Gets all External Users Assigned to a SPO/OD4B site in O365

Get-ExternalUser.ps1

#requires -modules "PnP.PowerShell"
 
[System.Net.WebRequest]::DefaultWebProxy.Credentials = [System.Net.CredentialCache]::DefaultCredentials
[System.Net.ServicePointManager]::SecurityProtocol   = [System.Net.SecurityProtocolType]::Tls12  

# connect to the tenant

    Connect-PnPOnline `
        -Url         [https://$env:O365_TENANT-admin.sharepoint.com]https://$env:O365_TENANT-admin.sharepoint.com `
        -ClientId    $env:O365_CLIENTID `
        -Thumbprint  $env:O365_THUMBPRINT `
        -Tenant      $env:O365_TENANTID `
        -ErrorAction Stop

# get all ODSP Urls in the tenant

    $sites = Get-PnPTenantSite -IncludeOneDriveSites -Filter "LockState -ne 'NoAccess'"
   
# query each site for external users

    $pageSize = 50

    $guests = foreach( $site in $sites )
    {
        Write-Host "[$(Get-Date)] - Scanning site: $($site.Url)"

        do
        {
            $externalUsers = Get-PnPExternalUser -SiteUrl $site.Url -Position $position -PageSize $pageSize

            $externalUsers | Select-Object @{Name="SiteUrl"; E={$site.Url}}, AcceptedAs, DisplayName, UserPrincipalName, InvitedAs, InvitedBy, UniqueId, UserId, WhenCreated, IsCrossTenant

            $position += $pageSize
        }
        while( $externalUsers.Count -eq $pageSize )

        $position = 0
    }

    $timestamp = Get-Date -Format FileDateTime

    $guests | Export-Csv -Path "C:\_temp\SPO ExternalUsers_$timestamp.csv" -NoTypeInformation

metrics.ps1

<#
# collect some basic metrics on the results


$tenantSitesWithGuests = $externalUsers | Group-Object -Property "SiteUrl"
$spoSitesWithGuests    = $tenantSitesWithGuests | Where-Object -Property "Name" -notmatch "-my.sharepoint.com"
$od4bSitesWithGuests   = $tenantSitesWithGuests | Where-Object -Property "Name" -match    "-my.sharepoint.com"
$od4bsites             = $sites | Where-Object -Property "Template" -match    "SPSPERS"
$sposites              = $sites | Where-Object -Property "Template" -notmatch "SPSPERS"
$guestDomainGroups     = $externalUsers | Select-Object @{ Name="Domain"; Expression={ $_.AcceptedAs -split "@" | Select-Object -Index 1 }} | Group-Object Domain
$od4bSiteCount         = $od4bsites.Count
$spoSiteCount          = $sposites.Count

# break out spo site guest accounts by domain type
$spodomaintypes = foreach( $group in $spoSitesWithGuests )
{
    $x = [PSCustomObject] @{
            SiteUrl              = $group.Name
            CorporateDomainCount = 0
            PersonalDomainCount  = 0
         }

    foreach( $user in $group.Group )
    {
        if( $user.AcceptedAs -match "gmail.com|yahoo.com|outlook.com|live.com|hotmail.com|aol.com" )
        {
            $x.PersonalDomainCount++        
        }
        else
        {
            $x.CorporateDomainCount++        
        
        }
    }

    $x
}

# break out od4b site guest accounts by domain type
$od4bdomaintypes = foreach( $group in $od4bSitesWithGuests )
{
    $x = [PSCustomObject] @{
            SiteUrl              = $group.Name
            CorporateDomainCount = 0
            PersonalDomainCount  = 0
         }

    foreach( $user in $group.Group )
    {
        if( $user.AcceptedAs -match "gmail.com|yahoo.com|outlook.com|live.com|hotmail.com|aol.com" )
        {
            $x.PersonalDomainCount++        
        }
        else
        {
            $x.CorporateDomainCount++        
        
        }
    }

    $x
}

$table1 = $externalUsers | 
            Group-Object -Property SiteUrl |
                Select-Object Name, Count, @{ Name="Percent"; Expression={ ([Math]::Round( $_.Count / $sites.Count, 4)) * 100 }} | 
                    Sort-Object Name |
                        Format-Table -AutoSize |
                            Out-String

$table2 = [PSCustomObject] @{ 
                TotalSitesWithGuests = $tenantSitesWithGuests.Count
                TotalSites           = $urls.Count
                Percent              = [Math]::Round( ($tenantSitesWithGuests.Count/$urls.Count), 4) * 100
          } | Format-Table -AutoSize | Out-String

