After AD FS is configured, external users who attempt to join Skype for Business meetings are presented with an AD FS multi-factor authentication webpage that contains the user name and password challenge along with any additional authentication methods that you have configured. You can enable multi-factor authentication by deploying Active Directory Federation Service (AD FS) federation server and enabling passive authentication in Skype for Business Server. In addition to user name and password, you can require additional authentication methods, such as smart cards or PINs, to authenticate users who are joining from external networks when they sign in to Skype for Business meetings. Skype for Business Web App, Skype Meetings App, and Skype for Business for Mac support multi-factor authentication. Enable Multi-Factor Authentication for Skype for Business Web App For details, see Setting Up Reverse Proxy Servers and DNS requirements for simple URLs in Skype for Business Server. In Skype for Business Server Edge Server deployments, an HTTPS reverse proxy in the perimeter network is required for Skype for Business Web App client access. You can either install the ActiveX control in advance or allow users to install it when prompted, which happens the first time they use Skype for Business Web App or the first time they access a feature that requires the ActiveX control.

The voice, video, and sharing features in Skype for Business Web App require a Microsoft ActiveX control that is used as a plugin by the user's browser. Whenever a user clicks a meeting URL but does not have the Skype for Business client installed, the user is presented with the option to join the meeting by using the latest version of Skype for Business Web App, Skype Meetings App, or Skype for Business for Mac. These meeting users are more often than not connecting from outside your network. Skype for Business Web App is an Internet Information Services (IIS) web client that is installed on the server running Skype for Business Server and by default it is deployed on demand to meeting users who do not already have the Skype for Business client.

Summary: Deploy the Skype for Business 2015 Web App and Skype Meetings App used with Skype for Business Server.

Microsoft skype web app