Hi, I am planning to install Exchange 2k7 on my network and allow it to coexist with the existing exchange 2k3. This is my design: Two MB server using single copy cluster (SCC) for high-availability Two CAS+HT server using network load balance option. Q1. If possible how do I go about installing the CAS & HT roles together and ensuring that the NLB works for both roles Q2. Would activesync work while this roles are coexisting? Thanks, IsaacIsaac2k2

Yes, you can. Just make sure that you haveexcludedHub Transport communication port 25 and 465 from load balancing because hubtransportsever has its ownmechanism. NLB and the CAS\HUB role http://blogs.msdn.com/douggowans/archive/2008/12/08/nlb-and-the-cas-hub-role.aspx Network Load Balance for HUB & CAS - Exchange 2007 http://exchangeserverinfo.com/2008/03/20/network-load-balance-for-hub--cas--exchange-2007.aspx Load Balancing Exchange 2007 Client Access Servers using Windows Network Load-Balancing Technology Part 1: Overview of Windows NLB Clusters http://www.msexchange.org/articles_tutorials/exchange-server-2007/high-availability-recovery/load-balancing-exchange-2007-client-access-servers-windows-network-technology-part1.html Load Balancing Exchange 2007 SP1 Hub Transport Servers using Windows Network Load Balancing Technology (Part 1) http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/load-balancing-exchange-2007-sp1-hub-transport-servers-windows-network-load-balancing-technology-part1.html Amit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com