Several steps must be performed to fully configure the Unified Messaging integration between Lync 2013 and Exchange 2013. We will start by describing the prerequisites to achieve this integration.
The following prerequisites must be in place in order to configure the Unified Messaging integration:
Microsoft Exchange Unified Messaging role: The UM role should be installed on an Exchange 2007 SP1 or later, Exchange 2010 RTM or later, or Exchange 2013 RTM or later versions.
Certificates: The Exchange UM certificate installed must be valid, signed by a certification authority who is trusted by the Lync Front End server(s). The Exchange server also needs to trust the certification authority who signed the Lync certificates. The Exchange certificate must have the FQDN of the Exchange Unified Messaging Server as a subject name and must ideally be issued by a private certification authority. Getting Exchange Unified Messaging from a public...