Consider the following scenario:
- You are in a Microsoft Exchange Server 2013 and legacy Exchange Server (Exchange Server 2010 or Exchange Server 2007) co-existence environment.
- There is more than one legacy Exchange Client Access (CAS) server in the environment.
- Outlook Anywhere is enabled on both the legacy Exchange and Exchange 2013 CAS servers.
- Users who have their mailboxes on the legacy Exchange CAS servers connect to the Exchange 2013 CAS server by using Outlook Anywhere. The users are proxies to one of the legacy Exchange CAS servers from the Exchange 2013 CAS server.