Static RPC Ports for Exchange 2010

By default Exchange 2010 uses a dynamic range of ports for RPC communication between Outlook clients and CAS servers. In most cases, dynamic ports are fine. However, you may want to configure static ports if there are firewalls between the clients and the CAS servers or to optimize load balancing. I was recently part of a project where we set static ports to optimize and simplify load balancing.

You can configure static ports for RPC client access, the address book service, and public folders.

A few notes to be aware of:

• The registry key for the address book is a string (REG_SZ) not a number (REG_DWORD).
• The registry key for public folders needs to be configured on the Mailbox server with the public folder database because clients communicate directly with the information store to get public folder data.
• The ports for RPC client access and the address book service are configured on CAS servers. All CAS servers should be configured with the same port to support load balancing.
• The method for changing the address book static port changes from Exchange 2010 RTM and SP1. The value from RTM is not retained when SP1 is installed.
• You can verify the static ports have taken effect by using netstat or Resource Monitor. Both of these utilities allow you to view listening ports and the executable that is listening.

This article has the details about which registry keys need to configured:  http://social.technet.microsoft.com/wiki/contents/articles/configure-static-rpc-ports-on-an-exchange-2010-client-access-server.aspx