Hi,I have a single Exchange 2003 server and would like to migrate/transition to Exchange 2007 CCR. I'm currently in the process of migrating to Windows 2008 domain + extending the schema for Exchange 2007.Q1. What is the best approach to this migration/transition?Q2. Implementing an Exchange 2007 CCR requires 2x servers + 1x Hub Transport & Client Access Server. Is this correct? So, I would actually require 3 servers for an Exchange 2007 CCR?Thanks in advance,Andrew

Hello Andrew, I assume that it is transition in same domain. Best approach is transition in coexistence environment, install CA, HT & then CCR servers in Exchange 2003 environment and move some test users to 2007 Server and check that it works perfectly. Exchange 2007 CCR requires 2x servers + 1x Hub Transport & Client Access Server = 3 servers works but if you put 2 NLB server for CA then would be great for high availability, HT doesnt required NLB and those are load balanced automatically but it is recommended to put on CA NLB servers so 2x CCR servers + 2x HT/CA NLB = 4 servers would be perfect with High Availability so whenever any single server down users are not affected. Here are some of the references for your deployment. Planning for Cluster Continuous Replication Installing Cluster Continuous Replication on Windows Server 2008 Scheduled and Unscheduled Outages Here are some of the tips for installation. A few tips for Exchange Server 2007 SCC & CCR clustered installations NLB Client Accessguide. Load Balancing Exchange 2007 Client Access Servers using Windows Network Load-Balancing Technology Part 1: Overview of Windows NLB Clusters Load Balancing Exchange 2007 Client Access Servers using Windows Network Load-Balancing Technology Part 2: Configuring the Windows NLB Cluster Load Balancing Exchange 2007 Client Access Servers using Windows Network Load-Balancing Technology Part 3: Creating Certificates and Testing Client Services Hope this helps you...