Carl Webster | The Accidental Citrix Admin

Finding Domain Trusts in an Active Directory Forest using Microsoft PowerShell

April 21, 2014

Active Directory, PowerShell
For my Active Directory (AD) documentation script, I needed to enumerate all Trusts for a Domain. I found a script on TechNet but it had issues. I fixed the issues but I cannot post it as a solution on TechNet because my script is longer than 2000 characters.

I found the original script here.

My issues with the original script are:
- No error checking
- Did not handle singletons
- Did not use its $DomainDNS variable in the Get-ADObject call to specify which domain to restrict the trusts
- The $TrustAttributesNumber variable used decimal values instead of hexadecimal values (i.e. 20 instead of 32)
- The $TrustAttributesNumber variable did not have a value for Inter-Forest trusts (hex 64)
- The Switch statements did not use Default but used an If statement after the Switch statement to set the Default value
Here is my version of the script.
```
#http://gallery.technet.microsoft.com/scriptcenter/Enumerate-Domain-Trusts-25ecb802#content
Import-module ActiveDirectory
$Domains = (Get-ADForest).Domains

If($? -and $Domains -ne $Null)
{
	ForEach($Domain in $Domains)
	{ 
		Write-output "Get list of AD Domain Trusts in $Domain `r"; 
		$ADDomainTrusts = Get-ADObject -Filter {ObjectClass -eq "trustedDomain"} -Server $Domain -Properties * -EA 0

		If($? -and $ADDomainTrusts -ne $Null)
		{
			If($ADDomainTrusts -is [array])
			{
				[int]$ADDomainTrustsCount = $ADDomainTrusts.Count 
			}
			Else
			{
				[int]$ADDomainTrustsCount = 1
			}
			
			Write-Output "Discovered $ADDomainTrustsCount trusts in $Domain" 
			
			ForEach($Trust in $ADDomainTrusts) 
			{ 
				$TrustName = $Trust.Name 
				$TrustDescription = $Trust.Description 
				$TrustCreated = $Trust.Created 
				$TrustModified = $Trust.Modified 
				$TrustDirectionNumber = $Trust.TrustDirection
				$TrustTypeNumber = $Trust.TrustType
				$TrustAttributesNumber = $Trust.TrustAttributes

				#http://msdn.microsoft.com/en-us/library/cc220955.aspx
				#no values are defined at the above link
				Switch ($TrustTypeNumber) 
				{ 
					1 { $TrustType = "Downlevel (Windows NT domain external)"} 
					2 { $TrustType = "Uplevel (Active Directory domain - parent-child, root domain, shortcut, external, or forest)"} 
					3 { $TrustType = "MIT (non-Windows) Kerberos version 5 realm"} 
					4 { $TrustType = "DCE (Theoretical trust type - DCE refers to Open Group's Distributed Computing Environment specification)"} 
					Default { $TrustType = $TrustTypeNumber }
				} 

				#http://msdn.microsoft.com/en-us/library/cc223779.aspx
				Switch ($TrustAttributesNumber) 
				{ 
					1 { $TrustAttributes = "Non-Transitive"} 
					2 { $TrustAttributes = "Uplevel clients only (Windows 2000 or newer"} 
					4 { $TrustAttributes = "Quarantined Domain (External)"} 
					8 { $TrustAttributes = "Forest Trust"} 
					16 { $TrustAttributes = "Cross-Organizational Trust (Selective Authentication)"} 
					32 { $TrustAttributes = "Intra-Forest Trust (trust within the forest)"} 
					64 { $TrustAttributes = "Inter-Forest Trust (trust with another forest)"} 
					Default { $TrustAttributes = $TrustAttributesNumber }
				} 
				 
				#http://msdn.microsoft.com/en-us/library/cc223768.aspx
				Switch ($TrustDirectionNumber) 
				{ 
					0 { $TrustDirection = "Disabled (The trust relationship exists but has been disabled)"} 
					1 { $TrustDirection = "Inbound (TrustING domain)"} 
					2 { $TrustDirection = "Outbound (TrustED domain)"} 
					3 { $TrustDirection = "Bidirectional (two-way trust)"} 
					Default { $TrustDirection = $TrustDirectionNumber }
				}
					   
				Write-output "`tTrust Name: $TrustName `r " 
				Write-output "`tTrust Description: $TrustDescription `r " 
				Write-output "`tTrust Created: $TrustCreated `r " 
				Write-output "`tTrust Modified: $TrustModified  `r " 
				Write-output "`tTrust Direction: $TrustDirection `r " 
				Write-output "`tTrust Type: $TrustType `r " 
				Write-output "`tTrust Attributes: $TrustAttributes `r " 
				Write-output " `r " 
			}
		}
		ElseIf(!$?)
		{
			#error retrieving domain trusts
			Write-output "Error retrieving domain trusts for $Domain"
		}
		Else
		{
			#no domain trust data
			Write-output "No domain trust data for $Domain"
		}
	} 
}
ElseIf(!$?)
{
	#error retrieving domains
	Write-output "Error retrieving domains"
}
Else
{
	#no domain data
	Write-output "No domain data"
}
```
The original script only processed the domain in which the user was running the script. I changed it to process all domains in the forest.

