Microsoft® Exchange Server 2010 Inside Out

Outlook Anywhere

Outlook Anywhere is the component of Exchange 2010 that allows Outlook clients to connect to Exchange from the Internet using HTTPS. Basically, Outlook wraps the RPCs that it usually uses to connect to Exchange in an outer layer of HTTPS that can pass through firewalls. The CAS server strips the HTTPS and redirects the RPCs to the correct mailbox server. This solution avoids the need for clients to use VPNs to communicate with Exchange and the need for administrators to open up additional ports in corporate firewalls.

Outlook Anywhere is not enabled by default. You have to enable it on a CAS server in an Internet-facing Active Directory site to act as the initial entry point for client connections. You also need to enable Outlook ...