Haikos Blog Posts

[string[]]$global:AllreadyChecked = $null
 
function Get-DistributionGroupAllParents
{
    param ([string]$GroupName)
 
    [string[]]$Parents = $null
 
    ForEach ($Group in Get-DistributionGroup) 
    {
       If((Get-DistributionGroupMember $Group.Name | Where RecipientType -NE "UserMailbox").Name -contains $Groupname)
       {
          # Make sure, we are only checking every DGs parents once as many DG tree leafs may lead to the same parent DG
          If($global:AllreadyChecked -notcontains ($Group.Name))
          {
                $Parents += $Group.Name
                Get-DistributionGroupAllParents -GroupName $Group.Name
                $global:AllreadyChecked += $Group.Name
          }
       } 
    }
    Return $Parents
}
 
# Connect to Office 365
If((Get-PSSession | Where Computername –like "*ps.outlook.com*" | Where State –eq "Opened" | Measure-Object).Count -lt 1)
{
    $Credentials = Get-Credential –UserName "USER@DOMAIN.COM" -Message "Please enter your Office 365 / Azure AD password!"
    $ExchangeSession = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell -Credential $Credentials -Authentication Basic -AllowRedirection -WarningAction SilentlyContinue
    Import-PSSession $ExchangeSession -AllowClobber -DisableNameChecking >> $null
}
elseif((Get-PSSession | Where Computername -like "*ps.outlook.com*" | Where Availability -eq "Available" | Where State -ne "Opened" | Measure-Object).Count -ge 1)
{
    Import-PSSession -Session (Get-PSSession | Where Computername -like "*ps.outlook.com*" | Where Availability -eq "Available" | Select -Last 1)
}
 
# Get all DGs a user is member of
$User = Read-Host -Prompt "Enter User to check!" 
$Recipient = (Get-Recipient -RecipientType UserMailbox -Identity $User).Name
Write-Host "Script started discovery - this could take a while" -ForegroundColor Red
 
[string[]]$AllParents = $null
ForEach ($Group in Get-DistributionGroup) 
{
   If((Get-DistributionGroupMember $Group.Name).Name -contains $Recipient)  # Find all Groups the User is immediate member of:
   {
      $AllParents += $Group.Name
      Write-Host -ForegroundColor Green "$($Group.Name) ($($Group.PrimarySmtpAddress))"
      $AllParents += (Get-DistributionGroupAllParents -Group $Group.Name)
   } 
}
 
Write-Host "User is member of these groups (for some of them, he may be member through nested groups!):"
$AllParents.Where({ $_ -ne "" }) | select -uniq | sort | Get-DistributionGroup | ft DisplayName,Name,PrimarySmtpAddress -AutoSize

[string[]]$global:AllreadyChecked = $null function Get-DistributionGroupAllParents { param ([string]$GroupName) [string[]]$Parents = $null ForEach ($Group in Get-DistributionGroup) { If((Get-DistributionGroupMember $Group.Name | Where RecipientType -NE "UserMailbox").Name -contains $Groupname) { # Make sure, we are only checking every DGs parents once as many DG tree leafs may lead to the same parent DG If($global:AllreadyChecked -notcontains ($Group.Name)) { $Parents += $Group.Name Get-DistributionGroupAllParents -GroupName $Group.Name $global:AllreadyChecked += $Group.Name } } } Return $Parents } # Connect to Office 365 If((Get-PSSession | Where Computername –like "*ps.outlook.com*" | Where State –eq "Opened" | Measure-Object).Count -lt 1) { $Credentials = Get-Credential –UserName "USER@DOMAIN.COM" -Message "Please enter your Office 365 / Azure AD password!" $ExchangeSession = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell -Credential $Credentials -Authentication Basic -AllowRedirection -WarningAction SilentlyContinue Import-PSSession $ExchangeSession -AllowClobber -DisableNameChecking >> $null } elseif((Get-PSSession | Where Computername -like "*ps.outlook.com*" | Where Availability -eq "Available" | Where State -ne "Opened" | Measure-Object).Count -ge 1) { Import-PSSession -Session (Get-PSSession | Where Computername -like "*ps.outlook.com*" | Where Availability -eq "Available" | Select -Last 1) } # Get all DGs a user is member of $User = Read-Host -Prompt "Enter User to check!" $Recipient = (Get-Recipient -RecipientType UserMailbox -Identity $User).Name Write-Host "Script started discovery - this could take a while" -ForegroundColor Red [string[]]$AllParents = $null ForEach ($Group in Get-DistributionGroup) { If((Get-DistributionGroupMember $Group.Name).Name -contains $Recipient) # Find all Groups the User is immediate member of: { $AllParents += $Group.Name Write-Host -ForegroundColor Green "$($Group.Name) ($($Group.PrimarySmtpAddress))" $AllParents += (Get-DistributionGroupAllParents -Group $Group.Name) } } Write-Host "User is member of these groups (for some of them, he may be member through nested groups!):" $AllParents.Where({ $_ -ne "" }) | select -uniq | sort | Get-DistributionGroup | ft DisplayName,Name,PrimarySmtpAddress -AutoSize