I am using Write-Output as that is what the original script uses. I will update this code to work in my script using my normal output routines.

Thanks

Webster
get-adforest, get-adobject, powershell domain trusts, powershell forest trusts
About Carl Webster

Webster is a Sr. Solutions Architect for Choice Solutions, LLC and specializes in Citrix, Active Directory and Technical Documentation. Webster has been working with Citrix products for many years starting with Multi-User OS/2 in 1990.
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15 Responses to “Finding Domain Trusts in an Active Directory Forest using Microsoft PowerShell”
1. Bhaskar Raman Says:
  September 14, 2024 at 12:43 am
  A very naive question.
  
  1. Need permission to plagarize the script.
  2. How do I run the script?
  - Carl Webster Says:
    September 17, 2024 at 3:37 am
    1. Permission granted.
    2. Copy and paste the script into ISE or a PowerShell prompt.
    
    Thanks
    
    Webster
2. Glenn Says:
  June 16, 2023 at 5:31 pm
  I like this script, is there a way to write this to a file or html report?
  - Carl Webster Says:
    June 23, 2023 at 12:02 pm
    This is included in my AD documentation script starting at line 10620.
    
    Webster
3. zhiaga Says:
  December 1, 2015 at 11:43 am
  I got this error, help me please
  
  Get-ADObject : Error parsing query: ‘ObjectClass -eq “trustedDomain”;’ Error Message: ‘Operator Not supported: ‘ at
  position: ’32’.
  At C:\scripts\Get-ADTrusts-v2.ps1:42 char:27
  + $ADDomainTrusts = Get-ADObject -Filter {ObjectClass -eq “trustedDomain”; …
  + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  + CategoryInfo : ParserError: (:) [Get-ADObject], ADFilterParsingException
  + FullyQualifiedErrorId : Error parsing query: ‘ObjectClass -eq “trustedDomain”;’ Error Message: ‘Operator Not sup
  ported: ‘ at position: ’32’.,Microsoft.ActiveDirectory.Management.Commands.GetADObject
  - Carl Webster Says:
    December 1, 2015 at 12:03 pm
    This is usually a copy and paste issue. Make sure all the “-“s in your script are real “-“s. Copy what you see as a “-” and then do a replace with the “-” from your keyboard. That always fixes the issue for me.
    
