Hello all, I am in the process of tarnsitioning from Exchange 2003 to Exchange 2010. I completed configuring CAS roles. I have configured a CASArray for MAPI/RPC access. All our mailboxes are still on Exchange 2003 and will be on Exchnage 2003 for a while. Should I set Exchange 2003 database to access this CASArray by running this command Set-MailboxDatabase DB1 -RpcClientAccessServer “outlook.test.local” or this setting is only applicable for Exchange 2010 databases? In our case we don't have Exchange 2010 MBX roles installed yet. Also once I install Exchange CAS roles will Exchange 2003 be functional without having HT roles configured? I like to split this implementations in seperate windows if possible with minimal downtime. In my case we forward all mails to a third party SMTP server located in the network. To brief it we don't plan to use Exchange 2010 Edge Transport role. Thanks in advanceTom

Since all your clients are already pointed to Exchange 2003, they shouldn't be affected by your installation. The confusion would result only if you pointed clients, i.e., recoconfigured Outlook, to point to the CAS array. If you were to point Outlook to the CAS array, it should redirect Outlook and cause the profile to be updated with the Exchange 2003 server name. The CAS array will, however, proxy ActiveSync traffic. If in your command example DB1 is an Exchange 2003 mailbox database, you can't do that, it is applicable only to Exchange 2010 mailbox databases. In a nutshell, your CAS array isn't of much value to Exchange 2003 users.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."