LS, I have now 2 CAS/HUB server with Exchange 2007 and 2 MBX servers Exchange 2007. I want to install Exchange 2010 within the same organisation. The approach I want to do is: 1 install Exchange 2010 CAS 2. install Exchange 2010 HUB 3. install Exchange 2010 MBX I don't want to make use of legacy url etc. I move all the mailboxes, which uses EAS and OWA at the same time and then reconfigure TMG to point to new CAS (2010) server. I have only outlook 2010 clients. Is this going to work? (so does 2010 CAS have inpact on working of the CAS for Exchange 2007 ? ) Regards, Peter

There is a possibility that introducing a new CAS into the site will cause Autodiscover to reply to clients with its name. Therefore, change the InternalURL settings on virtual directories to your existing URL until you're ready for clients to use it.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hello, Configuring a legacy host name is necessary only if you'll need Exchange 2007 and Exchange 2010 to coexist in the same organization. If you have a small number of mailboxes and can move all your mailboxes from Exchange 2007 to Exchange 2010 during the downtime you've scheduled for the upgrade, this step isn't necessary. Thanks, Simon Wu Exchange Forum Support Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com