You can manage all aspects of Group Policy by using the Group Policy Management Console (GPMC). Figure 1 shows the GPMC, and this white paper will refer to this figure many times as you learn about important Group Policy concepts.
Figure 1. Group Policy Management Console
You start the GPMC from the Start menu: Click Start, All Programs, Administrative Tools, Group Policy Management. You can also click Start, type Group Policy Management, and then click Group Policy Management in the Programs section of the Start menu. Windows Server 2008 and Windows Server 2008 R2 include the GPMC when they are running the AD DS role. Otherwise, you can install the GPMC on Windows Server 2008, Windows Server 2008 R2, or Windows 7 as described in the section “Installing the GPMC in Windows 7,” later in this white paper.
Group Policy objects
GPOs contain policy settings. You can think of GPOs as policy documents that apply their settings to the computers and users within their control. If GPOs are policy documents, then the GPMC is like Windows Explorer. You use the GPMC to create, move, and delete GPOs just as you use Windows Explorer to create, move, and delete files.
In the GPMC, you see all the domain’s GPOs in the Group Policy objects folder. In Figure 1, the callout number 1 shows three GPOs for the domain corp.contoso.com domain. These GPOs are:
- Accounting Security. This is a custom GPO created specifically for Contoso, Ltd.
- Default Domain Controller Policy. Installing the AD DS server role creates this policy by default. It contains policy settings that apply specifically to domain controllers.
- Default Domain Policy. Installing the AD DS server role creates this policy by default. It contains policy settings that apply to all computers and users in the domain.
Group Policy Links
At the top level of AD DS are sites and domains. Simple implementations will have a single site and a single domain. Within a domain, you can create organizational units (OUs). OUs are like folders in Windows Explorer. Instead of containing files and subfolders, however, they can contain computers, users, and other objects.
For example, in Figure 1 you see an OU named Departments. Below the Departments OU, you see four subfolders: Accounting, Engineering, Management, and Marketing. These are child OUs. Other than the Domain Controllers OU that you see in Figure 1, nothing else in the figure is an OU.
What does this have to do with Group Policy links? Well, GPOs in the Group Policy objects folder have no impact unless you link them to a site, domain, or OU. When you link a GPO to a container, Group Policy applies the GPO’s settings to the computers and users in that container. In Figure 1, the callout number 1 points to two GPOs linked to OUs:
- The first GPO is named Default Domain Policy, and this GPO is linked to the domain corp.contoso.com. This GPO applies to every computer and user in the domain.
- The second GPO is named Accounting Security, and this GPO is linked to the OU named Accounting. This GPO applies to every computer and user in the Accounting OU.
In the GPMC, you can create GPOs in the Group Policy objects folder and then link them—two steps. You can also create and link a GPO in one step. Most of the time, you will simply create and link a GPO in a single step, which the section “Creating a GPO,” later in this white paper, describes.
Group Policy Inheritance
As the previous section hinted, when you link a GPO to the domain, the GPO applies to the computers and users in every OU and child OU in the domain. Likewise, when you link a GPO to an OU, the GPO applies to the computers and users in every child OU. This concept is called inheritance.
For example, if you create a GPO named Windows Firewall Settings and link it to the corp.contoso.com domain in Figure 1, the settings in that GPO apply to all of the OUs you see in the figure: Departments, Accounting, Engineering, Management, Marketing, and Domain Controllers. If instead you link the GPO to the Departments OU, the settings in the GPO apply only to the Departments, Accounting, Engineering, Management, and Marketing OUs. It does not apply to the entire domain or the Domain Controllers OU. Moving down one level, if you link the same GPO to the Accounting OU in Figure 1, the settings in the GPO apply only to the Accounting OU, as it has no child OUs. In the GPMC, you can see what GPOs a container is inheriting by clicking the Group Policy Inheritance tab (callout number 1 in Figure 2).
Figure 2. Group Policy inheritance and precedence
So, what happens if multiple GPOs contain the same setting? This is where order of precedence comes into play. In general, the order in which Group Policy applies GPOs determines precedence. The order is site, domain, OU, and child OUs. As a result, GPOs in child OUs have a higher precedence than GPOs linked to parent OUs, which have a higher precedence than GPOs linked to the domain, which have a higher precedence than GPOs linked to the site. An easy way to think of this is that Group Policy applies GPOs from the top down, overwriting settings along the way. In more advanced scenarios, however, you can override the order of precedence.
