Exchange Services Publishing

Many components of Lync rely on connections to Exchange Web Services (EWS), a web-based component of Exchange Server since 2007. The Lync client itself is fairly resilient to falling back to MAPI calls to Outlook for information, but clients like Lync Phone Edition or Lync Mobile for Apple’s iOS platform are heavily dependent on Exchange Web Services being published remotely.

Exchange Web Services are typically published through the same reverse proxy Lync uses, but in some cases organizations might restrict access to Outlook or Exchange Web Services from remote clients. It’s important to discuss Exchange Web Services early on when planning to provide remote Lync services because it can greatly affect the user experience. For example, remote Lync Phone Edition users might be unable to view visual voice mail, access calendar data, or see all call history if EWS is not published. And Lync Mobile for iOS clients cannot view any calendar data or join Online Meetings if EWS is not accessible.

Organizations that rely on products like Good Technology instead of Microsoft ActiveSync for mobile email might also miss out on some features for the Windows Phone and Android mobile platforms in which Lync Mobile integrates with the native calendar and contact applications. The take-away here is that Lync endpoints leverage many components of Exchange, so it is important to ensure that Exchange services are also properly published through a reverse proxy when planning a Lync deployment.