Reverse proxy is the system which handles the entire incoming HTTP(S) traffic. This incoming HTTP(S) traffic includes data such as address books, web services or distribution group expansion and other, supposed anonymous traffic such as access to dial-in conferences or meetings. User connections to these components are fronted with forms-based access pages. In total, there are three pages offering forms-based authentication; Dial-In, Meet and Scheduler.

Dial-In is the landing page for audio conferences. When a conference is planned and the link has been sent to possible participants, this page is accessed to find dial-in numbers. This webpage is accessible anonymously. However, there is a sign-in option that Lync users which are homed in this system can access to see their own dial-in parameters and preferences.

Meet is the landing page for the Lync Web App. If the page is accessed without a valid conferencing ID, Lync provides an error page. If a correct conference ID has been entered, it will either redirect the connection to a locally-installed Lync client or it will present the meeting login page. A forms-based login page for anonymous users provides only a naming identifier. The second option for Lync system-homed users allows the users to identify themselves with their Active Directory domain credentials.

Scheduler is the meeting planning landing page. If a user does not have the Outlook client installed, including a local Lync client installation, they need this (manually) configured web page to access and plan Lync meeting/conferences. It has a forms-based login page for domain-authenticated users.

Other web services consist of everything else that Lync, Mobil, App Store and Rich clients require. These services can only be accessed by users if they have authenticated themselves again in the Active Directory and if they have a valid session ticket assigned. Further details regarding the IIS components in Lync are discussed later in this document.

Note: Even though there is forms-based authentication, users cannot be pre-authenticated using Reverse Proxy. This is not a supported configuration. Lync-provided forms-based authentication simplifies the deployment – so a simple, but Lync-aware web traffic redirect can be used.