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Dude, where’s my GPO? Using PowerShell to find all of your Group Policy links.

  • Artigo

Stratego Stratego

I only played Stratego once as a kid when I was over at a friend’s house. Strategy, challenge and mystery made the game captivating. A few years ago I bought a vintage 1961 edition on eBay so I could teach my sons to play. As it turns out this game has been around for centuries among various cultures around the world. Pieces are ranked from 1 to 9, with 1 being the most powerful (unless you have a newer edition where the numbers have been revised). The objective is to capture the opponent’s flag while avoiding the bombs hidden among the ranks. By now you are probably wondering what this has to do with PowerShell or Active Directory.  Keep reading and find out.

GPO Scavenger Hunt

Using the Get-GPOReport cmdlet from the Group Policy PowerShell module you can easily create a report of all your Group Policy Objects (GPOs) like this:

 

 PS C:\> Import-Module GroupPolicy
PS C:\> Get-GPOReport -All -ReportType HTML -Path .\GPO.html

 

This is a great report, but it can be a bit overwhelming.  What if you want a simple spreadsheet listing of the same information?

Back around 2002 I wrote some code for this in VBScript.  You see, back then Group Policy Management Console (GPMC) had not been released yet.  At that time you created GPOs through AD Users and Computers (ADUC).  I was working with Windows 2000 Server designing OUs and GPOs for a large company’s Windows 2000 implementation.  I needed a report to show me where all of these policies were linked, and I also needed to know where inheritance was blocked and where policies were set to “No Override” (now called “Enforced”).  After some recent conversations with peers I decided to rewrite this script in PowerShell.

Understanding GPOs in Active Directory

First off, technically speaking Group Policy is not a feature of Active Directory (AD).  However, so much of the infrastructure rides on AD that most people associate the two.  If you need some help understanding GPOs start here:  Everything you need to get started with Group Policy.

In GPO terms, domains, OUs, and sites are called Scopes of Management (SOMs).  They have an attribute called gPLink that lists all of the GPOs applied to the object.  The gPLink attribute contains a list of GPO distinguished names and a gPLinkOptions value for each one.  This numeric value is a bit switch flagging LinkEnabled status and Enforced status.  SOMs have an attribute call gPOptions which specifies whether Block Inheritance is enabled.  To understand these in more detail you can explore the following links:

Remember that Stratego reference?

imageThe gPLink attribute is a string concatenation that looks something like this:

[LDAP://cn={7BE35F55-E3DF-4D1C-8C3A-38F81F451D86},cn=policies, cn=system,DC=wingtiptoys,DC=local;2][LDAP://cn={046584E4-F1CD-457E-8366-F48B7492FBA2}, cn=policies,cn=system,DC=wingtiptoys,DC=local;0] [LDAP://cn={12845926-AE1B-49C4-A33A-756FF72DCC6B},cn=policies, cn=system,DC=wingtiptoys,DC=local;1]

As you can see, each GPO distinguished name is enclosed with square brackets, and there is a numeric digit following it as described above.  The important point is that GPOs are listed in this string in order of precedence.  In the GPMC GUI you will see multiple linked policies listed top to bottom, 1 through x, with lower numbers winning over higher numbers.  This is just like Stratego.  The #1 policy (Stratego’s marshall) wins over all the others.  Lower numbers always win.

Where’s the PowerShell?

Understanding how policies tie into Active Directory, now you can see that we need a couple targeted LDAP queries to get all of the gPLink and gPOptions attributes from the SOMs.  Then we parse out the attributes and put them into a report.  I am over-simplifying it just a bit, but here are the queries:

 

 # Empty array to hold all possible GPO links            
$gPLinks = @()            
            
# GPOs linked to the root of the domain            
# !!! Get-ADDomain does not return the gPLink attribute            
$gPLinks += Get-ADObject -Identity (Get-ADDomain).distinguishedName ` 
-Properties name, distinguishedName, gPLink, gPOptions            
            