You can also have—within a single OU—multiple GPOs that contain the same setting. Like before, the order in which Group Policy applies GPOs determines the order of precedence. In Figure 2, you see two GPOs linked to the domain corp.contoso.com: Windows Firewall Settings and Default Domain Policy. Group Policy applies GPOs with a lower link order after applying GPOs with a higher link order. In this case, it will apply Windows Firewall Settings after Default Domain Policy. Just remember that a link order of 1 is first priority, and a link order of 2 is second priority. You can change the link order for a container by clicking the up and down arrows as shown by callout number 2 in Figure 2.
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| As you are probably realizing by now, Group Policy is a remarkably versatile tool. However, Group Policy provides the opportunity to make things overly complicated. In simple environments, such as labs and small businesses, there is nothing wrong with linking all of your GPOs to the domain. Keep it simple. There should be a justification for complication. In Figure 1, if you wanted to create a GPO and link it only to the Engineering and Marketing OUs, the justification should be that the GPO contains settings that apply only to those two departments and should not be applied to any other department. If you cannot make this justification, then keep things simple by linking the GPO one time to the domain. |
Group Policy Settings
To this point, you have learned about GPOs. You have learned that GPMC is to GPOs and OUs as Windows Explorer is to files and folders. GPOs are the policy documents. At some point, you are going to have to edit one of those documents, though, and the editor you use is the Group Policy Management Editor (GPME), which Figure 3 shows. You open a GPO in the GPME by right-clicking it in the GPMC and clicking Edit. Once you are finished, you simply close the window. The GPME saves your changes automatically, so you do not have to save.
Figure 3. Group Policy Management Editor
In Figure 3, callout numbers 1 and 2 point to Computer Configuration and User Configuration, respectively. The Computer Configuration folder contains settings that apply to computers, regardless of which users log on to them. These tend to be system and security settings that configure and control the computer. The User Configuration folder contains settings that apply to users, regardless of which computer they use. These tend to affect the user experience.
Within the Computer Configuration and User Configuration folders, you see two subfolders (callout numbers 3 and 4 in Figure 3):
- Policies. Policies contains policy settings that Group Policy enforces.
- Preferences. Preferences contains preference settings that you can use to change almost any registry setting, file, folder, or other item. By using preference settings, you can configure applications and Windows features that are not Group Policy–aware. For example, you can create a preference setting that configures a registry value for a third-party application, deletes the Sample Pictures folder from user profiles, or configures an .ini file. You can also choose whether Group Policy enforces each preference setting or not. However, standard user accounts can change most preference settings that you define in the User Configuration folder between Group Policy refreshes.
When you are first learning Group Policy, most of the settings that you will configure will be in the Administrative Templates folders. These are registry-based policy settings that Group Policy enforces. They are different from other policy settings for two reasons. First, Group Policy stores these settings in specific registry locations, called the Policies branches, which standard user accounts cannot change. Group Policy–aware Windows features and applications look for these settings in the registry. If they find these policy settings, they use the policy settings instead of the regular settings. They often disable the user interface for those settings as well.
Second, administrative template files, which have the .admx extension, define templates for these settings. These templates not only define where policy settings go in the registry but also describe how to prompt for them in the GPME. In the Group Policy setting that Figure 4 shows, for example, an administrative template file defines help text, available options, supported operating systems, and so on.
Figure 4. Group Policy setting
When you edit a policy setting, you are usually confronted with the choices that callout numbers 1 to 3 indicate in Figure 4. In general, clicking:
- Enabled writes the policy setting to the registry with a value that enables it.
- Disabled writes the policy setting to the registry with a value that disables it.
- Not Configured leaves the policy setting undefined. Group Policy does not write the policy setting to the registry, and so it has no impact on computers or users.
