Topic Last Modified: 2011-05-15

Microsoft Lync Server 2010 uses Microsoft Exchange Server 2010, Exchange Server 2010 with Service Pack 1 (SP1), and Microsoft Exchange Server 2007 with Service Pack 2 (SP2) Unified Messaging (UM) to provide voice mail, missed call notification, and auto-attendant services. An Exchange UM dial plan supports three different security levels: Unsecured, SIPSecured, and Secured. You configure security levels by means of the UM dial plan’s VoipSecurity parameter. The following table shows appropriate dial plan security levels depending on whether MTLS, SRTP, or both are enabled or disabled.

Table 1. VoIPSecurity Values for Various Combinations of Mutual TLS and SRTP

Security Level Mutual TLS SRTP

Unsecured

Disabled

Disabled

SIPSecured

Enabled (required)

Disabled

Secured

Enabled (required)

Enabled (required)

When integrating Exchange UM with Lync Server 2010, you need to select the most appropriate dial plan security level for each voice profile. In making this selection, you should consider the following: