We’re rolling out Lync Server 2010, and among other limits on end-user behavior, management wanted a way to prevent most, but not all, users from transfering files from their Lync or Microsoft Office Communicator clients.

Most client-related settings are controlled with Set-CsClientPolicy -Identity "MyAwesomeClientPolicy" -TheSettingName thesettingvalue, then granted to specific users with Grant-CsClientPolicy -PolicyName "MyAwesomeClientPolicy" -Identity SomeHaplessUser

Oddly enough, the right to transfer files or use audio/video in their peer-to-peer chats is not controlled with ClientPolicy, but by ConferencingPolicy. Our Global (that is, default) ConferencingPolicy have, among many other attributes, AllowIPAudio and AllowIPVideo set to False and EnableAppDesktopSharing set to None in order to keep most of the users on the less-expensive Standard Lync Server CALs during our testing period.

To test if “Keith’s” answer to this question in the MS TechNet forums about blocking file transfers for specific users or groups was correct, my colleague first sent a file from a test user with no explicitly-assigned ConferencingPolicy to her Lync user (which does have a more permissive ConferencingPolicy). Success.

I then ran:

Set-CsConferencingPolicy -Identity Global -EnableP2PFileTransfer $false

She signed the test user off and back on, and the test user’s Office Communicator did not display the option to transfer a file to her real account.

She then tried sending that test user a file. Denied!

My colleague was still able to send me a file, and vice versa, because we have the same (generous) conferencing policy, which since it was assigned to us, overrides the settings in the Global policy.

So, if the user has a ConferencingPolicy that has EnableP2PFileTransfer set to False, the user can neither send nor receive files in chat. However, they can still send and receive files in a conference. Set EnableFileTransfer to False to prevent the user from sending or receiving files in a conference he organizes. From cmdlet help for Set-CsConferencePolicy, it appears that he would still be able to send and receive files in a conference someone with EnableFileTransfer=True organized, but we have not tested that yet.

Other things set in CsConferencingPolicy affecting peer-to-peer chats that I thought would be in ClientPolicy:


AudioBitRateKB
EnableP2PRecording
EnableP2PVideo
VideoBitRate