Generalizing what enabled and disabled means for every policy setting is not possible. You can usually read the help text, shown in callout number 5, to determine exactly what these choices mean. You must also be careful to read the name of the policy setting. For example, some policy settings say, “Turn on feature X,” whereas other policy settings say, “Turn off feature Y.” Enabled and disabled have different meanings in each case. Until you are comfortable, make sure you read the help text for policy settings you configure.
Some policy settings have additional options that you can configure. Callout number 4 in Figure 4 shows the options that are available for the Group Policy refresh interval policy setting. In most cases, the default values match the default values for Windows. As well, the help text usually gives detailed information about the options you can configure.
Group Policy Refresh
As you learned in the previous section, GPOs contain both computer and user settings. Group Policy applies:
- Computer settings when Windows starts.
- User settings after the user logs on to the computer.
Group Policy also refreshes GPOs on a regular basis, ensuring that Group Policy applies new and changed GPOs without waiting for the computer to restart or the user to log off. The period of time between these refreshes is called the Group Policy refresh interval, and the default is 90 minutes with a bit of randomness built in to prevent all computers from refreshing at the same time. If you change a GPO in the middle of the day, Group Policy will apply your changes within about 90 minutes. You don’t have to wait until the end of the day, when users have logged off of or restarted their computers. In advanced scenarios, you can change the default refresh interval.
Creating a GPO
You create a GPO by using the GPMC. There are two ways to create a GPO:
- Create and link a GPO in one step.
- Create a GPO in the Group Policy objects folder, and then link it to the domain or OU.
The instructions in this section describe how to create and link a GPO in one step.
You can start with a blank GPO, which the instructions describe, or you can use a starter GPO.
To create and link a GPO in the domain or an OU
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In the GPMC, right-click the domain or OU in which you want to create and link a GPO, and click Create a GPO in this domain, and Link it here.
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In the Name box on the New GPO dialog box, type a descriptive name for the GPO, and then click OK.
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Editing a GPO
In the GPMC, you can open GPOs in the GPME to edit them within any container. To see all of your GPOs, regardless of where you link them, use the Group Policy objects folder to edit them.
To edit a GPO in the domain, an OU, or the Group Policy objects folder
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In the left pane of the GPMC, click Group Policy objects to display all the domain’s GPOs in the right pane. Alternatively, you can click the domain or any OU to display that container’s GPOs in the right pane.
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In the right pane of the GPMC, right-click the GPO that you want to edit, and click Edit to open the GPO in the GPME.
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In the GPME, edit the Group Policy settings that you want to change, and close the GPME window when finished. You do not have to save your changes, because the GPME saves your changes automatically.
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Linking a GPO
If you create and link GPOs in one step, you do not have to manually link GPOs to the domain or OUs. However, if you create a GPO in the Group Policy objects folder or unlink a GPO and want to restore it, you will need to manually link the GPO. The easy way to link a GPO is to simply drag the GPO from the Group Policy objects folder and drop it onto the domain or OU to which you want to link it.
To link a GPO to a domain or OU
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In the GPMC, right-click the domain or OU to which you want to link the GPO, and then click Link an Existing GPO.
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In the Select GPO dialog box, click the GPO that you want to link to the domain or OU, and then click OK.
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Unlinking a GPO
You unlink a GPO when you no longer want to apply it to the domain or OU (or its child OUs). You can later restore the link, as the section titled “Linking a GPO” described.
Unlinking a GPO from a domain or OU does not delete the GPO. It only deletes the link. After unlinking a GPO, you can still find it in the Group Policy objects folder in the GPMC.
To unlink a GPO from a domain or OU
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In the GPMC, click the domain or OU containing the GPO that you want to unlink.
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Right-click the GPO that you want to unlink from the domain or OU, and click Delete.
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In the Group Policy Management dialog box, click OK.
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Deleting a GPO
Deleting a GPO is not the same as unlinking a GPO from a domain or OU. You delete GPOs within the Group Policy objects folder. Doing so removes not only the links but also the GPO itself.
To delete a GPO from the Group Policy objects folder
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In the GPMC, click the Group Policy objects folder.
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In the right pane of the GPMC, right-click the GPO that you want to delete, and click Delete.
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In the Group Policy Management dialog box, click Yes to confirm that you want to delete the GPO and its links.
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In the Delete dialog box, confirm that the deletion was successful, and click OK.
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