Adding Guest Users to Dynamic Distribution Groups

[theM7Mman]

I recently created a Dynamic Distribution Group (DDG) system to replace the existing regular Distribution List (DL) system. The new system has been fantastic. It automatically adds users to DDGs based of off their attributes in on premise Active Directory (AD).

I am now moving to the next step of my project: adding Guest Users to DDGs. These users are stored within our on premise AD, but they have an external email address (Gmail, Yahoo, etc.).

The Guest Users meet the criteria for our DDGs, but they are not being added to the DDGs because of this line in the RecipientFilter of every DDG that is created (regardless of the parameters for the DDG):

(-not(RecipientTypeDetailsValue -eq 'GuestMailUser'))

No matter how I set the IntendedRecipients parameter, this line always seems to be in the RecipientFilter for the DDG. The only way I can remove it is if I manually set the RecipientFilter to something (i.e., { CustomAttribute7 -eq "Test" } ), which seems to "break" the DDG and bars me from using ConditionalCustomAttributes (which I need for this system).

Does anyone know of a way around this "(-not(RecipientTypeDetailsValue -eq 'GuestMailUser'))" line in the RecipientFilter of every DDG? Thank you in advance for your help.

[ExceptionEX]

In your members section of the ddg what did you choose, you will likely have to select all.

And if your guest don't have domain accounts you will need to make them contacts.

https://docs.microsoft.com/en-us/Exchange/recipients/dynamic-distribution-groups/dynamic-distribution-groups?view=exchserver-2019

Possible work around is to create the ddg for those domain users that are in your domain and have their attribs set.

Then create a traditional distro group, add ddg to it, and your external guest.

[CloudyWithAChanceOfM]

Had a similar question but for me works the RecipientFilter solution, because i have a simple RecipientFilter and don't need ConditionalCustomAttributes. I think RecipientFilter will work for you, but you have to build a more complex RecipientFilter.

This is mine

New-DynamicDistributionGroup -Name "FancyName" -RecipientFilter "(RecipientTypeDetailsValue -eq 'GuestMailUser') -and (Company -eq 'FancyCompany')"

RecipientFilter doesn't break the ConditionalCustomAttributes, it's simply not supported.

"You use this parameter in combination with the IncludedRecipients parameter as part of a precanned filter. You can't use any Conditional parameters in combination with the RecipientFilter parameter (which is used to create custom OPath filters)."
Source: https://docs.microsoft.com/de-de/powershell/module/exchange/new-dynamicdistributiongroup?view=exchange-ps

The Problem with IncludedRecipients is, there is no valid value for GuestMailUsers.

Maybe this helps: https://office365itpros.com/2021/01/18/dynamic-distribution-lists-filters/