Integrating Lync 2013 with Exchange 2013 OWA using UM Certificate

In this article we'll go through integrating Lync 2013 with Exchange 2013 OWA utilising the existing Unified Messaging certificate.

Scenario
Exchange 2013 multi-role server has a public signed wildcard certificate *.domain.com being used for client access. Internally CA signed certificate is installed for Unified Messaging with the Exchange server fqdn in the subject and SAN (trusted by the Lync server).

Goal
Exchange 2013 client access server integrated with Lync 2013.

NOTE - If you don't have a unified messaging certificate installed with the server FQDN in subject & SAN, you will need to create a new certificate request, then get it signed by your internal CA to be used for the Lync/OWA integration.

Exchange Steps

1. Enable the OWA virtual directory for instant messaging
Run this in Exchange Management Shell:
Get-OwaVirtualDirectory | Set-OwaVirtualDirectory -InstantMessagingEnabled $true -InstantMessagingType OCS