Hello, I am in the process of transitioning to Exchsrvr 2010 from Exchsrvr 2003. In our setup we have two CAS/HT servers (MS NLB) and two MBX server (clustered). I completed installing and configuring CAS/HT servers. I created a CAS Array for OWA and is called owa.scs.com.Our internal DNS has a A record for owa and NLB is configured with cluster name "owa.scs.com" with two hosts (two CAS servers). All our mailboxes are still on Exchsrvr 2003. I like to load balance MAPI using NLB. Can I use the same array connector I configured for owa or should i create a new array connector for MAPI access? if so will NLB allow to have multiple clusters configured? Is it possible to have to have two array connectors in the same site , one for OWA and other for MAPI? Thanks in advance Tom

Hi Tom, Based on my experience, in Exchange Server 2003 , internal Outlook MAPI clients connected directly to the back-end servers via MAPI over RPC. If you are talking about Exchange Server 2010, and you want to use Exchange 2010 CAS Array to load balance MAPI, please refer to these documents: How to setup an Exchange 2010 CAS Array to load balance MAPI http://blogs.technet.com/b/ucedsg/archive/2009/12/06/how-to-setup-an-exchange-2010-cas-array-to-load-balance-mapi.aspx Uncovering the new RPC Client Access Service in Exchange 2010 (Part 1) http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/uncovering-new-rpc-client-access-service-exchange-2010-part1.html Thanks, EvanPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Also don't forget to see section "What Persistence (affinity) type should I use? " in below link http://www.msexchange.org/articles_tutorials/exchange-server-2010/high-availability-recovery/load-balancing-exchange-2010-client-access-servers-using-hardware-load-balancer-solution-part1.html Anil