To block file transfers through the Lync Access Edge service without affecting other Edge services follow these simple steps.
- Apply the Lync CU4 updates to your Lync servers.
- From the Lync Management Shell run the following command:
New-CsImFilterConfiguration -Identity EdgePoolIdentity -BlockFileExtension $true -Action Block -Enabled $true
EdgePoolIdentity is a placeholder for the identity of the Edge Server pool that is retruned by running the Get-CsService –EdgeServer command. You can also use the Edge Server pool instead of the identity. (IE: EdgeServer:EdgePool.aspoc.net) Repeat the command for each Edge Pool in your environment.
Reference: http://support.microsoft.com/kb/26218402,626 views