PowerShell/Office 365 - Get the distribution groups membership

I was recently looking at Office365/Exchange Online to retrieve Distribution Group membership. This is pretty simple using something like: Get-DistributionGroupMember -Identity "Marketing"

Not that prior to perforce the following command you need to be already connected to Office365, see this post.

Retrieving all members of each Distribution Group

Now if I want to retrieve all the Distribution group members, it’s bit trickier you’ll see. First I started by listing the groups members. My PowerShell instinct made me type Get-DistributionGroup | Get-DistributionGroupMember but it did not work, see below:

As the error message is stating that this Cmdlet does not accept input :-/

By using Get-Help on Get-DistributionGroupMember, we can check the parameters accepting Input:

(Get-Help Get-DistributionGroupMember).parameters.parameter|
    Select-Object name,parametervalue,pipelineinput

The Identity parameter is not accepting the value by property name, so we have to specify Identity before we send the output to Get-DistributonGroupMember

(Get-DistributionGroup -ResultSize 5).identity|
    Get-DistributionGroupMember

The above output does the job but we do not know which group they belong to. You can include the Distribution group name in the output using the following:

(Get-DistributionGroup).identity | ForEach-Object{
    $DistributionGroupName = $_
    Get-DistributionGroupMember -Identity $_ | ForEach-Object{
        [PSCustomObject]@{
            DistributionGroup = $DistributionGroupName
            MemberName = $_.Name
            #Other recipient properties here
        }
    }
}

Retrieving a single Distribution Group membership

Pretty similar to the one above, just specify the name of the Distribution Group

(Get-DistributionGroup -Identity 'Sales').identity | ForEach-Object{
    $DistributionGroupName = $_
    Get-DistributionGroupMember -Identity $_ | ForEach-Object{
        [PSCustomObject]@{
            DistributionGroup = $DistributionGroupName
            MemberName = $_.Name
            #Other recipient properties here
        }
    }
}

Retrieving Distribution Groups membership with a specific name pattern

You can also specify the pattern of distribution groups you are looking for. Here it will return all the Distribution Group starting by MTL.

(Get-DistributionGroup -Identity 'MTL*').identity | ForEach-Object{
    $DistributionGroupName = $_
    Get-DistributionGroupMember -Identity $_ | ForEach-Object{
        [PSCustomObject]@{
            DistributionGroup = $DistributionGroupName
            MemberName = $_.Name
            #Other recipientproperties here
        }
    }
}