I have been searching for a few answer that i can not seem to find answers to. I'm hoping someone can help me out with my three questions. I have been looking at forum post and i seem to get a lot of conflicting info or maybe i'm not searching for the write terms but any help would be great. Setup: I currently have 4 existing Exchange 2007 servers. 2 CAS/HUB servers and 2 Mailbox servers in CCR. We are moving to Exchange 2010, so i have built 4 new servers. 2 CAS/HUB and 2 Mailbox servers using DAG. I have the exch2010 CAS/HUB servers setup using Network Load Balancer for OWA balancing. Question 1: I want to create the CAS array but do i need to create the CAS array with new IPs and DNS name or can it be setup to use the existing NLB setup with the same DNS name? Question 2: If i do create the CAS Array will it ignore my two existing 2007 CAS servers? Question 3: Do i need to have a DNS entry for addressing the DAG?

1. just cause i wasn't clear above, the NLB is only setup on the Exch2010 CAS/HUB. The exchange 2007 CAS/HUB have no NLB setup on them. Take it the answer is still the same? 2. so i can not create the CAS array until i have removed the Exch2007 CAS servers?

You can create a new array for the Exchange 2010 CAS/HT servers as part of the initial build before migrating users to the Exchange 2010 system, it will not affect the Exchange 2007 environment at all. And yes point 1 does not change :)Matt Cline - MCSE+M, MCITP: EA | EMA (2007, 2010) | Lync 2010 Blog: exchangeadventures.wordpress.com