query on mail contacts/mail users

Question

Hi All,

I am working in an Exchange 2016 hybrid environment. I have mail contacts and mail users in Exchange 2016, as well as mail contacts, mail users, and external users in Exchange Online. I also have distribution lists (DLs) in both Exchange On-Premises and Exchange Online.

Is it possible to identify the distribution lists, both on-premises and online, in which these mail contacts, mail users, and external users are members?

Please guide me.

Answer 1

Hello, @Rising Flight,

Welcome to the Microsoft Q&A platform!

Based on your requirements, I can help guide you through identifying the distribution lists (DLs) in which your mail contacts, mail users, and external users are members in both Exchange On-Premises and Exchange Online environments.

1. Connect to Exchange On-Premises: Open the Exchange Management Shell on your Exchange 2016 server and run the following command to get the distribution groups and their members.

Get-DistributionGroup | ForEach-Object { Get-DistributionGroupMember $_.Identity | Select-Object @{Name="GroupName";Expression={$_.Identity}}, Name, RecipientType }

2. Connect to Exchange Online: Open the Windows PowerShell and connect to Exchange Online using the following commands.

$UserCredential = Get-Credential
Connect-ExchangeOnline -UserPrincipalName $UserCredential.UserName -ShowProgress $true

Once connected, run the following command to get the distribution groups and their members.

Get-DistributionGroup | ForEach-Object { Get-DistributionGroupMember $_.Identity | Select-Object @{Name="GroupName";Expression={$_.Identity}}, Name, RecipientType }

3. Identify Members: The output of these commands will list all distribution groups along with their members, including mail contacts, mail users, and external users. You can export this information to a CSV file for easier analysis.

Get-DistributionGroup | ForEach-Object { Get-DistributionGroupMember $_.Identity | Select-Object @{Name="GroupName";Expression={$_.Identity}}, Name, RecipientType } | Export-Csv -Path "DistributionGroupMembers.csv" -NoTypeInformation

By running these commands, you will be able to identify the distribution lists in both your on-premises and online environments and see which mail contacts, mail users, and external users are members of each list.

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Thank you for your support and understanding.

Best Wishes,

Alex Zhang

Answer 2

Yes, you can identify which distribution lists both on-premises and in Exchange Online contain your mail contacts, mail users, and external users as members. Since you have a hybrid setup, you need to check both environments separately.

1.       For On-Premises Exchange 2016:- Run the following command using PowerShell -

Get-DistributionGroup | ForEach-Object {Get-DistributionGroupMember $_ | Where-Object {$_.PrimarySMTPAddress -eq "user@example.com"}}

2.       For Exchange Online:- First, connect to Exchange Online PowerShell by running-

Connect-ExchangeOnline -UserPrincipalName [admin@yourdomain.com]   

Run the command to see all distribution lists -

Get-DistributionGroup | ForEach-Object {Get-DistributionGroupMember $_ | Where-Object {$_.PrimarySMTPAddress -eq "user@example.com"}}

Replace email address with your emails. Let me know if you have any query in above steps.

Answer 3

Lets say i have a csv file in the below format. will the below syntax fetch me mailuser/mailcontact/externaluser that are members of the DL.

DLAlias
dl1@contoso.com
dl2@contoso.om

Import-Csv c:\windows\temp\list.csv | ForEach-Object {
    Get-DistributionGroup -Identity $_.DLAlias | ForEach-Object {
        Get-DistributionGroupMember -Identity $_.DLAlias | Where-Object {
            ($_.RecipientType -eq "MailUser") -or 
            ($_.RecipientType -eq "MailContact") -or 
            ($_.RecipientTypeDetails -eq "GuestMailUser") -or 
            ($_.RecipientTypeDetails -eq "ExternalUser")
        }
    }
}

will the above syntax fetch me external users created from Azure AD. how do i export the output to csv file. please guide me. will the above syntax work for unified groups if i change it from get-distributiongroup to get-unifiedgroup.