Static RPC Ports on an Exchange 2010 Client Access Server and outlook anywhere

Hi,

We are planning to configure static ports for RPC and Address book service as x and y respectively.

Is it required that we open these ports on the firewall for Outlook anywhere clients?

I had referred the below link but i did not get a clear picture whether we require these ports for outlook anywhere clients or not?

http://social.technet.microsoft.com/wiki/contents/articles/864.configure-static-rpc-ports-on-an-exchange-2010-client-access-server-en-us.aspx?PageIndex=2