Announcing Support for Controlled Connections to Public Folders in Outlook
Published Oct 19 2018 09:47 AM 19.5K Views

Up to now, Administrators did not have control over which users would see public folders in their Outlook clients. If public folders were created within the organization or if an Exchange Online organization is configured to access on-premises public folders, all clients would make a connection to and show the “Public folders” object in Outlook. From there, one could control access to individual public folders (controlled through folder permissions). However, it was difficult to have only some of Outlook clients connect to public folders. We are now introducing the ability to show the public folder object in Outlook to only a set of users who might need them. To get started, this will be available for Outlook for Windows users only. To do this, administrators can use two parameters:

  • PublicFolderClientAccess is an optional parameter on the user object. By default, its value is set to ‘false’. Setting this to ‘true’ on a specific user designates this user as one of users who will see public folders in Outlook.
  • PublicFolderShowClientControl parameter on the organization config. By default, the value of this parameter is also ‘false’ and once it is set to ‘true’, the controlled access of public folders is enabled.

Here is an example of how to use these parameters; to enable access to only the user “Administrator” and turn the feature on for the organization:

Set-CASMailbox “Administrator" -PublicFolderClientAccess $true
Set-OrganizationConfig -PublicFolderShowClientControl $true

Important note: setting the organization parameter to true without setting user attributes to true first will make it so no users will see the public folder object in Outlook for Windows. In other words – if you want to implement this, we suggest that you plan ahead and populate user attributes first (PublicFolderClientAccess on users that need access set to true) and then set the organization level parameter (PublicFolderShowClientControl set to true). That way, users who need to have access will not lose access unexpectedly.

Why would you want to do this?

Tenant admins will now have more flexibility over which users connect to public folders in Outlook. This will benefit very large organizations who might have issues with connection limits to public folders and will reduce the load to that infrastructure. This will also be helpful to organizations during mergers and acquisitions if moving to EXO. Imagine one organization having existing public folders, but after the companies merge – without this feature all of the users would unnecessarily connect to the public folder hierarchy.

Note: This feature is not intended to be replacement for public folder permissions, it is merely providing means to have more control over which clients connect to the public folder tree.

A few more questions answered that you might be interested in:

Will this work for only Outlook on Windows?

At this time, yes. We are working to bring this to additional clients (like Outlook for Mac or Outlook on the web) in the future and will talk about this later.

What about on-premises servers?

This feature shipped for on-premises servers in Exchange 2019 CU2 and Exchange 2016 CU13.

Is there a specific version of Outlook that I need to see changed behavior?

No. The feature works by removing the public folder information from the Autodiscover response to Outlook for Windows clients. Therefore, if the user is not enabled for public folder access they will simply not connect to the public folder tree no matter the version of Outlook for Windows they use.

In case of any questions, please do reach out to us via the comments section below. We are updating official documentation to add those parameters.

Public folder team

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