# GPOs linked to OUs            
# !!! Get-GPO does not return the gPLink attribute            
$gPLinks += Get-ADOrganizationalUnit -Filter * -Properties name, ` 
distinguishedName, gPLink, gPOptions            
            
# GPOs linked to sites            
$gPLinks += Get-ADObject -LDAPFilter '(objectClass=site)' ` 
-SearchBase "CN=Sites,$((Get-ADRootDSE).configurationNamingContext)" ` 
-SearchScope OneLevel -Properties name, distinguishedName, gPLink, gPOptions

 

Notice in the script comments that Get-ADDomain and Get-GPO do not return the gPLink attribute.  We have to specifically query for this attribute using other cmdlets.  Also notice that I am not filtering out SOMs without a gPLink attribute.  I want to collect all OUs and sites to round out the report, not just the ones with policies linked.

You can download the full script from the TechNet Script Gallery.  The output is a CSV file (gPLink_Report.csv) listing all of the linked policies, their locations, and link configurations.  The report contains the following columns:

  • SOM – Scope of Management, the domain, OU, or site where the policy is linked.  The OUs are tabbed to represent the tree structure for easy viewing.
  • DistinguishedName – Full path to the SOM.
  • BlockInheritance – True if the OU is blocking policy inheritance.  This comes from the gPOptions attribute.
  • LinkEnabled – This is represented by bit 1 of the gPLinkOptions numeric in the gPLink string.
  • Enforced – This is represented by bit 2 of the gPLinkOptions numeric in the gPLink string. This setting is ignored for the policy if not enabled (bit 1).
  • Precedence – Stratego ranking of multiple policies linked to the same SOM.
  • DisplayName – Friendly name of the policy.
  • GPOStatus – All settings enabled. User settings disabled. Computer settings disabled. All settings disabled. Note that this is different than the enabled/disabled status on the gPLink itself.
  • WMIFilter – Name of the WMI filter on the policy, if configured.
  • GUID – The GPO GUID that can be used to identify the policy in ADSIEDIT or the SYSVOL share.
  • PolicyDN – The full path to the group policy container object in Active Directory.

This script has the following prerequisites:

  • PowerShell v2 or above
  • Remote Server Administration Tools (RSAT)
  • AD PowerShell module
  • Group Policy module

Unlike Get-GPOReport this script does NOT include any of the following other related information:

  • Policy filtering by permissions
  • GPOs that are not linked
  • Individual policy settings

With this handy CSV spreadsheet you can easily get an overview of your policies, where they are blocked, and where they are enforced.  Perhaps the helpdesk could use a copy of the script and report when they are troubleshooting group policy calls (in addition to RSOP, of course).

Group Policy Health Check (GPOHC)

As a Microsoft Premier Field Engineer I am part of a global team with many specialties.  Some of my peers are true group policy experts.  You can have one of them visit your company, teach you the ins and outs of group policy, and help optimize your GPOs.  They have many other tricks up their sleeve beyond today’s reporting script.  This service is called the Group Policy Health Check (GPOHC) .  Use the links at the bottom of this blog post or contact me for more information if you would like one of these at your company.

The Download

Download today’s script at the TechNet Script Gallery.

UPDATE:  For a new, improved version of this script go to this post.

Comments

  • Anonymous
    May 30, 2013
    Have you used List Object Mode in AD to be able to hide GPOs so that certain SAs could not see them and link them?  Is there any documentation on doing this?

  • Anonymous
    May 31, 2013
    Hi Brian, We have public documentation on TechNet that describes procedures for List Object Mode in AD, but that is really intended for shared hosting environments rather than tradition customer implementations. Have you experimented with "Deny", "Read all properties", "Descendant groupPolicyContainer Objects" on this container "CN=Policies,CN=System,DC=contoso,DC=com"? Ashley

  • Anonymous
    June 15, 2013
    After applying the group policies , the client machines takes long time to authenticate . Could you please suggest any policy I need to  add/ Review  or is there a minimum policies that I can push to the clients.

