IM filter doesn't work if network path has host server name in Skype for Business Server 2015

Applies to: Skype for Business Server 2015

Symptoms


In Microsoft Skype for Business Server 2015, you configure an instant messaging (IM) filter to prevent an end-user from sending an IM message that contains a network path, for example, \\server. The IM filter doesn’t work as expected and the link is still clickable.

Resolution


To fix this issue, install the May 2020 cumulative update 6.0.9319.580 for Skype for Business Server 2015, Front End Server and Edge Server.
To enable this fix, you also need to set the -IgnoreLocal parameter to False by running the Set-CsImFilterConfiguration cmdlet and then restart the service.