The Lync client integrates with Exchange Server to enable many features in the Lync Client. Having both Lync Server and Exchange server really enables Unified Communications. Based on the Exchange version you have different integration options. Here are some examples of those integrations that only work when Exchange Webservices are discoverable and configured in Exchange: Contact Information, Calendar Information, Conversation History, Missed Conversations, Missed Calls, Voice Mail Playback, Unified Contact Store, High Resolution Photo’s, …
While this is great there is a difference in how Lync connects to Exchange compared to Outlook.
When customers want to add Lync to their application stack we have to make sure that the Exchange Autodiscover process works as expected. Unfortunately Outlook and Lync do not use the same process to discover the Exchange Web Services when connecting from the Local Area Network (LAN). Most customers don’t implement the Exchange Autodiscover process correctly.
Outlook checks the Service Connection Point (SCP) in Active Directory first and uses this information to connect to the Exchange CAS Server, using this method there is a side effect that because it is an Authoritative Source for Exchange connectivity and the client will not prompt for any Certificates issues (by default Exchange uses a Self Signed certificate for the Web Services which you should change as soon as possible)
Now adding Lync at the Customer puts some other requirements for the Exchange Autodiscover process. The Lync client does not query the Service Connection Point (SCP) in Active Directory as outlined in the drawing below.
Autodiscover Process for Exchange Web Services by Lync (in specified order)
3. http://AutoDiscover.<smtpdomain> /Autodiscover/Autodiscover.xml
4. _autodiscover._tcp.<smtpdomain> (Autodiscover DNS SRV Record)
Because the Lync client only uses DNS to discover the Exchange Web Services and Outlook does not (internally) most customers have to change their Exchange configuration. While most Admins do not configure Exchange Web Services correctly because not required by Outlook they have to reconfigure the environment for Lync.
Have the Exchange Admins configure the Exchange Autodiscover process correctly, not only for Outlook but also for the Lync client
Reconfiguring Exchange involves a lot of steps; Changing Certificates, Changing DNS entries, Changing Exchange Configuration … This is not something the Exchange Admin wants to do often and must be planned thoroughly.
A workaround exists to configure both Outlook & Lync client to dismiss Certificate Warnings if DNS entries are added for Exchange Autodiscover and Certificates/Configuration cannot be changed on Exchange.
The workaround is configuring both clients by GPO with specific registry entries to disable the Certificate Popups.
While this is not an ideal solution it does work.
Microsoft should make the Exchange Autodiscovery process transparent for both Outlook & Lync.
Either make the DNS Entries mandatory or have Lync query the Service Connection Point in AD
More Information: Understanding and Troubleshooting Microsoft Exchange Server Integration
This document introduces you to some of the new client features that are available whenever Microsoft Lync Server 2010 communications software is integrated with Microsoft Exchange Server 2010.