  • Anonymous
    July 02, 2013
    Hello RGPrakash, There are many best practices that can help avoid your issue.  Please see the documents here for more help with Group Policy: blogs.technet.com/.../everything-you-need-to-get-started-with-group-policy.aspx Sincerely, GoateePFE Ashley McGlone

  • Anonymous
    July 03, 2013
    winplat.net/.../List-Group-Policy-Object-using-Powershell.aspx

  • Anonymous
    August 13, 2013
    Hey, I would like to get a list of all the GPOs with their respective settings, because I want to know which of our GPOs use scripts. What would be the command to get a list of all the GPOs with the settings? Thanks!

  • Anonymous
    August 14, 2013
    Hi Marc, You can get a report for that using this command: Get-GPOReport -All -ReportType HTML -Path .GPO.html Hope this help, Ashley

  • Anonymous
    October 25, 2013
    What a great tool. And nice touch adding more underscores to denote the depth of the OUs. Thank you.

  • Anonymous
    November 08, 2013
    Hello Ashley, I was wondering if there is a way to narrow this report down to a specific OU and it's sub OU's. The reason being is I do not administer my entire domain just a site which they have grouped in an OU. If it's possible thanks for any help you can provide. Have a great day.

  • Anonymous
    November 08, 2013
    Ok so I altered the portion where it lists out gpo's linked to OU's and put in -SearchBase "My Top OU DN" that seems to have run without any problems. Thank you for this script it will help me immensely as our organization is trying to standardize it's OU structure. Have a great day.

  • Anonymous
    January 24, 2014
    This is a great script. I tried to connect to another domain using a new PS drive, however, the script was not pulling the display name, GPOStatus, or WMIFilter. Any recommendations to do this? I was only getting the DN of the OU and the GUID.

  • Anonymous
    January 29, 2014
    The comment has been removed

  • Anonymous
    April 14, 2014
    Hi,

    Great Script , But can we the Owner and Security filtering details in this script ..

  • Anonymous
    April 14, 2014
    Hello Gopi,
    I chose to leave that out to keep it simple. I would suggest using the GPO cmdlets to get that report:
    Get-GPOReport -All -ReportType HTML -Path .GPO.html
    Ashley
    @GoateePFE

  • Anonymous
    January 26, 2015
    In a previous post I created a report of all organizational units (OUs) and sites with their linked group policy objects (GPOs) . This report gives visibility to all of our group policy usage at-a-glance. Since this is one of my most popular downloads

  • Anonymous
    February 13, 2015
    Hi Everyone,

    I am looking for a script which givens report of all unlinked GPO's or Orphaned GPO which are not linked to any domains, site. I need to delete all those as a part AD clean up activity

  • Anonymous
    April 23, 2015
    Ashley - Thank you. One issue I have - in my environment, running the script (or "Get-GPO -ALL") only returns details for GPOs with User security filtering. If the GPO is strictly tied to Computer objects (e.g. Domain Computers), the script result is blank for DisplayName, GPOStatus,WMIFilter,and GUID data. I am executing as a Domain Admin, using both PSVersion 3.0 w/Win2008 R2 SP1 & PSVersion 4.0 w/loadWin7 Pro. Ever seen this or have any insight on this shortcoming?

  • Anonymous
    April 23, 2015
    Sorry - moving this to the more recent script section you've referenced

  • Anonymous
    June 16, 2016
    Hi Ashley,You're probably going to get a LOT of comments today because of this article:http://www.infoworld.com/article/3084930/microsoft-windows/microsoft-acknowledges-permission-problems-with-ms16-072-patches-kb-3159398-3163017-3163018-3163016.htmlBest,Roland Thomas

  • Anonymous
    March 20, 2017
    How to get all GPO's linked to an AD-Computer ? I've tried different ways! but looks like I'm missing something! I can get all gpo's linked to an ou, but not sure how to target CN

    • Anonymous
      March 24, 2017
      Hello Abdel,Try using the cmdlets Get-GPResultantSetOfPolicy from the GroupPolicy module which is installed with the GPMC.Hope this helps,AshleyGoateePFE