$table3 = $guestDomainGroups | 
                Select-Object Name, Count, @{ Name="Percent"; Expression={ ([Math]::Round( $_.Count / ($guestDomainGroups | Measure-Object -Property Count -Sum).Sum, 2)) * 100 }} | 
                    Sort-Object Percent -Descending |
                        Format-Table -AutoSize |
                            Out-String

$table4 = [PSCustomObject] @{ 
                SiteType                    = "SharePoint"
                SitesWithGuestsCount        = $spoSitesWithGuests.Count
                SitesWithCorpGuestsCount    = @($spodomaintypes | Where-Object -Property "CorporateDomainCount" -gt 0).Count
                SitesWithNonCorpGuestsCount = @($spodomaintypes | Where-Object -Property "PersonalDomainCount"  -gt 0).Count
                TotalSites                  = $spoSiteCount
                PercentWithGuests           = [Math]::Round( ($spoSitesWithGuests.Count / $sposites.Count), 4) * 100
                PercentWithCorpGuests       = [Math]::Round( ((($spodomaintypes | Where-Object -Property "CorporateDomainCount" -gt 0).Count) / $sposites.Count), 4) * 100
                PercentWithNonCorpGuests    = [Math]::Round( ((($spodomaintypes | Where-Object -Property "PersonalDomainCount"  -gt 0).Count) / $sposites.Count), 4) * 100
          },
          [PSCustomObject] @{ 
                SiteType                    = "OneDrive"
                SitesWithGuestsCount        = $od4bSitesWithGuests.Count
                SitesWithCorpGuestsCount    = @($od4bdomaintypes | Where-Object -Property "CorporateDomainCount" -gt 0).Count
                SitesWithNonCorpGuestsCount = @($od4bdomaintypes | Where-Object -Property "PersonalDomainCount"  -gt 0).Count
                TotalSites                  = $od4bSiteCount
                PercentWithGuests           = [Math]::Round( ($od4bSitesWithGuests.Count / $sposites.Count), 4) * 100
                PercentWithCorpGuests       = [Math]::Round( ((($od4bdomaintypes | Where-Object -Property "CorporateDomainCount" -gt 0).Count) / $sposites.Count), 4) * 100
                PercentWithNonCorpGuests    = [Math]::Round( ((($od4bdomaintypes | Where-Object -Property "PersonalDomainCount"  -gt 0).Count) / $sposites.Count), 4) * 100
          } | Sort-Object SiteType -Descending | Format-Table -AutoSize | Out-String

$table5 = [PSCustomObject] @{ 
                DomainType   = "Corporate"
                TotalDomains = $sposites.Count
                Percent      = [Math]::Round( ($spoSitesWithGuests.Count / $sposites.Count), 4) * 100
          },
          [PSCustomObject] @{ 
                DomainType   = "Personal"
                TotalDomains = ($domaintypes | Measure-Object -Property "PersonalDomainCount" -Sum).Sum
                Percent      = [Math]::Round( ($spoSitesWithGuests.Count / $sposites.Count), 4) * 100
          } | Sort-Object SiteType -Descending | Format-Table -AutoSize | Out-String

$table1
$table2
$table3
$table4
$table5

<# example output

Name                                                         Count Percent
----                                                         ----- -------
https://contoso.sharepoint.com/sites/ExternalSharing              3    0.35
https://contoso.sharepoint.com/sites/ModernSiteExtSharingTest     1    0.12
https://contoso.sharepoint.com/sites/target                       1    0.12
https://contoso.sharepoint.com/sites/teamsite                     7    0.81
https://contoso-my.sharepoint.com/                                1    0.12




TotalSitesWithGuests TotalSites Percent
-------------------- ---------- -------
                   5        867    0.58



Name                        Count Percent
----                        ----- -------
gmail.com                       3      23
outlook.com                     2      15
M365x797212.onmicrosoft.com     2      15
M365x050801.OnMicrosoft.com     2      15
M365B460882.onmicrosoft.com     1       8
blah.org                        1       8
contoso.com                     1       8
tailspin.com                    1       8


SiteType   SitesWithGuestsCount SitesWithCorpGuestsCount SitesWithNonCorpGuestsCount TotalSites PercentWithGuests PercentWithCorpGuests PercentWithNonCorpGuests
--------   -------------------- ------------------------ --------------------------- ---------- ----------------- --------------------- ------------------------
SharePoint                    4                        4                           2        847              0.47                  0.47                     0.24
OneDrive                      1                        0                           1         20              0.12                     0                        0


DomainType TotalDomains Percent
---------- ------------ -------
Corporate           847    0.47
Personal              5    0.47

#>

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