I want to use RPC over HTTP so the the remote users or clients can use Office Outlook from anywhere without logging to the domain. here is the scenario adnan@abc.com is the primary account on the AD on the default domain abc.com adnan@xyz.com is the hosted account on the same server but configured to have their own domain address list. How do I enable RPC/HHTP to make sure it works fine internall and as well as externally. in other words trying to provide Office Outlook to the hosted domains. thanks in advance.

Are they bout in the same Ecxhange Organization, if soo there is no problem, it should work. Just follow the article http://technet.microsoft.com/en-us/library/aa998934(EXCHG.80).aspx

Yes, You can use outlook anywhere for alias address too. only you should able to acess OWA URL from external and then configure it. Post here if you face any error.Anil