How to configure static ports for the RPC Client Access service, Exchange Address Book service, and public folder connections in Exchange 2010.

Often there are firewall restrictions in place between the Outlook client network and the Exchange 2010 messaging infrastructure network, which requires that static RPC ports are set on each Client Access Server in a Client Access array. In addition using static RPC ports usually reduces the memory footprint on the load balancer devices.

By default Windows Server 2008 and 2008 R2 are configured with a dynamic RPC range of 49152-65535 for outbound connections. Earlier versions of Windows Server by default used port 1025-65535 (for more details about this change see Microsoft KB article: The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008). Also, when the Exchange 2010 Client Access server role is installed on Windows Server 2008 or 2008 R2, the dynamic RPC port range is changed to 6005-59530 and the highest usable port number is set to 60554.

Links:

http://social.technet.microsoft.com/wiki/contents/articles/configuring-static-rpc-ports-on-an-exchange-2010-client-access-server.aspx
http://www.proexchange.be/blogs/exchange2010/archive/2010/04/08/configuring-static-ports-for-exchange-2010.aspx