    Thanks
    
    Webster
    
    Adriano Ciampoli Says:
    April 7, 2016 at 1:55 pm
    I get the same error
    
    Get-ADObject : Error parsing query: ‘ObjectClass -eq “trustedDomain”;’ Error Message: ‘Operator Not supported: ‘ at position: ’32’.
    At line:6 char:27
    + … ainTrusts = Get-ADObject -Filter {ObjectClass -eq “trustedDomain”;} – …
    + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo : ParserError: (:) [Get-ADObject], ADFilterParsingException
    + FullyQualifiedErrorId : ActiveDirectoryCmdlet:Microsoft.ActiveDirectory.Management.ADFilterParsingException,Microsoft.ActiveDirectory.Management.Commands.GetADObject
    
    Carl Webster Says:
    April 7, 2016 at 1:59 pm
    Standard copy & paste error. Replace what looks like a – with what is on the same key as the underscore character.
    
    Webster
    
    Adriano Ciampoli Says:
    April 7, 2016 at 2:20 pm
    Actually there is a ; in the line below
    $ADDomainTrusts = Get-ADObject -Filter {ObjectClass -eq “trustedDomain”;} -Server $Domain -Properties * -EA 0
    
    I removed it and it works.
    
    Carl Webster Says:
    April 7, 2016 at 2:40 pm
    Actually looking back at other comments, several people have noted that. I thought I had removed it from the article.
    
    Webster
4. manoj Says:
  August 19, 2015 at 9:37 am
  $ADDomainTrusts = Get-ADObject -Filter {ObjectClass -eq “trustedDomain”;} -Server $Domain -Properties * -EA 0
  
  should be
  
  $ADDomainTrusts = Get-ADObject -Filter ‘ObjectClass -eq “trustedDomain”‘ -Server $Domain -Properties * -EA 0
  - Carl Webster Says:
    August 19, 2015 at 10:19 am
    From my PowerShell mentor Michael B. Smith:
    
    The truth is, it doesn’t matter. The way you wrote it minimizes quoting requirements and it is the way all of the examples for the parameter are written. You do have an unneeded semicolon though. 
    
    This is just the way PowerShell works. All of the below produce equivalent results:
    
    { this is a test }
    “ this is a test “
    ‘ this is a test ‘
    
    Using a quoted string is slightly more efficient the first time it’s executed, but based on the way PowerShell caches the AST it doesn’t make any difference on subsequent executions.
    
    Note: AST = Abstract Syntax Trees
    
    Thanks
    
    Webster
5. Rejone Says:
  July 24, 2014 at 3:09 pm
  Hi Jeremy;
  
  Great info. We have an issue with a child domain. We recently deployed Citrix VDI and all of our virtual machines are not able to ping our child domain controllers. Have you seen this issue before? Any help would be appreciated.
  
  Rejone
  - Jeremy Saunders Says:
    July 31, 2014 at 9:01 pm
    Hi Rejone,
    
    Not sure if your question was for Webster or myself.
    
    I would expect this to be a host (Windows) firewall issue, but we would need more information from you before concluding that this is the issue:
    – Are the VMs also in the child domain?
    – Can the VMs communicate with the child domain controllers on other ports, such as LDAP, browse to the SYSVOL, etc?
    
    As this question is unrelated to Webster’s script it’s probably a question that would be better posed on a forum so that others can join in the discussion to assist you.
    
    Cheers,
    Jeremy
6. Jeremy Saunders Says:
  April 21, 2014 at 9:13 pm
  Nice work Webster. I found the same issue with that script, but haven’t had the time to re-write it.
  
  You may also want to report whether or not the trust supports AES encryption by examining the value of the msDS-SupportedEncryptionTypes attribute. If enabled the value is typically 24 (8 = AES 128 bit key length, 16 = AES 256 bit key length)
  
  If it’s a forest trust, you’ll want to to get the Name Suffix Routing from the msDS-TrustForestTrustInfo attribute, which you can only do by examining the output of the “netdom trust” command.
  – http://blogs.msdn.com/b/spatdsg/archive/2008/08/21/kerberos-domain-routing.aspx
  – http://xitnotes.wordpress.com/2012/03/29/kerberos-in-an-active-directory-forest-trust-vs-external-trust/
  
  Cheers,
  Jeremy