mode for your RDS servers, you need to configure a specific computer policy setting within the GPO linked to your RDS Servers OU. The setting is located at:
Computer Configuration -> Policies -> Administrative Templates -> System -> Group Policy -> Configure user Group Policy loopback processing mode. Enable this setting and select “Merge” from the dropdown menu.

Next, you need to create a separate GPO containing the desired User Configuration settings that you want to apply specifically when users log on to the RDS servers. This GPO should also be linked to the RDS Servers OU. Even though it contains User Configuration settings, it is linked to the Computer OU because Loopback Processing (a Computer setting) causes the system to look for user policies linked to the computer’s location.

To create and link a Group Policy Object for RDS user settings (to be used with loopback), follow these steps:

1. Open the Group Policy Management console.
2. Navigate to the Group Policy Objects container under your domain. Right-click the container and select New.
3. Enter a name for this new GPO, such as “RDS Users Policy Loopback”. Click OK.
4. Navigate to the Remote Desktop Services Servers OU in the console tree. Right-click the OU and select Link an Existing GPO….
5. In the Select GPO dialog, choose “RDS Users Policy Loopback” from the list. Click OK.
6. Right-click the newly linked GPO under the RDS OU and select Edit.
7. Navigate to User Configuration -> Policies and configure the settings you want applied to users only when they log onto the RDS servers. This might include desktop restrictions, Start menu layouts, folder redirection, drive mappings, software restriction policies, or specific Remote Desktop Session Host user settings.

Security Filtering for Loopback GPOs:

For the Loopback processing to function correctly, the computer accounts of the RDS servers in the OU must have Read and Apply Group Policy permissions on the GPO containing the User Configuration settings intended for loopback processing (e.g., “RDS Users Policy Loopback”). By default, the “Authenticated Users” group has these permissions, and this group typically includes computer accounts. However, it is a best practice for GPOs using loopback to explicitly add the relevant computer group (or individual computer accounts) to the GPO’s security filtering.

To ensure the RDS server computer accounts can process the loopback GPO, follow these steps:

1. In the Group Policy Management console, select the GPO that contains the User Configuration settings intended for loopback processing (e.g., “RDS Users Policy Loopback”).
2. In the scope pane (usually the right-hand pane), select the Scope tab.
3. Scroll down to the Security Filtering section. The “Authenticated Users” group is usually listed here by default.
4. Click Add. In the Select User, Computer, or Group box, enter the names of the RDS server computer accounts or, preferably, a security group containing these computer accounts. Click Check Names and then OK.
5. Select the computer account(s) or group you just added in the Security Filtering box.
6. Now, look at the Permissions section below the Security Filtering (or sometimes accessed by right-clicking the GPO and selecting Properties, then the Security tab). Ensure that the selected computer account(s) or group have Read and Apply Group Policy permissions set to Allow.
7. Click OK to save the changes to the GPO’s security filtering.

This ensures that only the specified computers (your RDS servers) will attempt to process this GPO, which is essential for Loopback processing to work as intended and prevent the user policies from being applied to computers where loopback is not enabled or desired.

For a more in-depth understanding of Group Policy Loopback Processing, you might find this video helpful:

(Note: Please replace ‘video-id-here’ with the actual YouTube video ID for a relevant video on Group Policy Loopback Processing when embedding)

Important Security Considerations¶

A critical security principle is to avoid installing the Remote Desktop Session Host role on Domain Controllers (DCs). While technically possible in some older Windows Server versions, it is strongly discouraged and can create significant security risks.

Reasons why you should not use Domain Controllers as RDS servers:

• Elevated Access: Users logging onto a DC as an RDS server gain interactive logon rights on a machine that holds sensitive directory data. While user rights assignments can be restricted via GPO, the fundamental risk of general users interactively logging onto a DC is high. Only administrators with a legitimate need should log onto a DC.
• Increased Attack Surface: Running the RDS role on a DC exposes additional services and ports to potential attackers. Any vulnerability in the RDS components could potentially compromise the entire domain.
• Privilege Escalation Risk: If an attacker manages to gain a foothold on a DC used as an RDS server, even with limited user privileges, they are one step closer to potentially exploiting a vulnerability that grants higher privileges, potentially leading to a full compromise of the Active Directory environment. Many attacks target local system vulnerabilities; gaining LocalSystem on a DC provides control over the entire forest.
• Policy Conflicts: DCs have default security policies applied specifically to them. Applying RDS configurations on top of these can lead to complex policy conflicts and unpredictable behavior.

It is paramount to maintain DCs as dedicated infrastructure servers with minimal roles and limited interactive access to highly trusted administrators only. Deploy RDS on separate member servers within the domain.

Applying and Troubleshooting Group Policies¶

After creating and linking GPOs to your RDS Servers OU and configuring the necessary computer and user settings (including Loopback processing), the policies will apply during the next regular Group Policy refresh cycle (which happens automatically in the background) or when the computer restarts.

To force an immediate policy refresh on an RDS server for testing or deployment purposes, you can use the gpupdate command. Open a command prompt or PowerShell as an administrator on the RDS server and run:

gpupdate /force

This command refreshes both computer and user policies immediately.

To verify which policies are being applied to a specific RDS server and a user session on that server, you can use the Resultant Set of Policy (RSoP) tool or the gpresult command.
* RSoP: Run rsop.msc on the RDS server. This graphical tool shows the combined effect of all applied GPOs for the computer and the currently logged-on user. It helps identify which settings are being applied and from which GPO they originate, aiding in troubleshooting conflicts.
* gpresult: This command-line tool provides similar information. Running gpresult /r in a user session on the RDS server shows the applied user and computer policies. Using /scope computer or /scope user allows focusing on specific policy types. gpresult /h C:\temp\rsop.html can generate an HTML report for easier review.

Understanding GPO inheritance and processing order is key to troubleshooting. Policies applied at higher levels (like the domain) are inherited by OUs below them. Policies linked directly to an OU take precedence over inherited policies from parent OUs, assuming no enforcement (No Override) is configured on the parent policy links. The processing order is Local Policy -> Site Policies -> Domain Policies -> OU Policies (from highest to lowest level in the AD hierarchy). Loopback processing changes the user policy order as described earlier.

Implementing GPOs for RDS requires careful planning and testing, but it provides the granular control necessary to secure and optimize your Remote Desktop Services environment effectively.

Have you implemented dedicated GPOs for your RDS servers? What specific policies have you found most beneficial for securing or optimizing your environment? Share your experiences and insights in the comments below!